tools/testing/selftests/bpf/progs/preempt_lock.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <vmlinux.h>
   3 #include <bpf/bpf_helpers.h>
   4 #include <bpf/bpf_tracing.h>
   5 #include "bpf_misc.h"
   6 #include "bpf_experimental.h"
   7
   8 extern int bpf_copy_from_user_str(void *dst, u32 dst__sz, const void *unsafe_ptr__ign, u64 flags) __weak __ksym;
   9
  10 SEC("?tc")
  11 __failure __msg("BPF_EXIT instruction in main prog cannot be used inside bpf_preempt_disable-ed region")
  12 int preempt_lock_missing_1(struct __sk_buff *ctx)
  13 {
  14         bpf_preempt_disable();
  15         return 0;
  16 }
  17
  18 SEC("?tc")
  19 __failure __msg("BPF_EXIT instruction in main prog cannot be used inside bpf_preempt_disable-ed region")
  20 int preempt_lock_missing_2(struct __sk_buff *ctx)
  21 {
  22         bpf_preempt_disable();
  23         bpf_preempt_disable();
  24         return 0;
  25 }
  26
  27 SEC("?tc")
  28 __failure __msg("BPF_EXIT instruction in main prog cannot be used inside bpf_preempt_disable-ed region")
  29 int preempt_lock_missing_3(struct __sk_buff *ctx)
  30 {
  31         bpf_preempt_disable();
  32         bpf_preempt_disable();
  33         bpf_preempt_disable();
  34         return 0;
  35 }
  36
  37 SEC("?tc")
  38 __failure __msg("BPF_EXIT instruction in main prog cannot be used inside bpf_preempt_disable-ed region")
  39 int preempt_lock_missing_3_minus_2(struct __sk_buff *ctx)
  40 {
  41         bpf_preempt_disable();
  42         bpf_preempt_disable();
  43         bpf_preempt_disable();
  44         bpf_preempt_enable();
  45         bpf_preempt_enable();
  46         return 0;
  47 }
  48
  49 static __noinline void preempt_disable(void)
  50 {
  51         bpf_preempt_disable();
  52 }
  53
  54 static __noinline void preempt_enable(void)
  55 {
  56         bpf_preempt_enable();
  57 }
  58
  59 SEC("?tc")
  60 __failure __msg("BPF_EXIT instruction in main prog cannot be used inside bpf_preempt_disable-ed region")
  61 int preempt_lock_missing_1_subprog(struct __sk_buff *ctx)
  62 {
  63         preempt_disable();
  64         return 0;
  65 }
  66
  67 SEC("?tc")
  68 __failure __msg("BPF_EXIT instruction in main prog cannot be used inside bpf_preempt_disable-ed region")
  69 int preempt_lock_missing_2_subprog(struct __sk_buff *ctx)
  70 {
  71         preempt_disable();
  72         preempt_disable();
  73         return 0;
  74 }
  75
  76 SEC("?tc")
  77 __failure __msg("BPF_EXIT instruction in main prog cannot be used inside bpf_preempt_disable-ed region")
  78 int preempt_lock_missing_2_minus_1_subprog(struct __sk_buff *ctx)
  79 {
  80         preempt_disable();
  81         preempt_disable();
  82         preempt_enable();
  83         return 0;
  84 }
  85
  86 static __noinline void preempt_balance_subprog(void)
  87 {
  88         preempt_disable();
  89         preempt_enable();
  90 }
  91
  92 SEC("?tc")
  93 __success int preempt_balance(struct __sk_buff *ctx)
  94 {
  95         bpf_guard_preempt();
  96         return 0;
  97 }
  98
  99 SEC("?tc")
 100 __success int preempt_balance_subprog_test(struct __sk_buff *ctx)
 101 {
 102         preempt_balance_subprog();
 103         return 0;
 104 }
 105
 106 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
 107 __failure __msg("sleepable helper bpf_copy_from_user#")
 108 int preempt_sleepable_helper(void *ctx)
 109 {
 110         u32 data;
 111
 112         bpf_preempt_disable();
 113         bpf_copy_from_user(&data, sizeof(data), NULL);
 114         bpf_preempt_enable();
 115         return 0;
 116 }
 117
 118 SEC("?fentry.s/" SYS_PREFIX "sys_getpgid")
 119 __failure __msg("kernel func bpf_copy_from_user_str is sleepable within non-preemptible region")
 120 int preempt_sleepable_kfunc(void *ctx)
 121 {
 122         u32 data;
 123
 124         bpf_preempt_disable();
 125         bpf_copy_from_user_str(&data, sizeof(data), NULL, 0);
 126         bpf_preempt_enable();
 127         return 0;
 128 }
 129
 130 int __noinline preempt_global_subprog(void)
 131 {
 132         preempt_balance_subprog();
 133         return 0;
 134 }
 135
 136 SEC("?tc")
 137 __failure __msg("global function calls are not allowed with preemption disabled")
 138 int preempt_global_subprog_test(struct __sk_buff *ctx)
 139 {
 140         preempt_disable();
 141         preempt_global_subprog();
 142         preempt_enable();
 143         return 0;
 144 }
 145
 146 char _license[] SEC("license") = "GPL";