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binfmt_flat: Fix integer overflow bug on 32 bit systems
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1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_SCHED_H
3 #define _LINUX_SCHED_H
4
5 /*
6  * Define 'struct task_struct' and provide the main scheduler
7  * APIs (schedule(), wakeup variants, etc.)
8  */
9
10 #include <uapi/linux/sched.h>
11
12 #include <asm/current.h>
13 #include <asm/processor.h>
14 #include <linux/thread_info.h>
15 #include <linux/preempt.h>
16 #include <linux/cpumask_types.h>
17
18 #include <linux/cache.h>
19 #include <linux/irqflags_types.h>
20 #include <linux/smp_types.h>
21 #include <linux/pid_types.h>
22 #include <linux/sem_types.h>
23 #include <linux/shm.h>
24 #include <linux/kmsan_types.h>
25 #include <linux/mutex_types.h>
26 #include <linux/plist_types.h>
27 #include <linux/hrtimer_types.h>
28 #include <linux/timer_types.h>
29 #include <linux/seccomp_types.h>
30 #include <linux/nodemask_types.h>
31 #include <linux/refcount_types.h>
32 #include <linux/resource.h>
33 #include <linux/latencytop.h>
34 #include <linux/sched/prio.h>
35 #include <linux/sched/types.h>
36 #include <linux/signal_types.h>
37 #include <linux/syscall_user_dispatch_types.h>
38 #include <linux/mm_types_task.h>
39 #include <linux/netdevice_xmit.h>
40 #include <linux/task_io_accounting.h>
41 #include <linux/posix-timers_types.h>
42 #include <linux/restart_block.h>
43 #include <uapi/linux/rseq.h>
44 #include <linux/seqlock_types.h>
45 #include <linux/kcsan.h>
46 #include <linux/rv.h>
47 #include <linux/livepatch_sched.h>
48 #include <linux/uidgid_types.h>
49 #include <asm/kmap_size.h>
50
51 /* task_struct member predeclarations (sorted alphabetically): */
52 struct audit_context;
53 struct bio_list;
54 struct blk_plug;
55 struct bpf_local_storage;
56 struct bpf_run_ctx;
57 struct bpf_net_context;
58 struct capture_control;
59 struct cfs_rq;
60 struct fs_struct;
61 struct futex_pi_state;
62 struct io_context;
63 struct io_uring_task;
64 struct mempolicy;
65 struct nameidata;
66 struct nsproxy;
67 struct perf_event_context;
68 struct pid_namespace;
69 struct pipe_inode_info;
70 struct rcu_node;
71 struct reclaim_state;
72 struct robust_list_head;
73 struct root_domain;
74 struct rq;
75 struct sched_attr;
76 struct sched_dl_entity;
77 struct seq_file;
78 struct sighand_struct;
79 struct signal_struct;
80 struct task_delay_info;
81 struct task_group;
82 struct task_struct;
83 struct user_event_mm;
84
85 #include <linux/sched/ext.h>
86
87 /*
88  * Task state bitmask. NOTE! These bits are also
89  * encoded in fs/proc/array.c: get_task_state().
90  *
91  * We have two separate sets of flags: task->__state
92  * is about runnability, while task->exit_state are
93  * about the task exiting. Confusing, but this way
94  * modifying one set can't modify the other one by
95  * mistake.
96  */
97
98 /* Used in tsk->__state: */
99 #define TASK_RUNNING                    0x00000000
100 #define TASK_INTERRUPTIBLE              0x00000001
101 #define TASK_UNINTERRUPTIBLE            0x00000002
102 #define __TASK_STOPPED                  0x00000004
103 #define __TASK_TRACED                   0x00000008
104 /* Used in tsk->exit_state: */
105 #define EXIT_DEAD                       0x00000010
106 #define EXIT_ZOMBIE                     0x00000020
107 #define EXIT_TRACE                      (EXIT_ZOMBIE | EXIT_DEAD)
108 /* Used in tsk->__state again: */
109 #define TASK_PARKED                     0x00000040
110 #define TASK_DEAD                       0x00000080
111 #define TASK_WAKEKILL                   0x00000100
112 #define TASK_WAKING                     0x00000200
113 #define TASK_NOLOAD                     0x00000400
114 #define TASK_NEW                        0x00000800
115 #define TASK_RTLOCK_WAIT                0x00001000
116 #define TASK_FREEZABLE                  0x00002000
117 #define __TASK_FREEZABLE_UNSAFE        (0x00004000 * IS_ENABLED(CONFIG_LOCKDEP))
118 #define TASK_FROZEN                     0x00008000
119 #define TASK_STATE_MAX                  0x00010000
120
121 #define TASK_ANY                        (TASK_STATE_MAX-1)
122
123 /*
124  * DO NOT ADD ANY NEW USERS !
125  */
126 #define TASK_FREEZABLE_UNSAFE           (TASK_FREEZABLE | __TASK_FREEZABLE_UNSAFE)
127
128 /* Convenience macros for the sake of set_current_state: */
129 #define TASK_KILLABLE                   (TASK_WAKEKILL | TASK_UNINTERRUPTIBLE)
130 #define TASK_STOPPED                    (TASK_WAKEKILL | __TASK_STOPPED)
131 #define TASK_TRACED                     __TASK_TRACED
132
133 #define TASK_IDLE                       (TASK_UNINTERRUPTIBLE | TASK_NOLOAD)
134
135 /* Convenience macros for the sake of wake_up(): */
136 #define TASK_NORMAL                     (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)
137
138 /* get_task_state(): */
139 #define TASK_REPORT                     (TASK_RUNNING | TASK_INTERRUPTIBLE | \
140                                          TASK_UNINTERRUPTIBLE | __TASK_STOPPED | \
141                                          __TASK_TRACED | EXIT_DEAD | EXIT_ZOMBIE | \
142                                          TASK_PARKED)
143
144 #define task_is_running(task)           (READ_ONCE((task)->__state) == TASK_RUNNING)
145
146 #define task_is_traced(task)            ((READ_ONCE(task->jobctl) & JOBCTL_TRACED) != 0)
147 #define task_is_stopped(task)           ((READ_ONCE(task->jobctl) & JOBCTL_STOPPED) != 0)
148 #define task_is_stopped_or_traced(task) ((READ_ONCE(task->jobctl) & (JOBCTL_STOPPED | JOBCTL_TRACED)) != 0)
149
150 /*
151  * Special states are those that do not use the normal wait-loop pattern. See
152  * the comment with set_special_state().
153  */
154 #define is_special_task_state(state)                                    \
155         ((state) & (__TASK_STOPPED | __TASK_TRACED | TASK_PARKED |      \
156                     TASK_DEAD | TASK_FROZEN))
157
158 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
159 # define debug_normal_state_change(state_value)                         \
160         do {                                                            \
161                 WARN_ON_ONCE(is_special_task_state(state_value));       \
162                 current->task_state_change = _THIS_IP_;                 \
163         } while (0)
164
165 # define debug_special_state_change(state_value)                        \
166         do {                                                            \
167                 WARN_ON_ONCE(!is_special_task_state(state_value));      \
168                 current->task_state_change = _THIS_IP_;                 \
169         } while (0)
170
171 # define debug_rtlock_wait_set_state()                                  \
172         do {                                                             \
173                 current->saved_state_change = current->task_state_change;\
174                 current->task_state_change = _THIS_IP_;                  \
175         } while (0)
176
177 # define debug_rtlock_wait_restore_state()                              \
178         do {                                                             \
179                 current->task_state_change = current->saved_state_change;\
180         } while (0)
181
182 #else
183 # define debug_normal_state_change(cond)        do { } while (0)
184 # define debug_special_state_change(cond)       do { } while (0)
185 # define debug_rtlock_wait_set_state()          do { } while (0)
186 # define debug_rtlock_wait_restore_state()      do { } while (0)
187 #endif
188
189 /*
190  * set_current_state() includes a barrier so that the write of current->__state
191  * is correctly serialised wrt the caller's subsequent test of whether to
192  * actually sleep:
193  *
194  *   for (;;) {
195  *      set_current_state(TASK_UNINTERRUPTIBLE);
196  *      if (CONDITION)
197  *         break;
198  *
199  *      schedule();
200  *   }
201  *   __set_current_state(TASK_RUNNING);
202  *
203  * If the caller does not need such serialisation (because, for instance, the
204  * CONDITION test and condition change and wakeup are under the same lock) then
205  * use __set_current_state().
206  *
207  * The above is typically ordered against the wakeup, which does:
208  *
209  *   CONDITION = 1;
210  *   wake_up_state(p, TASK_UNINTERRUPTIBLE);
211  *
212  * where wake_up_state()/try_to_wake_up() executes a full memory barrier before
213  * accessing p->__state.
214  *
215  * Wakeup will do: if (@state & p->__state) p->__state = TASK_RUNNING, that is,
216  * once it observes the TASK_UNINTERRUPTIBLE store the waking CPU can issue a
217  * TASK_RUNNING store which can collide with __set_current_state(TASK_RUNNING).
218  *
219  * However, with slightly different timing the wakeup TASK_RUNNING store can
220  * also collide with the TASK_UNINTERRUPTIBLE store. Losing that store is not
221  * a problem either because that will result in one extra go around the loop
222  * and our @cond test will save the day.
223  *
224  * Also see the comments of try_to_wake_up().
225  */
226 #define __set_current_state(state_value)                                \
227         do {                                                            \
228                 debug_normal_state_change((state_value));               \
229                 WRITE_ONCE(current->__state, (state_value));            \
230         } while (0)
231
232 #define set_current_state(state_value)                                  \
233         do {                                                            \
234                 debug_normal_state_change((state_value));               \
235                 smp_store_mb(current->__state, (state_value));          \
236         } while (0)
237
238 /*
239  * set_special_state() should be used for those states when the blocking task
240  * can not use the regular condition based wait-loop. In that case we must
241  * serialize against wakeups such that any possible in-flight TASK_RUNNING
242  * stores will not collide with our state change.
243  */
244 #define set_special_state(state_value)                                  \
245         do {                                                            \
246                 unsigned long flags; /* may shadow */                   \
247                                                                         \
248                 raw_spin_lock_irqsave(&current->pi_lock, flags);        \
249                 debug_special_state_change((state_value));              \
250                 WRITE_ONCE(current->__state, (state_value));            \
251                 raw_spin_unlock_irqrestore(&current->pi_lock, flags);   \
252         } while (0)
253
254 /*
255  * PREEMPT_RT specific variants for "sleeping" spin/rwlocks
256  *
257  * RT's spin/rwlock substitutions are state preserving. The state of the
258  * task when blocking on the lock is saved in task_struct::saved_state and
259  * restored after the lock has been acquired.  These operations are
260  * serialized by task_struct::pi_lock against try_to_wake_up(). Any non RT
261  * lock related wakeups while the task is blocked on the lock are
262  * redirected to operate on task_struct::saved_state to ensure that these
263  * are not dropped. On restore task_struct::saved_state is set to
264  * TASK_RUNNING so any wakeup attempt redirected to saved_state will fail.
265  *
266  * The lock operation looks like this:
267  *
268  *      current_save_and_set_rtlock_wait_state();
269  *      for (;;) {
270  *              if (try_lock())
271  *                      break;
272  *              raw_spin_unlock_irq(&lock->wait_lock);
273  *              schedule_rtlock();
274  *              raw_spin_lock_irq(&lock->wait_lock);
275  *              set_current_state(TASK_RTLOCK_WAIT);
276  *      }
277  *      current_restore_rtlock_saved_state();
278  */
279 #define current_save_and_set_rtlock_wait_state()                        \
280         do {                                                            \
281                 lockdep_assert_irqs_disabled();                         \
282                 raw_spin_lock(&current->pi_lock);                       \
283                 current->saved_state = current->__state;                \
284                 debug_rtlock_wait_set_state();                          \
285                 WRITE_ONCE(current->__state, TASK_RTLOCK_WAIT);         \
286                 raw_spin_unlock(&current->pi_lock);                     \
287         } while (0);
288
289 #define current_restore_rtlock_saved_state()                            \
290         do {                                                            \
291                 lockdep_assert_irqs_disabled();                         \
292                 raw_spin_lock(&current->pi_lock);                       \
293                 debug_rtlock_wait_restore_state();                      \
294                 WRITE_ONCE(current->__state, current->saved_state);     \
295                 current->saved_state = TASK_RUNNING;                    \
296                 raw_spin_unlock(&current->pi_lock);                     \
297         } while (0);
298
299 #define get_current_state()     READ_ONCE(current->__state)
300
301 /*
302  * Define the task command name length as enum, then it can be visible to
303  * BPF programs.
304  */
305 enum {
306         TASK_COMM_LEN = 16,
307 };
308
309 extern void sched_tick(void);
310
311 #define MAX_SCHEDULE_TIMEOUT            LONG_MAX
312
313 extern long schedule_timeout(long timeout);
314 extern long schedule_timeout_interruptible(long timeout);
315 extern long schedule_timeout_killable(long timeout);
316 extern long schedule_timeout_uninterruptible(long timeout);
317 extern long schedule_timeout_idle(long timeout);
318 asmlinkage void schedule(void);
319 extern void schedule_preempt_disabled(void);
320 asmlinkage void preempt_schedule_irq(void);
321 #ifdef CONFIG_PREEMPT_RT
322  extern void schedule_rtlock(void);
323 #endif
324
325 extern int __must_check io_schedule_prepare(void);
326 extern void io_schedule_finish(int token);
327 extern long io_schedule_timeout(long timeout);
328 extern void io_schedule(void);
329
330 /**
331  * struct prev_cputime - snapshot of system and user cputime
332  * @utime: time spent in user mode
333  * @stime: time spent in system mode
334  * @lock: protects the above two fields
335  *
336  * Stores previous user/system time values such that we can guarantee
337  * monotonicity.
338  */
339 struct prev_cputime {
340 #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
341         u64                             utime;
342         u64                             stime;
343         raw_spinlock_t                  lock;
344 #endif
345 };
346
347 enum vtime_state {
348         /* Task is sleeping or running in a CPU with VTIME inactive: */
349         VTIME_INACTIVE = 0,
350         /* Task is idle */
351         VTIME_IDLE,
352         /* Task runs in kernelspace in a CPU with VTIME active: */
353         VTIME_SYS,
354         /* Task runs in userspace in a CPU with VTIME active: */
355         VTIME_USER,
356         /* Task runs as guests in a CPU with VTIME active: */
357         VTIME_GUEST,
358 };
359
360 struct vtime {
361         seqcount_t              seqcount;
362         unsigned long long      starttime;
363         enum vtime_state        state;
364         unsigned int            cpu;
365         u64                     utime;
366         u64                     stime;
367         u64                     gtime;
368 };
369
370 /*
371  * Utilization clamp constraints.
372  * @UCLAMP_MIN: Minimum utilization
373  * @UCLAMP_MAX: Maximum utilization
374  * @UCLAMP_CNT: Utilization clamp constraints count
375  */
376 enum uclamp_id {
377         UCLAMP_MIN = 0,
378         UCLAMP_MAX,
379         UCLAMP_CNT
380 };
381
382 #ifdef CONFIG_SMP
383 extern struct root_domain def_root_domain;
384 extern struct mutex sched_domains_mutex;
385 #endif
386
387 struct sched_param {
388         int sched_priority;
389 };
390
391 struct sched_info {
392 #ifdef CONFIG_SCHED_INFO
393         /* Cumulative counters: */
394
395         /* # of times we have run on this CPU: */
396         unsigned long                   pcount;
397
398         /* Time spent waiting on a runqueue: */
399         unsigned long long              run_delay;
400
401         /* Timestamps: */
402
403         /* When did we last run on a CPU? */
404         unsigned long long              last_arrival;
405
406         /* When were we last queued to run? */
407         unsigned long long              last_queued;
408
409 #endif /* CONFIG_SCHED_INFO */
410 };
411
412 /*
413  * Integer metrics need fixed point arithmetic, e.g., sched/fair
414  * has a few: load, load_avg, util_avg, freq, and capacity.
415  *
416  * We define a basic fixed point arithmetic range, and then formalize
417  * all these metrics based on that basic range.
418  */
419 # define SCHED_FIXEDPOINT_SHIFT         10
420 # define SCHED_FIXEDPOINT_SCALE         (1L << SCHED_FIXEDPOINT_SHIFT)
421
422 /* Increase resolution of cpu_capacity calculations */
423 # define SCHED_CAPACITY_SHIFT           SCHED_FIXEDPOINT_SHIFT
424 # define SCHED_CAPACITY_SCALE           (1L << SCHED_CAPACITY_SHIFT)
425
426 struct load_weight {
427         unsigned long                   weight;
428         u32                             inv_weight;
429 };
430
431 /*
432  * The load/runnable/util_avg accumulates an infinite geometric series
433  * (see __update_load_avg_cfs_rq() in kernel/sched/pelt.c).
434  *
435  * [load_avg definition]
436  *
437  *   load_avg = runnable% * scale_load_down(load)
438  *
439  * [runnable_avg definition]
440  *
441  *   runnable_avg = runnable% * SCHED_CAPACITY_SCALE
442  *
443  * [util_avg definition]
444  *
445  *   util_avg = running% * SCHED_CAPACITY_SCALE
446  *
447  * where runnable% is the time ratio that a sched_entity is runnable and
448  * running% the time ratio that a sched_entity is running.
449  *
450  * For cfs_rq, they are the aggregated values of all runnable and blocked
451  * sched_entities.
452  *
453  * The load/runnable/util_avg doesn't directly factor frequency scaling and CPU
454  * capacity scaling. The scaling is done through the rq_clock_pelt that is used
455  * for computing those signals (see update_rq_clock_pelt())
456  *
457  * N.B., the above ratios (runnable% and running%) themselves are in the
458  * range of [0, 1]. To do fixed point arithmetics, we therefore scale them
459  * to as large a range as necessary. This is for example reflected by
460  * util_avg's SCHED_CAPACITY_SCALE.
461  *
462  * [Overflow issue]
463  *
464  * The 64-bit load_sum can have 4353082796 (=2^64/47742/88761) entities
465  * with the highest load (=88761), always runnable on a single cfs_rq,
466  * and should not overflow as the number already hits PID_MAX_LIMIT.
467  *
468  * For all other cases (including 32-bit kernels), struct load_weight's
469  * weight will overflow first before we do, because:
470  *
471  *    Max(load_avg) <= Max(load.weight)
472  *
473  * Then it is the load_weight's responsibility to consider overflow
474  * issues.
475  */
476 struct sched_avg {
477         u64                             last_update_time;
478         u64                             load_sum;
479         u64                             runnable_sum;
480         u32                             util_sum;
481         u32                             period_contrib;
482         unsigned long                   load_avg;
483         unsigned long                   runnable_avg;
484         unsigned long                   util_avg;
485         unsigned int                    util_est;
486 } ____cacheline_aligned;
487
488 /*
489  * The UTIL_AVG_UNCHANGED flag is used to synchronize util_est with util_avg
490  * updates. When a task is dequeued, its util_est should not be updated if its
491  * util_avg has not been updated in the meantime.
492  * This information is mapped into the MSB bit of util_est at dequeue time.
493  * Since max value of util_est for a task is 1024 (PELT util_avg for a task)
494  * it is safe to use MSB.
495  */
496 #define UTIL_EST_WEIGHT_SHIFT           2
497 #define UTIL_AVG_UNCHANGED              0x80000000
498
499 struct sched_statistics {
500 #ifdef CONFIG_SCHEDSTATS
501         u64                             wait_start;
502         u64                             wait_max;
503         u64                             wait_count;
504         u64                             wait_sum;
505         u64                             iowait_count;
506         u64                             iowait_sum;
507
508         u64                             sleep_start;
509         u64                             sleep_max;
510         s64                             sum_sleep_runtime;
511
512         u64                             block_start;
513         u64                             block_max;
514         s64                             sum_block_runtime;
515
516         s64                             exec_max;
517         u64                             slice_max;
518
519         u64                             nr_migrations_cold;
520         u64                             nr_failed_migrations_affine;
521         u64                             nr_failed_migrations_running;
522         u64                             nr_failed_migrations_hot;
523         u64                             nr_forced_migrations;
524
525         u64                             nr_wakeups;
526         u64                             nr_wakeups_sync;
527         u64                             nr_wakeups_migrate;
528         u64                             nr_wakeups_local;
529         u64                             nr_wakeups_remote;
530         u64                             nr_wakeups_affine;
531         u64                             nr_wakeups_affine_attempts;
532         u64                             nr_wakeups_passive;
533         u64                             nr_wakeups_idle;
534
535 #ifdef CONFIG_SCHED_CORE
536         u64                             core_forceidle_sum;
537 #endif
538 #endif /* CONFIG_SCHEDSTATS */
539 } ____cacheline_aligned;
540
541 struct sched_entity {
542         /* For load-balancing: */
543         struct load_weight              load;
544         struct rb_node                  run_node;
545         u64                             deadline;
546         u64                             min_vruntime;
547         u64                             min_slice;
548
549         struct list_head                group_node;
550         unsigned char                   on_rq;
551         unsigned char                   sched_delayed;
552         unsigned char                   rel_deadline;
553         unsigned char                   custom_slice;
554                                         /* hole */
555
556         u64                             exec_start;
557         u64                             sum_exec_runtime;
558         u64                             prev_sum_exec_runtime;
559         u64                             vruntime;
560         s64                             vlag;
561         u64                             slice;
562
563         u64                             nr_migrations;
564
565 #ifdef CONFIG_FAIR_GROUP_SCHED
566         int                             depth;
567         struct sched_entity             *parent;
568         /* rq on which this entity is (to be) queued: */
569         struct cfs_rq                   *cfs_rq;
570         /* rq "owned" by this entity/group: */
571         struct cfs_rq                   *my_q;
572         /* cached value of my_q->h_nr_running */
573         unsigned long                   runnable_weight;
574 #endif
575
576 #ifdef CONFIG_SMP
577         /*
578          * Per entity load average tracking.
579          *
580          * Put into separate cache line so it does not
581          * collide with read-mostly values above.
582          */
583         struct sched_avg                avg;
584 #endif
585 };
586
587 struct sched_rt_entity {
588         struct list_head                run_list;
589         unsigned long                   timeout;
590         unsigned long                   watchdog_stamp;
591         unsigned int                    time_slice;
592         unsigned short                  on_rq;
593         unsigned short                  on_list;
594
595         struct sched_rt_entity          *back;
596 #ifdef CONFIG_RT_GROUP_SCHED
597         struct sched_rt_entity          *parent;
598         /* rq on which this entity is (to be) queued: */
599         struct rt_rq                    *rt_rq;
600         /* rq "owned" by this entity/group: */
601         struct rt_rq                    *my_q;
602 #endif
603 } __randomize_layout;
604
605 typedef bool (*dl_server_has_tasks_f)(struct sched_dl_entity *);
606 typedef struct task_struct *(*dl_server_pick_f)(struct sched_dl_entity *);
607
608 struct sched_dl_entity {
609         struct rb_node                  rb_node;
610
611         /*
612          * Original scheduling parameters. Copied here from sched_attr
613          * during sched_setattr(), they will remain the same until
614          * the next sched_setattr().
615          */
616         u64                             dl_runtime;     /* Maximum runtime for each instance    */
617         u64                             dl_deadline;    /* Relative deadline of each instance   */
618         u64                             dl_period;      /* Separation of two instances (period) */
619         u64                             dl_bw;          /* dl_runtime / dl_period               */
620         u64                             dl_density;     /* dl_runtime / dl_deadline             */
621
622         /*
623          * Actual scheduling parameters. Initialized with the values above,
624          * they are continuously updated during task execution. Note that
625          * the remaining runtime could be < 0 in case we are in overrun.
626          */
627         s64                             runtime;        /* Remaining runtime for this instance  */
628         u64                             deadline;       /* Absolute deadline for this instance  */
629         unsigned int                    flags;          /* Specifying the scheduler behaviour   */
630
631         /*
632          * Some bool flags:
633          *
634          * @dl_throttled tells if we exhausted the runtime. If so, the
635          * task has to wait for a replenishment to be performed at the
636          * next firing of dl_timer.
637          *
638          * @dl_yielded tells if task gave up the CPU before consuming
639          * all its available runtime during the last job.
640          *
641          * @dl_non_contending tells if the task is inactive while still
642          * contributing to the active utilization. In other words, it
643          * indicates if the inactive timer has been armed and its handler
644          * has not been executed yet. This flag is useful to avoid race
645          * conditions between the inactive timer handler and the wakeup
646          * code.
647          *
648          * @dl_overrun tells if the task asked to be informed about runtime
649          * overruns.
650          *
651          * @dl_server tells if this is a server entity.
652          *
653          * @dl_defer tells if this is a deferred or regular server. For
654          * now only defer server exists.
655          *
656          * @dl_defer_armed tells if the deferrable server is waiting
657          * for the replenishment timer to activate it.
658          *
659          * @dl_defer_running tells if the deferrable server is actually
660          * running, skipping the defer phase.
661          */
662         unsigned int                    dl_throttled      : 1;
663         unsigned int                    dl_yielded        : 1;
664         unsigned int                    dl_non_contending : 1;
665         unsigned int                    dl_overrun        : 1;
666         unsigned int                    dl_server         : 1;
667         unsigned int                    dl_defer          : 1;
668         unsigned int                    dl_defer_armed    : 1;
669         unsigned int                    dl_defer_running  : 1;
670
671         /*
672          * Bandwidth enforcement timer. Each -deadline task has its
673          * own bandwidth to be enforced, thus we need one timer per task.
674          */
675         struct hrtimer                  dl_timer;
676
677         /*
678          * Inactive timer, responsible for decreasing the active utilization
679          * at the "0-lag time". When a -deadline task blocks, it contributes
680          * to GRUB's active utilization until the "0-lag time", hence a
681          * timer is needed to decrease the active utilization at the correct
682          * time.
683          */
684         struct hrtimer                  inactive_timer;
685
686         /*
687          * Bits for DL-server functionality. Also see the comment near
688          * dl_server_update().
689          *
690          * @rq the runqueue this server is for
691          *
692          * @server_has_tasks() returns true if @server_pick return a
693          * runnable task.
694          */
695         struct rq                       *rq;
696         dl_server_has_tasks_f           server_has_tasks;
697         dl_server_pick_f                server_pick_task;
698
699 #ifdef CONFIG_RT_MUTEXES
700         /*
701          * Priority Inheritance. When a DEADLINE scheduling entity is boosted
702          * pi_se points to the donor, otherwise points to the dl_se it belongs
703          * to (the original one/itself).
704          */
705         struct sched_dl_entity *pi_se;
706 #endif
707 };
708
709 #ifdef CONFIG_UCLAMP_TASK
710 /* Number of utilization clamp buckets (shorter alias) */
711 #define UCLAMP_BUCKETS CONFIG_UCLAMP_BUCKETS_COUNT
712
713 /*
714  * Utilization clamp for a scheduling entity
715  * @value:              clamp value "assigned" to a se
716  * @bucket_id:          bucket index corresponding to the "assigned" value
717  * @active:             the se is currently refcounted in a rq's bucket
718  * @user_defined:       the requested clamp value comes from user-space
719  *
720  * The bucket_id is the index of the clamp bucket matching the clamp value
721  * which is pre-computed and stored to avoid expensive integer divisions from
722  * the fast path.
723  *
724  * The active bit is set whenever a task has got an "effective" value assigned,
725  * which can be different from the clamp value "requested" from user-space.
726  * This allows to know a task is refcounted in the rq's bucket corresponding
727  * to the "effective" bucket_id.
728  *
729  * The user_defined bit is set whenever a task has got a task-specific clamp
730  * value requested from userspace, i.e. the system defaults apply to this task
731  * just as a restriction. This allows to relax default clamps when a less
732  * restrictive task-specific value has been requested, thus allowing to
733  * implement a "nice" semantic. For example, a task running with a 20%
734  * default boost can still drop its own boosting to 0%.
735  */
736 struct uclamp_se {
737         unsigned int value              : bits_per(SCHED_CAPACITY_SCALE);
738         unsigned int bucket_id          : bits_per(UCLAMP_BUCKETS);
739         unsigned int active             : 1;
740         unsigned int user_defined       : 1;
741 };
742 #endif /* CONFIG_UCLAMP_TASK */
743
744 union rcu_special {
745         struct {
746                 u8                      blocked;
747                 u8                      need_qs;
748                 u8                      exp_hint; /* Hint for performance. */
749                 u8                      need_mb; /* Readers need smp_mb(). */
750         } b; /* Bits. */
751         u32 s; /* Set of bits. */
752 };
753
754 enum perf_event_task_context {
755         perf_invalid_context = -1,
756         perf_hw_context = 0,
757         perf_sw_context,
758         perf_nr_task_contexts,
759 };
760
761 /*
762  * Number of contexts where an event can trigger:
763  *      task, softirq, hardirq, nmi.
764  */
765 #define PERF_NR_CONTEXTS        4
766
767 struct wake_q_node {
768         struct wake_q_node *next;
769 };
770
771 struct kmap_ctrl {
772 #ifdef CONFIG_KMAP_LOCAL
773         int                             idx;
774         pte_t                           pteval[KM_MAX_IDX];
775 #endif
776 };
777
778 struct task_struct {
779 #ifdef CONFIG_THREAD_INFO_IN_TASK
780         /*
781          * For reasons of header soup (see current_thread_info()), this
782          * must be the first element of task_struct.
783          */
784         struct thread_info              thread_info;
785 #endif
786         unsigned int                    __state;
787
788         /* saved state for "spinlock sleepers" */
789         unsigned int                    saved_state;
790
791         /*
792          * This begins the randomizable portion of task_struct. Only
793          * scheduling-critical items should be added above here.
794          */
795         randomized_struct_fields_start
796
797         void                            *stack;
798         refcount_t                      usage;
799         /* Per task flags (PF_*), defined further below: */
800         unsigned int                    flags;
801         unsigned int                    ptrace;
802
803 #ifdef CONFIG_MEM_ALLOC_PROFILING
804         struct alloc_tag                *alloc_tag;
805 #endif
806
807 #ifdef CONFIG_SMP
808         int                             on_cpu;
809         struct __call_single_node       wake_entry;
810         unsigned int                    wakee_flips;
811         unsigned long                   wakee_flip_decay_ts;
812         struct task_struct              *last_wakee;
813
814         /*
815          * recent_used_cpu is initially set as the last CPU used by a task
816          * that wakes affine another task. Waker/wakee relationships can
817          * push tasks around a CPU where each wakeup moves to the next one.
818          * Tracking a recently used CPU allows a quick search for a recently
819          * used CPU that may be idle.
820          */
821         int                             recent_used_cpu;
822         int                             wake_cpu;
823 #endif
824         int                             on_rq;
825
826         int                             prio;
827         int                             static_prio;
828         int                             normal_prio;
829         unsigned int                    rt_priority;
830
831         struct sched_entity             se;
832         struct sched_rt_entity          rt;
833         struct sched_dl_entity          dl;
834         struct sched_dl_entity          *dl_server;
835 #ifdef CONFIG_SCHED_CLASS_EXT
836         struct sched_ext_entity         scx;
837 #endif
838         const struct sched_class        *sched_class;
839
840 #ifdef CONFIG_SCHED_CORE
841         struct rb_node                  core_node;
842         unsigned long                   core_cookie;
843         unsigned int                    core_occupation;
844 #endif
845
846 #ifdef CONFIG_CGROUP_SCHED
847         struct task_group               *sched_task_group;
848 #endif
849
850
851 #ifdef CONFIG_UCLAMP_TASK
852         /*
853          * Clamp values requested for a scheduling entity.
854          * Must be updated with task_rq_lock() held.
855          */
856         struct uclamp_se                uclamp_req[UCLAMP_CNT];
857         /*
858          * Effective clamp values used for a scheduling entity.
859          * Must be updated with task_rq_lock() held.
860          */
861         struct uclamp_se                uclamp[UCLAMP_CNT];
862 #endif
863
864         struct sched_statistics         stats;
865
866 #ifdef CONFIG_PREEMPT_NOTIFIERS
867         /* List of struct preempt_notifier: */
868         struct hlist_head               preempt_notifiers;
869 #endif
870
871 #ifdef CONFIG_BLK_DEV_IO_TRACE
872         unsigned int                    btrace_seq;
873 #endif
874
875         unsigned int                    policy;
876         unsigned long                   max_allowed_capacity;
877         int                             nr_cpus_allowed;
878         const cpumask_t                 *cpus_ptr;
879         cpumask_t                       *user_cpus_ptr;
880         cpumask_t                       cpus_mask;
881         void                            *migration_pending;
882 #ifdef CONFIG_SMP
883         unsigned short                  migration_disabled;
884 #endif
885         unsigned short                  migration_flags;
886
887 #ifdef CONFIG_PREEMPT_RCU
888         int                             rcu_read_lock_nesting;
889         union rcu_special               rcu_read_unlock_special;
890         struct list_head                rcu_node_entry;
891         struct rcu_node                 *rcu_blocked_node;
892 #endif /* #ifdef CONFIG_PREEMPT_RCU */
893
894 #ifdef CONFIG_TASKS_RCU
895         unsigned long                   rcu_tasks_nvcsw;
896         u8                              rcu_tasks_holdout;
897         u8                              rcu_tasks_idx;
898         int                             rcu_tasks_idle_cpu;
899         struct list_head                rcu_tasks_holdout_list;
900         int                             rcu_tasks_exit_cpu;
901         struct list_head                rcu_tasks_exit_list;
902 #endif /* #ifdef CONFIG_TASKS_RCU */
903
904 #ifdef CONFIG_TASKS_TRACE_RCU
905         int                             trc_reader_nesting;
906         int                             trc_ipi_to_cpu;
907         union rcu_special               trc_reader_special;
908         struct list_head                trc_holdout_list;
909         struct list_head                trc_blkd_node;
910         int                             trc_blkd_cpu;
911 #endif /* #ifdef CONFIG_TASKS_TRACE_RCU */
912
913         struct sched_info               sched_info;
914
915         struct list_head                tasks;
916 #ifdef CONFIG_SMP
917         struct plist_node               pushable_tasks;
918         struct rb_node                  pushable_dl_tasks;
919 #endif
920
921         struct mm_struct                *mm;
922         struct mm_struct                *active_mm;
923         struct address_space            *faults_disabled_mapping;
924
925         int                             exit_state;
926         int                             exit_code;
927         int                             exit_signal;
928         /* The signal sent when the parent dies: */
929         int                             pdeath_signal;
930         /* JOBCTL_*, siglock protected: */
931         unsigned long                   jobctl;
932
933         /* Used for emulating ABI behavior of previous Linux versions: */
934         unsigned int                    personality;
935
936         /* Scheduler bits, serialized by scheduler locks: */
937         unsigned                        sched_reset_on_fork:1;
938         unsigned                        sched_contributes_to_load:1;
939         unsigned                        sched_migrated:1;
940
941         /* Force alignment to the next boundary: */
942         unsigned                        :0;
943
944         /* Unserialized, strictly 'current' */
945
946         /*
947          * This field must not be in the scheduler word above due to wakelist
948          * queueing no longer being serialized by p->on_cpu. However:
949          *
950          * p->XXX = X;                  ttwu()
951          * schedule()                     if (p->on_rq && ..) // false
952          *   smp_mb__after_spinlock();    if (smp_load_acquire(&p->on_cpu) && //true
953          *   deactivate_task()                ttwu_queue_wakelist())
954          *     p->on_rq = 0;                    p->sched_remote_wakeup = Y;
955          *
956          * guarantees all stores of 'current' are visible before
957          * ->sched_remote_wakeup gets used, so it can be in this word.
958          */
959         unsigned                        sched_remote_wakeup:1;
960 #ifdef CONFIG_RT_MUTEXES
961         unsigned                        sched_rt_mutex:1;
962 #endif
963
964         /* Bit to tell TOMOYO we're in execve(): */
965         unsigned                        in_execve:1;
966         unsigned                        in_iowait:1;
967 #ifndef TIF_RESTORE_SIGMASK
968         unsigned                        restore_sigmask:1;
969 #endif
970 #ifdef CONFIG_MEMCG_V1
971         unsigned                        in_user_fault:1;
972 #endif
973 #ifdef CONFIG_LRU_GEN
974         /* whether the LRU algorithm may apply to this access */
975         unsigned                        in_lru_fault:1;
976 #endif
977 #ifdef CONFIG_COMPAT_BRK
978         unsigned                        brk_randomized:1;
979 #endif
980 #ifdef CONFIG_CGROUPS
981         /* disallow userland-initiated cgroup migration */
982         unsigned                        no_cgroup_migration:1;
983         /* task is frozen/stopped (used by the cgroup freezer) */
984         unsigned                        frozen:1;
985 #endif
986 #ifdef CONFIG_BLK_CGROUP
987         unsigned                        use_memdelay:1;
988 #endif
989 #ifdef CONFIG_PSI
990         /* Stalled due to lack of memory */
991         unsigned                        in_memstall:1;
992 #endif
993 #ifdef CONFIG_PAGE_OWNER
994         /* Used by page_owner=on to detect recursion in page tracking. */
995         unsigned                        in_page_owner:1;
996 #endif
997 #ifdef CONFIG_EVENTFD
998         /* Recursion prevention for eventfd_signal() */
999         unsigned                        in_eventfd:1;
1000 #endif
1001 #ifdef CONFIG_ARCH_HAS_CPU_PASID
1002         unsigned                        pasid_activated:1;
1003 #endif
1004 #ifdef  CONFIG_CPU_SUP_INTEL
1005         unsigned                        reported_split_lock:1;
1006 #endif
1007 #ifdef CONFIG_TASK_DELAY_ACCT
1008         /* delay due to memory thrashing */
1009         unsigned                        in_thrashing:1;
1010 #endif
1011 #ifdef CONFIG_PREEMPT_RT
1012         struct netdev_xmit              net_xmit;
1013 #endif
1014         unsigned long                   atomic_flags; /* Flags requiring atomic access. */
1015
1016         struct restart_block            restart_block;
1017
1018         pid_t                           pid;
1019         pid_t                           tgid;
1020
1021 #ifdef CONFIG_STACKPROTECTOR
1022         /* Canary value for the -fstack-protector GCC feature: */
1023         unsigned long                   stack_canary;
1024 #endif
1025         /*
1026          * Pointers to the (original) parent process, youngest child, younger sibling,
1027          * older sibling, respectively.  (p->father can be replaced with
1028          * p->real_parent->pid)
1029          */
1030
1031         /* Real parent process: */
1032         struct task_struct __rcu        *real_parent;
1033
1034         /* Recipient of SIGCHLD, wait4() reports: */
1035         struct task_struct __rcu        *parent;
1036
1037         /*
1038          * Children/sibling form the list of natural children:
1039          */
1040         struct list_head                children;
1041         struct list_head                sibling;
1042         struct task_struct              *group_leader;
1043
1044         /*
1045          * 'ptraced' is the list of tasks this task is using ptrace() on.
1046          *
1047          * This includes both natural children and PTRACE_ATTACH targets.
1048          * 'ptrace_entry' is this task's link on the p->parent->ptraced list.
1049          */
1050         struct list_head                ptraced;
1051         struct list_head                ptrace_entry;
1052
1053         /* PID/PID hash table linkage. */
1054         struct pid                      *thread_pid;
1055         struct hlist_node               pid_links[PIDTYPE_MAX];
1056         struct list_head                thread_node;
1057
1058         struct completion               *vfork_done;
1059
1060         /* CLONE_CHILD_SETTID: */
1061         int __user                      *set_child_tid;
1062
1063         /* CLONE_CHILD_CLEARTID: */
1064         int __user                      *clear_child_tid;
1065
1066         /* PF_KTHREAD | PF_IO_WORKER */
1067         void                            *worker_private;
1068
1069         u64                             utime;
1070         u64                             stime;
1071 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
1072         u64                             utimescaled;
1073         u64                             stimescaled;
1074 #endif
1075         u64                             gtime;
1076         struct prev_cputime             prev_cputime;
1077 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
1078         struct vtime                    vtime;
1079 #endif
1080
1081 #ifdef CONFIG_NO_HZ_FULL
1082         atomic_t                        tick_dep_mask;
1083 #endif
1084         /* Context switch counts: */
1085         unsigned long                   nvcsw;
1086         unsigned long                   nivcsw;
1087
1088         /* Monotonic time in nsecs: */
1089         u64                             start_time;
1090
1091         /* Boot based time in nsecs: */
1092         u64                             start_boottime;
1093
1094         /* MM fault and swap info: this can arguably be seen as either mm-specific or thread-specific: */
1095         unsigned long                   min_flt;
1096         unsigned long                   maj_flt;
1097
1098         /* Empty if CONFIG_POSIX_CPUTIMERS=n */
1099         struct posix_cputimers          posix_cputimers;
1100
1101 #ifdef CONFIG_POSIX_CPU_TIMERS_TASK_WORK
1102         struct posix_cputimers_work     posix_cputimers_work;
1103 #endif
1104
1105         /* Process credentials: */
1106
1107         /* Tracer's credentials at attach: */
1108         const struct cred __rcu         *ptracer_cred;
1109
1110         /* Objective and real subjective task credentials (COW): */
1111         const struct cred __rcu         *real_cred;
1112
1113         /* Effective (overridable) subjective task credentials (COW): */
1114         const struct cred __rcu         *cred;
1115
1116 #ifdef CONFIG_KEYS
1117         /* Cached requested key. */
1118         struct key                      *cached_requested_key;
1119 #endif
1120
1121         /*
1122          * executable name, excluding path.
1123          *
1124          * - normally initialized setup_new_exec()
1125          * - access it with [gs]et_task_comm()
1126          * - lock it with task_lock()
1127          */
1128         char                            comm[TASK_COMM_LEN];
1129
1130         struct nameidata                *nameidata;
1131
1132 #ifdef CONFIG_SYSVIPC
1133         struct sysv_sem                 sysvsem;
1134         struct sysv_shm                 sysvshm;
1135 #endif
1136 #ifdef CONFIG_DETECT_HUNG_TASK
1137         unsigned long                   last_switch_count;
1138         unsigned long                   last_switch_time;
1139 #endif
1140         /* Filesystem information: */
1141         struct fs_struct                *fs;
1142
1143         /* Open file information: */
1144         struct files_struct             *files;
1145
1146 #ifdef CONFIG_IO_URING
1147         struct io_uring_task            *io_uring;
1148 #endif
1149
1150         /* Namespaces: */
1151         struct nsproxy                  *nsproxy;
1152
1153         /* Signal handlers: */
1154         struct signal_struct            *signal;
1155         struct sighand_struct __rcu             *sighand;
1156         sigset_t                        blocked;
1157         sigset_t                        real_blocked;
1158         /* Restored if set_restore_sigmask() was used: */
1159         sigset_t                        saved_sigmask;
1160         struct sigpending               pending;
1161         unsigned long                   sas_ss_sp;
1162         size_t                          sas_ss_size;
1163         unsigned int                    sas_ss_flags;
1164
1165         struct callback_head            *task_works;
1166
1167 #ifdef CONFIG_AUDIT
1168 #ifdef CONFIG_AUDITSYSCALL
1169         struct audit_context            *audit_context;
1170 #endif
1171         kuid_t                          loginuid;
1172         unsigned int                    sessionid;
1173 #endif
1174         struct seccomp                  seccomp;
1175         struct syscall_user_dispatch    syscall_dispatch;
1176
1177         /* Thread group tracking: */
1178         u64                             parent_exec_id;
1179         u64                             self_exec_id;
1180
1181         /* Protection against (de-)allocation: mm, files, fs, tty, keyrings, mems_allowed, mempolicy: */
1182         spinlock_t                      alloc_lock;
1183
1184         /* Protection of the PI data structures: */
1185         raw_spinlock_t                  pi_lock;
1186
1187         struct wake_q_node              wake_q;
1188
1189 #ifdef CONFIG_RT_MUTEXES
1190         /* PI waiters blocked on a rt_mutex held by this task: */
1191         struct rb_root_cached           pi_waiters;
1192         /* Updated under owner's pi_lock and rq lock */
1193         struct task_struct              *pi_top_task;
1194         /* Deadlock detection and priority inheritance handling: */
1195         struct rt_mutex_waiter          *pi_blocked_on;
1196 #endif
1197
1198 #ifdef CONFIG_DEBUG_MUTEXES
1199         /* Mutex deadlock detection: */
1200         struct mutex_waiter             *blocked_on;
1201 #endif
1202
1203 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
1204         int                             non_block_count;
1205 #endif
1206
1207 #ifdef CONFIG_TRACE_IRQFLAGS
1208         struct irqtrace_events          irqtrace;
1209         unsigned int                    hardirq_threaded;
1210         u64                             hardirq_chain_key;
1211         int                             softirqs_enabled;
1212         int                             softirq_context;
1213         int                             irq_config;
1214 #endif
1215 #ifdef CONFIG_PREEMPT_RT
1216         int                             softirq_disable_cnt;
1217 #endif
1218
1219 #ifdef CONFIG_LOCKDEP
1220 # define MAX_LOCK_DEPTH                 48UL
1221         u64                             curr_chain_key;
1222         int                             lockdep_depth;
1223         unsigned int                    lockdep_recursion;
1224         struct held_lock                held_locks[MAX_LOCK_DEPTH];
1225 #endif
1226
1227 #if defined(CONFIG_UBSAN) && !defined(CONFIG_UBSAN_TRAP)
1228         unsigned int                    in_ubsan;
1229 #endif
1230
1231         /* Journalling filesystem info: */
1232         void                            *journal_info;
1233
1234         /* Stacked block device info: */
1235         struct bio_list                 *bio_list;
1236
1237         /* Stack plugging: */
1238         struct blk_plug                 *plug;
1239
1240         /* VM state: */
1241         struct reclaim_state            *reclaim_state;
1242
1243         struct io_context               *io_context;
1244
1245 #ifdef CONFIG_COMPACTION
1246         struct capture_control          *capture_control;
1247 #endif
1248         /* Ptrace state: */
1249         unsigned long                   ptrace_message;
1250         kernel_siginfo_t                *last_siginfo;
1251
1252         struct task_io_accounting       ioac;
1253 #ifdef CONFIG_PSI
1254         /* Pressure stall state */
1255         unsigned int                    psi_flags;
1256 #endif
1257 #ifdef CONFIG_TASK_XACCT
1258         /* Accumulated RSS usage: */
1259         u64                             acct_rss_mem1;
1260         /* Accumulated virtual memory usage: */
1261         u64                             acct_vm_mem1;
1262         /* stime + utime since last update: */
1263         u64                             acct_timexpd;
1264 #endif
1265 #ifdef CONFIG_CPUSETS
1266         /* Protected by ->alloc_lock: */
1267         nodemask_t                      mems_allowed;
1268         /* Sequence number to catch updates: */
1269         seqcount_spinlock_t             mems_allowed_seq;
1270         int                             cpuset_mem_spread_rotor;
1271 #endif
1272 #ifdef CONFIG_CGROUPS
1273         /* Control Group info protected by css_set_lock: */
1274         struct css_set __rcu            *cgroups;
1275         /* cg_list protected by css_set_lock and tsk->alloc_lock: */
1276         struct list_head                cg_list;
1277 #endif
1278 #ifdef CONFIG_X86_CPU_RESCTRL
1279         u32                             closid;
1280         u32                             rmid;
1281 #endif
1282 #ifdef CONFIG_FUTEX
1283         struct robust_list_head __user  *robust_list;
1284 #ifdef CONFIG_COMPAT
1285         struct compat_robust_list_head __user *compat_robust_list;
1286 #endif
1287         struct list_head                pi_state_list;
1288         struct futex_pi_state           *pi_state_cache;
1289         struct mutex                    futex_exit_mutex;
1290         unsigned int                    futex_state;
1291 #endif
1292 #ifdef CONFIG_PERF_EVENTS
1293         u8                              perf_recursion[PERF_NR_CONTEXTS];
1294         struct perf_event_context       *perf_event_ctxp;
1295         struct mutex                    perf_event_mutex;
1296         struct list_head                perf_event_list;
1297 #endif
1298 #ifdef CONFIG_DEBUG_PREEMPT
1299         unsigned long                   preempt_disable_ip;
1300 #endif
1301 #ifdef CONFIG_NUMA
1302         /* Protected by alloc_lock: */
1303         struct mempolicy                *mempolicy;
1304         short                           il_prev;
1305         u8                              il_weight;
1306         short                           pref_node_fork;
1307 #endif
1308 #ifdef CONFIG_NUMA_BALANCING
1309         int                             numa_scan_seq;
1310         unsigned int                    numa_scan_period;
1311         unsigned int                    numa_scan_period_max;
1312         int                             numa_preferred_nid;
1313         unsigned long                   numa_migrate_retry;
1314         /* Migration stamp: */
1315         u64                             node_stamp;
1316         u64                             last_task_numa_placement;
1317         u64                             last_sum_exec_runtime;
1318         struct callback_head            numa_work;
1319
1320         /*
1321          * This pointer is only modified for current in syscall and
1322          * pagefault context (and for tasks being destroyed), so it can be read
1323          * from any of the following contexts:
1324          *  - RCU read-side critical section
1325          *  - current->numa_group from everywhere
1326          *  - task's runqueue locked, task not running
1327          */
1328         struct numa_group __rcu         *numa_group;
1329
1330         /*
1331          * numa_faults is an array split into four regions:
1332          * faults_memory, faults_cpu, faults_memory_buffer, faults_cpu_buffer
1333          * in this precise order.
1334          *
1335          * faults_memory: Exponential decaying average of faults on a per-node
1336          * basis. Scheduling placement decisions are made based on these
1337          * counts. The values remain static for the duration of a PTE scan.
1338          * faults_cpu: Track the nodes the process was running on when a NUMA
1339          * hinting fault was incurred.
1340          * faults_memory_buffer and faults_cpu_buffer: Record faults per node
1341          * during the current scan window. When the scan completes, the counts
1342          * in faults_memory and faults_cpu decay and these values are copied.
1343          */
1344         unsigned long                   *numa_faults;
1345         unsigned long                   total_numa_faults;
1346
1347         /*
1348          * numa_faults_locality tracks if faults recorded during the last
1349          * scan window were remote/local or failed to migrate. The task scan
1350          * period is adapted based on the locality of the faults with different
1351          * weights depending on whether they were shared or private faults
1352          */
1353         unsigned long                   numa_faults_locality[3];
1354
1355         unsigned long                   numa_pages_migrated;
1356 #endif /* CONFIG_NUMA_BALANCING */
1357
1358 #ifdef CONFIG_RSEQ
1359         struct rseq __user *rseq;
1360         u32 rseq_len;
1361         u32 rseq_sig;
1362         /*
1363          * RmW on rseq_event_mask must be performed atomically
1364          * with respect to preemption.
1365          */
1366         unsigned long rseq_event_mask;
1367 #endif
1368
1369 #ifdef CONFIG_SCHED_MM_CID
1370         int                             mm_cid;         /* Current cid in mm */
1371         int                             last_mm_cid;    /* Most recent cid in mm */
1372         int                             migrate_from_cpu;
1373         int                             mm_cid_active;  /* Whether cid bitmap is active */
1374         struct callback_head            cid_work;
1375 #endif
1376
1377         struct tlbflush_unmap_batch     tlb_ubc;
1378
1379         /* Cache last used pipe for splice(): */
1380         struct pipe_inode_info          *splice_pipe;
1381
1382         struct page_frag                task_frag;
1383
1384 #ifdef CONFIG_TASK_DELAY_ACCT
1385         struct task_delay_info          *delays;
1386 #endif
1387
1388 #ifdef CONFIG_FAULT_INJECTION
1389         int                             make_it_fail;
1390         unsigned int                    fail_nth;
1391 #endif
1392         /*
1393          * When (nr_dirtied >= nr_dirtied_pause), it's time to call
1394          * balance_dirty_pages() for a dirty throttling pause:
1395          */
1396         int                             nr_dirtied;
1397         int                             nr_dirtied_pause;
1398         /* Start of a write-and-pause period: */
1399         unsigned long                   dirty_paused_when;
1400
1401 #ifdef CONFIG_LATENCYTOP
1402         int                             latency_record_count;
1403         struct latency_record           latency_record[LT_SAVECOUNT];
1404 #endif
1405         /*
1406          * Time slack values; these are used to round up poll() and
1407          * select() etc timeout values. These are in nanoseconds.
1408          */
1409         u64                             timer_slack_ns;
1410         u64                             default_timer_slack_ns;
1411
1412 #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
1413         unsigned int                    kasan_depth;
1414 #endif
1415
1416 #ifdef CONFIG_KCSAN
1417         struct kcsan_ctx                kcsan_ctx;
1418 #ifdef CONFIG_TRACE_IRQFLAGS
1419         struct irqtrace_events          kcsan_save_irqtrace;
1420 #endif
1421 #ifdef CONFIG_KCSAN_WEAK_MEMORY
1422         int                             kcsan_stack_depth;
1423 #endif
1424 #endif
1425
1426 #ifdef CONFIG_KMSAN
1427         struct kmsan_ctx                kmsan_ctx;
1428 #endif
1429
1430 #if IS_ENABLED(CONFIG_KUNIT)
1431         struct kunit                    *kunit_test;
1432 #endif
1433
1434 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
1435         /* Index of current stored address in ret_stack: */
1436         int                             curr_ret_stack;
1437         int                             curr_ret_depth;
1438
1439         /* Stack of return addresses for return function tracing: */
1440         unsigned long                   *ret_stack;
1441
1442         /* Timestamp for last schedule: */
1443         unsigned long long              ftrace_timestamp;
1444
1445         /*
1446          * Number of functions that haven't been traced
1447          * because of depth overrun:
1448          */
1449         atomic_t                        trace_overrun;
1450
1451         /* Pause tracing: */
1452         atomic_t                        tracing_graph_pause;
1453 #endif
1454
1455 #ifdef CONFIG_TRACING
1456         /* Bitmask and counter of trace recursion: */
1457         unsigned long                   trace_recursion;
1458 #endif /* CONFIG_TRACING */
1459
1460 #ifdef CONFIG_KCOV
1461         /* See kernel/kcov.c for more details. */
1462
1463         /* Coverage collection mode enabled for this task (0 if disabled): */
1464         unsigned int                    kcov_mode;
1465
1466         /* Size of the kcov_area: */
1467         unsigned int                    kcov_size;
1468
1469         /* Buffer for coverage collection: */
1470         void                            *kcov_area;
1471
1472         /* KCOV descriptor wired with this task or NULL: */
1473         struct kcov                     *kcov;
1474
1475         /* KCOV common handle for remote coverage collection: */
1476         u64                             kcov_handle;
1477
1478         /* KCOV sequence number: */
1479         int                             kcov_sequence;
1480
1481         /* Collect coverage from softirq context: */
1482         unsigned int                    kcov_softirq;
1483 #endif
1484
1485 #ifdef CONFIG_MEMCG_V1
1486         struct mem_cgroup               *memcg_in_oom;
1487 #endif
1488
1489 #ifdef CONFIG_MEMCG
1490         /* Number of pages to reclaim on returning to userland: */
1491         unsigned int                    memcg_nr_pages_over_high;
1492
1493         /* Used by memcontrol for targeted memcg charge: */
1494         struct mem_cgroup               *active_memcg;
1495
1496         /* Cache for current->cgroups->memcg->objcg lookups: */
1497         struct obj_cgroup               *objcg;
1498 #endif
1499
1500 #ifdef CONFIG_BLK_CGROUP
1501         struct gendisk                  *throttle_disk;
1502 #endif
1503
1504 #ifdef CONFIG_UPROBES
1505         struct uprobe_task              *utask;
1506 #endif
1507 #if defined(CONFIG_BCACHE) || defined(CONFIG_BCACHE_MODULE)
1508         unsigned int                    sequential_io;
1509         unsigned int                    sequential_io_avg;
1510 #endif
1511         struct kmap_ctrl                kmap_ctrl;
1512 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
1513         unsigned long                   task_state_change;
1514 # ifdef CONFIG_PREEMPT_RT
1515         unsigned long                   saved_state_change;
1516 # endif
1517 #endif
1518         struct rcu_head                 rcu;
1519         refcount_t                      rcu_users;
1520         int                             pagefault_disabled;
1521 #ifdef CONFIG_MMU
1522         struct task_struct              *oom_reaper_list;
1523         struct timer_list               oom_reaper_timer;
1524 #endif
1525 #ifdef CONFIG_VMAP_STACK
1526         struct vm_struct                *stack_vm_area;
1527 #endif
1528 #ifdef CONFIG_THREAD_INFO_IN_TASK
1529         /* A live task holds one reference: */
1530         refcount_t                      stack_refcount;
1531 #endif
1532 #ifdef CONFIG_LIVEPATCH
1533         int patch_state;
1534 #endif
1535 #ifdef CONFIG_SECURITY
1536         /* Used by LSM modules for access restriction: */
1537         void                            *security;
1538 #endif
1539 #ifdef CONFIG_BPF_SYSCALL
1540         /* Used by BPF task local storage */
1541         struct bpf_local_storage __rcu  *bpf_storage;
1542         /* Used for BPF run context */
1543         struct bpf_run_ctx              *bpf_ctx;
1544 #endif
1545         /* Used by BPF for per-TASK xdp storage */
1546         struct bpf_net_context          *bpf_net_context;
1547
1548 #ifdef CONFIG_GCC_PLUGIN_STACKLEAK
1549         unsigned long                   lowest_stack;
1550         unsigned long                   prev_lowest_stack;
1551 #endif
1552
1553 #ifdef CONFIG_X86_MCE
1554         void __user                     *mce_vaddr;
1555         __u64                           mce_kflags;
1556         u64                             mce_addr;
1557         __u64                           mce_ripv : 1,
1558                                         mce_whole_page : 1,
1559                                         __mce_reserved : 62;
1560         struct callback_head            mce_kill_me;
1561         int                             mce_count;
1562 #endif
1563
1564 #ifdef CONFIG_KRETPROBES
1565         struct llist_head               kretprobe_instances;
1566 #endif
1567 #ifdef CONFIG_RETHOOK
1568         struct llist_head               rethooks;
1569 #endif
1570
1571 #ifdef CONFIG_ARCH_HAS_PARANOID_L1D_FLUSH
1572         /*
1573          * If L1D flush is supported on mm context switch
1574          * then we use this callback head to queue kill work
1575          * to kill tasks that are not running on SMT disabled
1576          * cores
1577          */
1578         struct callback_head            l1d_flush_kill;
1579 #endif
1580
1581 #ifdef CONFIG_RV
1582         /*
1583          * Per-task RV monitor. Nowadays fixed in RV_PER_TASK_MONITORS.
1584          * If we find justification for more monitors, we can think
1585          * about adding more or developing a dynamic method. So far,
1586          * none of these are justified.
1587          */
1588         union rv_task_monitor           rv[RV_PER_TASK_MONITORS];
1589 #endif
1590
1591 #ifdef CONFIG_USER_EVENTS
1592         struct user_event_mm            *user_event_mm;
1593 #endif
1594
1595         /*
1596          * New fields for task_struct should be added above here, so that
1597          * they are included in the randomized portion of task_struct.
1598          */
1599         randomized_struct_fields_end
1600
1601         /* CPU-specific state of this task: */
1602         struct thread_struct            thread;
1603
1604         /*
1605          * WARNING: on x86, 'thread_struct' contains a variable-sized
1606          * structure.  It *MUST* be at the end of 'task_struct'.
1607          *
1608          * Do not put anything below here!
1609          */
1610 };
1611
1612 #define TASK_REPORT_IDLE        (TASK_REPORT + 1)
1613 #define TASK_REPORT_MAX         (TASK_REPORT_IDLE << 1)
1614
1615 static inline unsigned int __task_state_index(unsigned int tsk_state,
1616                                               unsigned int tsk_exit_state)
1617 {
1618         unsigned int state = (tsk_state | tsk_exit_state) & TASK_REPORT;
1619
1620         BUILD_BUG_ON_NOT_POWER_OF_2(TASK_REPORT_MAX);
1621
1622         if ((tsk_state & TASK_IDLE) == TASK_IDLE)
1623                 state = TASK_REPORT_IDLE;
1624
1625         /*
1626          * We're lying here, but rather than expose a completely new task state
1627          * to userspace, we can make this appear as if the task has gone through
1628          * a regular rt_mutex_lock() call.
1629          */
1630         if (tsk_state & TASK_RTLOCK_WAIT)
1631                 state = TASK_UNINTERRUPTIBLE;
1632
1633         return fls(state);
1634 }
1635
1636 static inline unsigned int task_state_index(struct task_struct *tsk)
1637 {
1638         return __task_state_index(READ_ONCE(tsk->__state), tsk->exit_state);
1639 }
1640
1641 static inline char task_index_to_char(unsigned int state)
1642 {
1643         static const char state_char[] = "RSDTtXZPI";
1644
1645         BUILD_BUG_ON(TASK_REPORT_MAX * 2 != 1 << (sizeof(state_char) - 1));
1646
1647         return state_char[state];
1648 }
1649
1650 static inline char task_state_to_char(struct task_struct *tsk)
1651 {
1652         return task_index_to_char(task_state_index(tsk));
1653 }
1654
1655 extern struct pid *cad_pid;
1656
1657 /*
1658  * Per process flags
1659  */
1660 #define PF_VCPU                 0x00000001      /* I'm a virtual CPU */
1661 #define PF_IDLE                 0x00000002      /* I am an IDLE thread */
1662 #define PF_EXITING              0x00000004      /* Getting shut down */
1663 #define PF_POSTCOREDUMP         0x00000008      /* Coredumps should ignore this task */
1664 #define PF_IO_WORKER            0x00000010      /* Task is an IO worker */
1665 #define PF_WQ_WORKER            0x00000020      /* I'm a workqueue worker */
1666 #define PF_FORKNOEXEC           0x00000040      /* Forked but didn't exec */
1667 #define PF_MCE_PROCESS          0x00000080      /* Process policy on mce errors */
1668 #define PF_SUPERPRIV            0x00000100      /* Used super-user privileges */
1669 #define PF_DUMPCORE             0x00000200      /* Dumped core */
1670 #define PF_SIGNALED             0x00000400      /* Killed by a signal */
1671 #define PF_MEMALLOC             0x00000800      /* Allocating memory to free memory. See memalloc_noreclaim_save() */
1672 #define PF_NPROC_EXCEEDED       0x00001000      /* set_user() noticed that RLIMIT_NPROC was exceeded */
1673 #define PF_USED_MATH            0x00002000      /* If unset the fpu must be initialized before use */
1674 #define PF_USER_WORKER          0x00004000      /* Kernel thread cloned from userspace thread */
1675 #define PF_NOFREEZE             0x00008000      /* This thread should not be frozen */
1676 #define PF__HOLE__00010000      0x00010000
1677 #define PF_KSWAPD               0x00020000      /* I am kswapd */
1678 #define PF_MEMALLOC_NOFS        0x00040000      /* All allocations inherit GFP_NOFS. See memalloc_nfs_save() */
1679 #define PF_MEMALLOC_NOIO        0x00080000      /* All allocations inherit GFP_NOIO. See memalloc_noio_save() */
1680 #define PF_LOCAL_THROTTLE       0x00100000      /* Throttle writes only against the bdi I write to,
1681                                                  * I am cleaning dirty pages from some other bdi. */
1682 #define PF_KTHREAD              0x00200000      /* I am a kernel thread */
1683 #define PF_RANDOMIZE            0x00400000      /* Randomize virtual address space */
1684 #define PF_MEMALLOC_NORECLAIM   0x00800000      /* All allocation requests will clear __GFP_DIRECT_RECLAIM */
1685 #define PF_MEMALLOC_NOWARN      0x01000000      /* All allocation requests will inherit __GFP_NOWARN */
1686 #define PF__HOLE__02000000      0x02000000
1687 #define PF_NO_SETAFFINITY       0x04000000      /* Userland is not allowed to meddle with cpus_mask */
1688 #define PF_MCE_EARLY            0x08000000      /* Early kill for mce process policy */
1689 #define PF_MEMALLOC_PIN         0x10000000      /* Allocations constrained to zones which allow long term pinning.
1690                                                  * See memalloc_pin_save() */
1691 #define PF_BLOCK_TS             0x20000000      /* plug has ts that needs updating */
1692 #define PF__HOLE__40000000      0x40000000
1693 #define PF_SUSPEND_TASK         0x80000000      /* This thread called freeze_processes() and should not be frozen */
1694
1695 /*
1696  * Only the _current_ task can read/write to tsk->flags, but other
1697  * tasks can access tsk->flags in readonly mode for example
1698  * with tsk_used_math (like during threaded core dumping).
1699  * There is however an exception to this rule during ptrace
1700  * or during fork: the ptracer task is allowed to write to the
1701  * child->flags of its traced child (same goes for fork, the parent
1702  * can write to the child->flags), because we're guaranteed the
1703  * child is not running and in turn not changing child->flags
1704  * at the same time the parent does it.
1705  */
1706 #define clear_stopped_child_used_math(child)    do { (child)->flags &= ~PF_USED_MATH; } while (0)
1707 #define set_stopped_child_used_math(child)      do { (child)->flags |= PF_USED_MATH; } while (0)
1708 #define clear_used_math()                       clear_stopped_child_used_math(current)
1709 #define set_used_math()                         set_stopped_child_used_math(current)
1710
1711 #define conditional_stopped_child_used_math(condition, child) \
1712         do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= (condition) ? PF_USED_MATH : 0; } while (0)
1713
1714 #define conditional_used_math(condition)        conditional_stopped_child_used_math(condition, current)
1715
1716 #define copy_to_stopped_child_used_math(child) \
1717         do { (child)->flags &= ~PF_USED_MATH, (child)->flags |= current->flags & PF_USED_MATH; } while (0)
1718
1719 /* NOTE: this will return 0 or PF_USED_MATH, it will never return 1 */
1720 #define tsk_used_math(p)                        ((p)->flags & PF_USED_MATH)
1721 #define used_math()                             tsk_used_math(current)
1722
1723 static __always_inline bool is_percpu_thread(void)
1724 {
1725 #ifdef CONFIG_SMP
1726         return (current->flags & PF_NO_SETAFFINITY) &&
1727                 (current->nr_cpus_allowed  == 1);
1728 #else
1729         return true;
1730 #endif
1731 }
1732
1733 /* Per-process atomic flags. */
1734 #define PFA_NO_NEW_PRIVS                0       /* May not gain new privileges. */
1735 #define PFA_SPREAD_PAGE                 1       /* Spread page cache over cpuset */
1736 #define PFA_SPREAD_SLAB                 2       /* Spread some slab caches over cpuset */
1737 #define PFA_SPEC_SSB_DISABLE            3       /* Speculative Store Bypass disabled */
1738 #define PFA_SPEC_SSB_FORCE_DISABLE      4       /* Speculative Store Bypass force disabled*/
1739 #define PFA_SPEC_IB_DISABLE             5       /* Indirect branch speculation restricted */
1740 #define PFA_SPEC_IB_FORCE_DISABLE       6       /* Indirect branch speculation permanently restricted */
1741 #define PFA_SPEC_SSB_NOEXEC             7       /* Speculative Store Bypass clear on execve() */
1742
1743 #define TASK_PFA_TEST(name, func)                                       \
1744         static inline bool task_##func(struct task_struct *p)           \
1745         { return test_bit(PFA_##name, &p->atomic_flags); }
1746
1747 #define TASK_PFA_SET(name, func)                                        \
1748         static inline void task_set_##func(struct task_struct *p)       \
1749         { set_bit(PFA_##name, &p->atomic_flags); }
1750
1751 #define TASK_PFA_CLEAR(name, func)                                      \
1752         static inline void task_clear_##func(struct task_struct *p)     \
1753         { clear_bit(PFA_##name, &p->atomic_flags); }
1754
1755 TASK_PFA_TEST(NO_NEW_PRIVS, no_new_privs)
1756 TASK_PFA_SET(NO_NEW_PRIVS, no_new_privs)
1757
1758 TASK_PFA_TEST(SPREAD_PAGE, spread_page)
1759 TASK_PFA_SET(SPREAD_PAGE, spread_page)
1760 TASK_PFA_CLEAR(SPREAD_PAGE, spread_page)
1761
1762 TASK_PFA_TEST(SPREAD_SLAB, spread_slab)
1763 TASK_PFA_SET(SPREAD_SLAB, spread_slab)
1764 TASK_PFA_CLEAR(SPREAD_SLAB, spread_slab)
1765
1766 TASK_PFA_TEST(SPEC_SSB_DISABLE, spec_ssb_disable)
1767 TASK_PFA_SET(SPEC_SSB_DISABLE, spec_ssb_disable)
1768 TASK_PFA_CLEAR(SPEC_SSB_DISABLE, spec_ssb_disable)
1769
1770 TASK_PFA_TEST(SPEC_SSB_NOEXEC, spec_ssb_noexec)
1771 TASK_PFA_SET(SPEC_SSB_NOEXEC, spec_ssb_noexec)
1772 TASK_PFA_CLEAR(SPEC_SSB_NOEXEC, spec_ssb_noexec)
1773
1774 TASK_PFA_TEST(SPEC_SSB_FORCE_DISABLE, spec_ssb_force_disable)
1775 TASK_PFA_SET(SPEC_SSB_FORCE_DISABLE, spec_ssb_force_disable)
1776
1777 TASK_PFA_TEST(SPEC_IB_DISABLE, spec_ib_disable)
1778 TASK_PFA_SET(SPEC_IB_DISABLE, spec_ib_disable)
1779 TASK_PFA_CLEAR(SPEC_IB_DISABLE, spec_ib_disable)
1780
1781 TASK_PFA_TEST(SPEC_IB_FORCE_DISABLE, spec_ib_force_disable)
1782 TASK_PFA_SET(SPEC_IB_FORCE_DISABLE, spec_ib_force_disable)
1783
1784 static inline void
1785 current_restore_flags(unsigned long orig_flags, unsigned long flags)
1786 {
1787         current->flags &= ~flags;
1788         current->flags |= orig_flags & flags;
1789 }
1790
1791 extern int cpuset_cpumask_can_shrink(const struct cpumask *cur, const struct cpumask *trial);
1792 extern int task_can_attach(struct task_struct *p);
1793 extern int dl_bw_alloc(int cpu, u64 dl_bw);
1794 extern void dl_bw_free(int cpu, u64 dl_bw);
1795 #ifdef CONFIG_SMP
1796
1797 /* do_set_cpus_allowed() - consider using set_cpus_allowed_ptr() instead */
1798 extern void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask);
1799
1800 /**
1801  * set_cpus_allowed_ptr - set CPU affinity mask of a task
1802  * @p: the task
1803  * @new_mask: CPU affinity mask
1804  *
1805  * Return: zero if successful, or a negative error code
1806  */
1807 extern int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask);
1808 extern int dup_user_cpus_ptr(struct task_struct *dst, struct task_struct *src, int node);
1809 extern void release_user_cpus_ptr(struct task_struct *p);
1810 extern int dl_task_check_affinity(struct task_struct *p, const struct cpumask *mask);
1811 extern void force_compatible_cpus_allowed_ptr(struct task_struct *p);
1812 extern void relax_compatible_cpus_allowed_ptr(struct task_struct *p);
1813 #else
1814 static inline void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
1815 {
1816 }
1817 static inline int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
1818 {
1819         /* Opencoded cpumask_test_cpu(0, new_mask) to avoid dependency on cpumask.h */
1820         if ((*cpumask_bits(new_mask) & 1) == 0)
1821                 return -EINVAL;
1822         return 0;
1823 }
1824 static inline int dup_user_cpus_ptr(struct task_struct *dst, struct task_struct *src, int node)
1825 {
1826         if (src->user_cpus_ptr)
1827                 return -EINVAL;
1828         return 0;
1829 }
1830 static inline void release_user_cpus_ptr(struct task_struct *p)
1831 {
1832         WARN_ON(p->user_cpus_ptr);
1833 }
1834
1835 static inline int dl_task_check_affinity(struct task_struct *p, const struct cpumask *mask)
1836 {
1837         return 0;
1838 }
1839 #endif
1840
1841 extern int yield_to(struct task_struct *p, bool preempt);
1842 extern void set_user_nice(struct task_struct *p, long nice);
1843 extern int task_prio(const struct task_struct *p);
1844
1845 /**
1846  * task_nice - return the nice value of a given task.
1847  * @p: the task in question.
1848  *
1849  * Return: The nice value [ -20 ... 0 ... 19 ].
1850  */
1851 static inline int task_nice(const struct task_struct *p)
1852 {
1853         return PRIO_TO_NICE((p)->static_prio);
1854 }
1855
1856 extern int can_nice(const struct task_struct *p, const int nice);
1857 extern int task_curr(const struct task_struct *p);
1858 extern int idle_cpu(int cpu);
1859 extern int available_idle_cpu(int cpu);
1860 extern int sched_setscheduler(struct task_struct *, int, const struct sched_param *);
1861 extern int sched_setscheduler_nocheck(struct task_struct *, int, const struct sched_param *);
1862 extern void sched_set_fifo(struct task_struct *p);
1863 extern void sched_set_fifo_low(struct task_struct *p);
1864 extern void sched_set_normal(struct task_struct *p, int nice);
1865 extern int sched_setattr(struct task_struct *, const struct sched_attr *);
1866 extern int sched_setattr_nocheck(struct task_struct *, const struct sched_attr *);
1867 extern struct task_struct *idle_task(int cpu);
1868
1869 /**
1870  * is_idle_task - is the specified task an idle task?
1871  * @p: the task in question.
1872  *
1873  * Return: 1 if @p is an idle task. 0 otherwise.
1874  */
1875 static __always_inline bool is_idle_task(const struct task_struct *p)
1876 {
1877         return !!(p->flags & PF_IDLE);
1878 }
1879
1880 extern struct task_struct *curr_task(int cpu);
1881 extern void ia64_set_curr_task(int cpu, struct task_struct *p);
1882
1883 void yield(void);
1884
1885 union thread_union {
1886         struct task_struct task;
1887 #ifndef CONFIG_THREAD_INFO_IN_TASK
1888         struct thread_info thread_info;
1889 #endif
1890         unsigned long stack[THREAD_SIZE/sizeof(long)];
1891 };
1892
1893 #ifndef CONFIG_THREAD_INFO_IN_TASK
1894 extern struct thread_info init_thread_info;
1895 #endif
1896
1897 extern unsigned long init_stack[THREAD_SIZE / sizeof(unsigned long)];
1898
1899 #ifdef CONFIG_THREAD_INFO_IN_TASK
1900 # define task_thread_info(task) (&(task)->thread_info)
1901 #elif !defined(__HAVE_THREAD_FUNCTIONS)
1902 # define task_thread_info(task) ((struct thread_info *)(task)->stack)
1903 #endif
1904
1905 /*
1906  * find a task by one of its numerical ids
1907  *
1908  * find_task_by_pid_ns():
1909  *      finds a task by its pid in the specified namespace
1910  * find_task_by_vpid():
1911  *      finds a task by its virtual pid
1912  *
1913  * see also find_vpid() etc in include/linux/pid.h
1914  */
1915
1916 extern struct task_struct *find_task_by_vpid(pid_t nr);
1917 extern struct task_struct *find_task_by_pid_ns(pid_t nr, struct pid_namespace *ns);
1918
1919 /*
1920  * find a task by its virtual pid and get the task struct
1921  */
1922 extern struct task_struct *find_get_task_by_vpid(pid_t nr);
1923
1924 extern int wake_up_state(struct task_struct *tsk, unsigned int state);
1925 extern int wake_up_process(struct task_struct *tsk);
1926 extern void wake_up_new_task(struct task_struct *tsk);
1927
1928 #ifdef CONFIG_SMP
1929 extern void kick_process(struct task_struct *tsk);
1930 #else
1931 static inline void kick_process(struct task_struct *tsk) { }
1932 #endif
1933
1934 extern void __set_task_comm(struct task_struct *tsk, const char *from, bool exec);
1935 #define set_task_comm(tsk, from) ({                     \
1936         BUILD_BUG_ON(sizeof(from) != TASK_COMM_LEN);    \
1937         __set_task_comm(tsk, from, false);              \
1938 })
1939
1940 extern char *__get_task_comm(char *to, size_t len, struct task_struct *tsk);
1941 #define get_task_comm(buf, tsk) ({                      \
1942         BUILD_BUG_ON(sizeof(buf) != TASK_COMM_LEN);     \
1943         __get_task_comm(buf, sizeof(buf), tsk);         \
1944 })
1945
1946 #ifdef CONFIG_SMP
1947 static __always_inline void scheduler_ipi(void)
1948 {
1949         /*
1950          * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting
1951          * TIF_NEED_RESCHED remotely (for the first time) will also send
1952          * this IPI.
1953          */
1954         preempt_fold_need_resched();
1955 }
1956 #else
1957 static inline void scheduler_ipi(void) { }
1958 #endif
1959
1960 extern unsigned long wait_task_inactive(struct task_struct *, unsigned int match_state);
1961
1962 /*
1963  * Set thread flags in other task's structures.
1964  * See asm/thread_info.h for TIF_xxxx flags available:
1965  */
1966 static inline void set_tsk_thread_flag(struct task_struct *tsk, int flag)
1967 {
1968         set_ti_thread_flag(task_thread_info(tsk), flag);
1969 }
1970
1971 static inline void clear_tsk_thread_flag(struct task_struct *tsk, int flag)
1972 {
1973         clear_ti_thread_flag(task_thread_info(tsk), flag);
1974 }
1975
1976 static inline void update_tsk_thread_flag(struct task_struct *tsk, int flag,
1977                                           bool value)
1978 {
1979         update_ti_thread_flag(task_thread_info(tsk), flag, value);
1980 }
1981
1982 static inline int test_and_set_tsk_thread_flag(struct task_struct *tsk, int flag)
1983 {
1984         return test_and_set_ti_thread_flag(task_thread_info(tsk), flag);
1985 }
1986
1987 static inline int test_and_clear_tsk_thread_flag(struct task_struct *tsk, int flag)
1988 {
1989         return test_and_clear_ti_thread_flag(task_thread_info(tsk), flag);
1990 }
1991
1992 static inline int test_tsk_thread_flag(struct task_struct *tsk, int flag)
1993 {
1994         return test_ti_thread_flag(task_thread_info(tsk), flag);
1995 }
1996
1997 static inline void set_tsk_need_resched(struct task_struct *tsk)
1998 {
1999         set_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
2000 }
2001
2002 static inline void clear_tsk_need_resched(struct task_struct *tsk)
2003 {
2004         clear_tsk_thread_flag(tsk,TIF_NEED_RESCHED);
2005 }
2006
2007 static inline int test_tsk_need_resched(struct task_struct *tsk)
2008 {
2009         return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED));
2010 }
2011
2012 /*
2013  * cond_resched() and cond_resched_lock(): latency reduction via
2014  * explicit rescheduling in places that are safe. The return
2015  * value indicates whether a reschedule was done in fact.
2016  * cond_resched_lock() will drop the spinlock before scheduling,
2017  */
2018 #if !defined(CONFIG_PREEMPTION) || defined(CONFIG_PREEMPT_DYNAMIC)
2019 extern int __cond_resched(void);
2020
2021 #if defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
2022
2023 void sched_dynamic_klp_enable(void);
2024 void sched_dynamic_klp_disable(void);
2025
2026 DECLARE_STATIC_CALL(cond_resched, __cond_resched);
2027
2028 static __always_inline int _cond_resched(void)
2029 {
2030         return static_call_mod(cond_resched)();
2031 }
2032
2033 #elif defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY)
2034
2035 extern int dynamic_cond_resched(void);
2036
2037 static __always_inline int _cond_resched(void)
2038 {
2039         return dynamic_cond_resched();
2040 }
2041
2042 #else /* !CONFIG_PREEMPTION */
2043
2044 static inline int _cond_resched(void)
2045 {
2046         klp_sched_try_switch();
2047         return __cond_resched();
2048 }
2049
2050 #endif /* PREEMPT_DYNAMIC && CONFIG_HAVE_PREEMPT_DYNAMIC_CALL */
2051
2052 #else /* CONFIG_PREEMPTION && !CONFIG_PREEMPT_DYNAMIC */
2053
2054 static inline int _cond_resched(void)
2055 {
2056         klp_sched_try_switch();
2057         return 0;
2058 }
2059
2060 #endif /* !CONFIG_PREEMPTION || CONFIG_PREEMPT_DYNAMIC */
2061
2062 #define cond_resched() ({                       \
2063         __might_resched(__FILE__, __LINE__, 0); \
2064         _cond_resched();                        \
2065 })
2066
2067 extern int __cond_resched_lock(spinlock_t *lock);
2068 extern int __cond_resched_rwlock_read(rwlock_t *lock);
2069 extern int __cond_resched_rwlock_write(rwlock_t *lock);
2070
2071 #define MIGHT_RESCHED_RCU_SHIFT         8
2072 #define MIGHT_RESCHED_PREEMPT_MASK      ((1U << MIGHT_RESCHED_RCU_SHIFT) - 1)
2073
2074 #ifndef CONFIG_PREEMPT_RT
2075 /*
2076  * Non RT kernels have an elevated preempt count due to the held lock,
2077  * but are not allowed to be inside a RCU read side critical section
2078  */
2079 # define PREEMPT_LOCK_RESCHED_OFFSETS   PREEMPT_LOCK_OFFSET
2080 #else
2081 /*
2082  * spin/rw_lock() on RT implies rcu_read_lock(). The might_sleep() check in
2083  * cond_resched*lock() has to take that into account because it checks for
2084  * preempt_count() and rcu_preempt_depth().
2085  */
2086 # define PREEMPT_LOCK_RESCHED_OFFSETS   \
2087         (PREEMPT_LOCK_OFFSET + (1U << MIGHT_RESCHED_RCU_SHIFT))
2088 #endif
2089
2090 #define cond_resched_lock(lock) ({                                              \
2091         __might_resched(__FILE__, __LINE__, PREEMPT_LOCK_RESCHED_OFFSETS);      \
2092         __cond_resched_lock(lock);                                              \
2093 })
2094
2095 #define cond_resched_rwlock_read(lock) ({                                       \
2096         __might_resched(__FILE__, __LINE__, PREEMPT_LOCK_RESCHED_OFFSETS);      \
2097         __cond_resched_rwlock_read(lock);                                       \
2098 })
2099
2100 #define cond_resched_rwlock_write(lock) ({                                      \
2101         __might_resched(__FILE__, __LINE__, PREEMPT_LOCK_RESCHED_OFFSETS);      \
2102         __cond_resched_rwlock_write(lock);                                      \
2103 })
2104
2105 static __always_inline bool need_resched(void)
2106 {
2107         return unlikely(tif_need_resched());
2108 }
2109
2110 /*
2111  * Wrappers for p->thread_info->cpu access. No-op on UP.
2112  */
2113 #ifdef CONFIG_SMP
2114
2115 static inline unsigned int task_cpu(const struct task_struct *p)
2116 {
2117         return READ_ONCE(task_thread_info(p)->cpu);
2118 }
2119
2120 extern void set_task_cpu(struct task_struct *p, unsigned int cpu);
2121
2122 #else
2123
2124 static inline unsigned int task_cpu(const struct task_struct *p)
2125 {
2126         return 0;
2127 }
2128
2129 static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
2130 {
2131 }
2132
2133 #endif /* CONFIG_SMP */
2134
2135 extern bool sched_task_on_rq(struct task_struct *p);
2136 extern unsigned long get_wchan(struct task_struct *p);
2137 extern struct task_struct *cpu_curr_snapshot(int cpu);
2138
2139 #include <linux/spinlock.h>
2140
2141 /*
2142  * In order to reduce various lock holder preemption latencies provide an
2143  * interface to see if a vCPU is currently running or not.
2144  *
2145  * This allows us to terminate optimistic spin loops and block, analogous to
2146  * the native optimistic spin heuristic of testing if the lock owner task is
2147  * running or not.
2148  */
2149 #ifndef vcpu_is_preempted
2150 static inline bool vcpu_is_preempted(int cpu)
2151 {
2152         return false;
2153 }
2154 #endif
2155
2156 extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
2157 extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
2158
2159 #ifndef TASK_SIZE_OF
2160 #define TASK_SIZE_OF(tsk)       TASK_SIZE
2161 #endif
2162
2163 #ifdef CONFIG_SMP
2164 static inline bool owner_on_cpu(struct task_struct *owner)
2165 {
2166         /*
2167          * As lock holder preemption issue, we both skip spinning if
2168          * task is not on cpu or its cpu is preempted
2169          */
2170         return READ_ONCE(owner->on_cpu) && !vcpu_is_preempted(task_cpu(owner));
2171 }
2172
2173 /* Returns effective CPU energy utilization, as seen by the scheduler */
2174 unsigned long sched_cpu_util(int cpu);
2175 #endif /* CONFIG_SMP */
2176
2177 #ifdef CONFIG_SCHED_CORE
2178 extern void sched_core_free(struct task_struct *tsk);
2179 extern void sched_core_fork(struct task_struct *p);
2180 extern int sched_core_share_pid(unsigned int cmd, pid_t pid, enum pid_type type,
2181                                 unsigned long uaddr);
2182 extern int sched_core_idle_cpu(int cpu);
2183 #else
2184 static inline void sched_core_free(struct task_struct *tsk) { }
2185 static inline void sched_core_fork(struct task_struct *p) { }
2186 static inline int sched_core_idle_cpu(int cpu) { return idle_cpu(cpu); }
2187 #endif
2188
2189 extern void sched_set_stop_task(int cpu, struct task_struct *stop);
2190
2191 #ifdef CONFIG_MEM_ALLOC_PROFILING
2192 static __always_inline struct alloc_tag *alloc_tag_save(struct alloc_tag *tag)
2193 {
2194         swap(current->alloc_tag, tag);
2195         return tag;
2196 }
2197
2198 static __always_inline void alloc_tag_restore(struct alloc_tag *tag, struct alloc_tag *old)
2199 {
2200 #ifdef CONFIG_MEM_ALLOC_PROFILING_DEBUG
2201         WARN(current->alloc_tag != tag, "current->alloc_tag was changed:\n");
2202 #endif
2203         current->alloc_tag = old;
2204 }
2205 #else
2206 #define alloc_tag_save(_tag)                    NULL
2207 #define alloc_tag_restore(_tag, _old)           do {} while (0)
2208 #endif
2209
2210 #endif
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