Steven Price [Tue, 4 Feb 2020 01:36:34 +0000 (17:36 -0800)]
arm64: mm: display non-present entries in ptdump
Previously the /sys/kernel/debug/kernel_page_tables file would only show
lines for entries present in the page tables. However it is useful to
also show non-present entries as this makes the size and level of the
holes more visible. This aligns the behaviour with x86 which also shows
holes.
Steven Price [Tue, 4 Feb 2020 01:36:11 +0000 (17:36 -0800)]
x86: mm+efi: convert ptdump_walk_pgd_level() to take a mm_struct
To enable x86 to use the generic walk_page_range() function, the callers
of ptdump_walk_pgd_level() need to pass an mm_struct rather than the raw
pgd_t pointer. Luckily since commit 7e904a91bf60 ("efi: Use efi_mm in x86
as well as ARM") we now have an mm_struct for EFI on x86.
Steven Price [Tue, 4 Feb 2020 01:36:07 +0000 (17:36 -0800)]
x86: mm: point to struct seq_file from struct pg_state
mm/dump_pagetables.c passes both struct seq_file and struct pg_state down
the chain of walk_*_level() functions to be passed to note_page().
Instead place the struct seq_file in struct pg_state and access it from
struct pg_state (which is private to this file) in note_page().
Steven Price [Tue, 4 Feb 2020 01:36:03 +0000 (17:36 -0800)]
mm: pagewalk: add 'depth' parameter to pte_hole
The pte_hole() callback is called at multiple levels of the page tables.
Code dumping the kernel page tables needs to know what at what depth the
missing entry is. Add this is an extra parameter to pte_hole(). When the
depth isn't know (e.g. processing a vma) then -1 is passed.
The depth that is reported is the actual level where the entry is missing
(ignoring any folding that is in place), i.e. any levels where
PTRS_PER_P?D is set to 1 are ignored.
Note that depth starts at 0 for a PGD so that PUD/PMD/PTE retain their
natural numbers as levels 2/3/4.
Steven Price [Tue, 4 Feb 2020 01:35:58 +0000 (17:35 -0800)]
mm: pagewalk: fix termination condition in walk_pte_range()
If walk_pte_range() is called with a 'end' argument that is beyond the
last page of memory (e.g. ~0UL) then the comparison between 'addr' and
'end' will always fail and the loop will be infinite. Instead change the
comparison to >= while accounting for overflow.
Steven Price [Tue, 4 Feb 2020 01:35:54 +0000 (17:35 -0800)]
mm: pagewalk: don't lock PTEs for walk_page_range_novma()
walk_page_range_novma() can be used to walk page tables or the kernel or
for firmware. These page tables may contain entries that are not backed
by a struct page and so it isn't (in general) possible to take the PTE
lock for the pte_entry() callback. So update walk_pte_range() to only
take the lock when no_vma==false by splitting out the inner loop to a
separate function and add a comment explaining the difference to
walk_page_range_novma().
Steven Price [Tue, 4 Feb 2020 01:35:50 +0000 (17:35 -0800)]
mm: pagewalk: allow walking without vma
Since 48684a65b4e3: "mm: pagewalk: fix misbehavior of walk_page_range for
vma(VM_PFNMAP)", page_table_walk() will report any kernel area as a hole,
because it lacks a vma.
This means each arch has re-implemented page table walking when needed,
for example in the per-arch ptdump walker.
Remove the requirement to have a vma in the generic code and add a new
function walk_page_range_novma() which ignores the VMAs and simply walks
the page tables.
Steven Price [Tue, 4 Feb 2020 01:35:45 +0000 (17:35 -0800)]
mm: pagewalk: add p4d_entry() and pgd_entry()
pgd_entry() and pud_entry() were removed by commit 0b1fbfe50006c410
("mm/pagewalk: remove pgd_entry() and pud_entry()") because there were no
users. We're about to add users so reintroduce them, along with
p4d_entry() as we now have 5 levels of tables.
Note that commit a00cc7d9dd93d66a ("mm, x86: add support for PUD-sized
transparent hugepages") already re-added pud_entry() but with different
semantics to the other callbacks. This commit reverts the semantics back
to match the other callbacks.
To support hmm.c which now uses the new semantics of pud_entry() a new
member ('action') of struct mm_walk is added which allows the callbacks to
either descend (ACTION_SUBTREE, the default), skip (ACTION_CONTINUE) or
repeat the callback (ACTION_AGAIN). hmm.c is then updated to call
pud_trans_huge_lock() itself and make use of the splitting/retry logic of
the core code.
After this change pud_entry() is called for all entries, not just
transparent huge pages.
Steven Price [Tue, 4 Feb 2020 01:35:41 +0000 (17:35 -0800)]
x86: mm: add p?d_leaf() definitions
walk_page_range() is going to be allowed to walk page tables other than
those of user space. For this it needs to know when it has reached a
'leaf' entry in the page tables. This information is provided by the
p?d_leaf() functions/macros.
For x86 we already have p?d_large() functions, so simply add macros to
provide the generic p?d_leaf() names for the generic code.
Steven Price [Tue, 4 Feb 2020 01:35:36 +0000 (17:35 -0800)]
sparc: mm: add p?d_leaf() definitions
walk_page_range() is going to be allowed to walk page tables other than
those of user space. For this it needs to know when it has reached a
'leaf' entry in the page tables. This information is provided by the
p?d_leaf() functions/macros.
For sparc 64 bit, pmd_large() and pud_large() are already provided, so add
macros to provide the p?d_leaf names required by the generic code.
Steven Price [Tue, 4 Feb 2020 01:35:32 +0000 (17:35 -0800)]
s390: mm: add p?d_leaf() definitions
walk_page_range() is going to be allowed to walk page tables other than
those of user space. For this it needs to know when it has reached a
'leaf' entry in the page tables. This information is provided by the
p?d_leaf() functions/macros.
For s390, pud_large() and pmd_large() are already implemented as static
inline functions. Add a macro to provide the p?d_leaf names for the
generic code to use.
Steven Price [Tue, 4 Feb 2020 01:35:28 +0000 (17:35 -0800)]
riscv: mm: add p?d_leaf() definitions
walk_page_range() is going to be allowed to walk page tables other than
those of user space. For this it needs to know when it has reached a
'leaf' entry in the page tables. This information is provided by the
p?d_leaf() functions/macros.
For riscv a page is a leaf page when it has a read, write or execute bit
set on it.
Steven Price [Tue, 4 Feb 2020 01:35:24 +0000 (17:35 -0800)]
powerpc: mm: add p?d_leaf() definitions
walk_page_range() is going to be allowed to walk page tables other than
those of user space. For this it needs to know when it has reached a
'leaf' entry in the page tables. This information is provided by the
p?d_leaf() functions/macros.
For powerpc p?d_is_leaf() functions already exist. Export them using the
new p?d_leaf() name.
Steven Price [Tue, 4 Feb 2020 01:35:19 +0000 (17:35 -0800)]
mips: mm: add p?d_leaf() definitions
walk_page_range() is going to be allowed to walk page tables other than
those of user space. For this it needs to know when it has reached a
'leaf' entry in the page tables. This information is provided by the
p?d_leaf() functions/macros.
If _PAGE_HUGE is defined we can simply look for it. When not defined we
can be confident that there are no leaf pages in existence and fall back
on the generic implementation (added in a later patch) which returns 0.
Steven Price [Tue, 4 Feb 2020 01:35:14 +0000 (17:35 -0800)]
arm64: mm: add p?d_leaf() definitions
walk_page_range() is going to be allowed to walk page tables other than
those of user space. For this it needs to know when it has reached a
'leaf' entry in the page tables. This information will be provided by the
p?d_leaf() functions/macros.
For arm64, we already have p?d_sect() macros which we can reuse for
p?d_leaf().
pud_sect() is defined as a dummy function when CONFIG_PGTABLE_LEVELS < 3
or CONFIG_ARM64_64K_PAGES is defined. However when the kernel is
configured this way then architecturally it isn't allowed to have a large
page at this level, and any code using these page walking macros is
implicitly relying on the page size/number of levels being the same as the
kernel. So it is safe to reuse this for p?d_leaf() as it is an
architectural restriction.
Steven Price [Tue, 4 Feb 2020 01:35:10 +0000 (17:35 -0800)]
arm: mm: add p?d_leaf() definitions
walk_page_range() is going to be allowed to walk page tables other than
those of user space. For this it needs to know when it has reached a
'leaf' entry in the page tables. This information is provided by the
p?d_leaf() functions/macros.
For arm pmd_large() already exists and does what we want. So simply
provide the generic pmd_leaf() name.
Steven Price [Tue, 4 Feb 2020 01:35:06 +0000 (17:35 -0800)]
arc: mm: add p?d_leaf() definitions
walk_page_range() is going to be allowed to walk page tables other than
those of user space. For this it needs to know when it has reached a
'leaf' entry in the page tables. This information will be provided by the
p?d_leaf() functions/macros.
For arc, we only have two levels, so only pmd_leaf() is needed.
Steven Price [Tue, 4 Feb 2020 01:35:01 +0000 (17:35 -0800)]
mm: add generic p?d_leaf() macros
Patch series "Generic page walk and ptdump", v17.
Many architectures current have a debugfs file for dumping the kernel page
tables. Currently each architecture has to implement custom functions for
this because the details of walking the page tables used by the kernel are
different between architectures.
This series extends the capabilities of walk_page_range() so that it can
deal with the page tables of the kernel (which have no VMAs and can
contain larger huge pages than exist for user space). A generic PTDUMP
implementation is the implemented making use of the new functionality of
walk_page_range() and finally arm64 and x86 are switch to using it,
removing the custom table walkers.
To enable a generic page table walker to walk the unusual mappings of the
kernel we need to implement a set of functions which let us know when the
walker has reached the leaf entry. After a suggestion from Will Deacon
I've chosen the name p?d_leaf() as this (hopefully) describes the purpose
(and is a new name so has no historic baggage). Some architectures have
p?d_large macros but this is easily confused with "large pages".
This series ends with a generic PTDUMP implemention for arm64 and x86.
Mostly this is a clean up and there should be very little functional
change. The exceptions are:
* arm64 PTDUMP debugfs now displays pages which aren't present (patch 22).
* arm64 has the ability to efficiently process KASAN pages (which
previously only x86 implemented). This means that the combination of
KASAN and DEBUG_WX is now useable.
This patch (of 23):
Exposing the pud/pgd levels of the page tables to walk_page_range() means
we may come across the exotic large mappings that come with large areas of
contiguous memory (such as the kernel's linear map).
For architectures that don't provide all p?d_leaf() macros, provide
generic do nothing default that are suitable where there cannot be leaf
pages at that level. Futher patches will add implementations for
individual architectures.
The name p?d_leaf() is chosen to minimize the confusion with existing uses
of "large" pages and "huge" pages which do not necessary mean that the
entry is a leaf (for example it may be a set of contiguous entries that
only take 1 TLB slot). For the purpose of walking the page tables we
don't need to know how it will be represented in the TLB, but we do need
to know for sure if it is a leaf of the tree.
Randy Dunlap [Tue, 4 Feb 2020 01:34:55 +0000 (17:34 -0800)]
pinctrl: fix pxa2xx.c build warnings
Add #include of <linux/pinctrl/machine.h> to fix build
warnings in pinctrl-pxa2xx.c. Fixes these warnings:
In file included from ../drivers/pinctrl/pxa/pinctrl-pxa2xx.c:24:0:
../drivers/pinctrl/pxa/../pinctrl-utils.h:36:8: warning: `enum pinctrl_map_type' declared inside parameter list [enabled by default]
enum pinctrl_map_type type);
^
../drivers/pinctrl/pxa/../pinctrl-utils.h:36:8: warning: its scope is only this definition or declaration, which is probably not what you want [enabled by default]
Andrew Morton [Tue, 4 Feb 2020 01:34:52 +0000 (17:34 -0800)]
drivers/block/null_blk_main.c: fix uninitialized var warnings
With gcc-7.2, many instances of
drivers/block/null_blk_main.c: In function ‘nullb_device_zone_nr_conv_store’:
drivers/block/null_blk_main.c:291:12: warning: ‘new_value’ may be used uninitialized in this function [-Wmaybe-uninitialized]
dev->NAME = new_value; \
^
drivers/block/null_blk_main.c:279:7: note: ‘new_value’ was declared here
TYPE new_value; \
^
Presumably notabug, so use uninitialized_var() to suppress them.
Lu Shuaibing [Tue, 4 Feb 2020 01:34:46 +0000 (17:34 -0800)]
ipc/msg.c: consolidate all xxxctl_down() functions
A use of uninitialized memory in msgctl_down() because msqid64 in
ksys_msgctl hasn't been initialized. The local | msqid64 | is created in
ksys_msgctl() and then passed into msgctl_down(). Along the way msqid64
is never initialized before msgctl_down() checks msqid64->msg_qbytes.
KUMSAN(KernelUninitializedMemorySantizer, a new error detection tool)
reports:
==================================================================
BUG: KUMSAN: use of uninitialized memory in msgctl_down+0x94/0x300
Read of size 8 at addr ffff88806bb97eb8 by task syz-executor707/2022
Manfred Spraul [Tue, 4 Feb 2020 01:34:39 +0000 (17:34 -0800)]
ipc/msg.c: update and document memory barriers
Transfer findings from ipc/mqueue.c:
- A control barrier was missing for the lockless receive case So in
theory, not yet initialized data may have been copied to user space -
obviously only for architectures where control barriers are not NOP.
- use smp_store_release(). In theory, the refount may have been
decreased to 0 already when wake_q_add() tries to get a reference.
Manfred Spraul [Tue, 4 Feb 2020 01:34:36 +0000 (17:34 -0800)]
ipc/mqueue.c: update/document memory barriers
Update and document memory barriers for mqueue.c:
- ewp->state is read without any locks, thus READ_ONCE is required.
- add smp_aquire__after_ctrl_dep() after the READ_ONCE, we need
acquire semantics if the value is STATE_READY.
- use wake_q_add_safe()
- document why __set_current_state() may be used:
Reading task->state cannot happen before the wake_q_add() call,
which happens while holding info->lock. Thus the spin_unlock()
is the RELEASE, and the spin_lock() is the ACQUIRE.
For completeness: there is also a 3 CPU scenario, if the to be woken
up task is already on another wake_q.
Then:
- CPU1: spin_unlock() of the task that goes to sleep is the RELEASE
- CPU2: the spin_lock() of the waker is the ACQUIRE
- CPU2: smp_mb__before_atomic inside wake_q_add() is the RELEASE
- CPU3: smp_mb__after_spinlock() inside try_to_wake_up() is the ACQUIRE
mm/memory_hotplug: poison memmap in remove_pfn_range_from_zone()
Let's poison the pages similar to when adding new memory in
sparse_add_section(). Also call remove_pfn_range_from_zone() from
memunmap_pages(), so we can poison the memmap from there as well.
mm/memmap_init: update variable name in memmap_init_zone
Patch series "mm/memory_hotplug: Shrink zones before removing memory", v6.
This series fixes the access of uninitialized memmaps when shrinking
zones/nodes and when removing memory. Also, it contains all fixes for
crashes that can be triggered when removing certain namespace using
memunmap_pages() - ZONE_DEVICE, reported by Aneesh.
We stop trying to shrink ZONE_DEVICE, as it's buggy, fixing it would be
more involved (we don't have SECTION_IS_ONLINE as an indicator), and
shrinking is only of limited use (set_zone_contiguous() cannot detect the
ZONE_DEVICE as contiguous).
We continue shrinking !ZONE_DEVICE zones, however, I reduced the amount of
code to a minimum. Shrinking is especially necessary to keep
zone->contiguous set where possible, especially, on memory unplug of DIMMs
at zone boundaries.
Zones are now properly shrunk when offlining memory blocks or when
onlining failed. This allows to properly shrink zones on memory unplug
even if the separate memory blocks of a DIMM were onlined to different
zones or re-onlined to a different zone after offlining.
Let's move it to the header and use the shorter variant from
mm/page_alloc.c (the original one will also check
"__highest_present_section_nr + 1", which is not necessary). While at
it, make the section_nr in next_pfn() const.
In next_pfn(), we now return section_nr_to_pfn(-1) instead of -1 once we
exceed __highest_present_section_nr, which doesn't make a difference in
the caller as it is big enough (>= all sane end_pfn).
mm/page_alloc: fix and rework pfn handling in memmap_init_zone()
Let's update the pfn manually whenever we continue the loop. This makes
the code easier to read but also less error prone (and we can directly fix
one issue).
When overlap_memmap_init() returns true, pfn is updated to
"memblock_region_memory_end_pfn(r)". So it already points at the *next*
pfn to process. Incrementing the pfn another time is wrong, we might
leave one uninitialized. I spotted this by inspecting the code, so I have
no idea if this is relevant in practise (with kernelcore=mirror).
mm/page_alloc.c: initialize memmap of unavailable memory directly
Let's make sure that all memory holes are actually marked PageReserved(),
that page_to_pfn() produces reliable results, and that these pages are not
detected as "mmap" pages due to the mapcount.
[root@localhost ~]# ./page-types -r -a 0x144000,
flags page-count MB symbolic-flags long-symbolic-flags
0x0000000000000800 16384 64 ___________M_______________________________ mmap
total 16384 64
After this change:
[root@localhost ~]# ./page-types -r -a 0x144000,
flags page-count MB symbolic-flags long-symbolic-flags
0x0000000100000000 16384 64 ___________________________r_______________ reserved
total 16384 64
IOW, especially the unavailable physical memory ("memory hole") in the
last section would not get properly marked PageReserved() and is indicated
to be "mmap" memory.
Drop the trace of that function from include/linux/mm.h - nobody else
needs it, and rename it accordingly.
Note: The fake zone/node might not be covered by the zone/node span. This
is not an urgent issue (for now, we had the same node/zone due to the
zeroing). We'll need a clean way to mark memory holes (e.g., using a page
type PageHole() if possible or a fake ZONE_INVALID) and eventually stop
marking these memory holes PageReserved().
fs/proc/page.c: allow inspection of last section and fix end detection
If max_pfn does not fall onto a section boundary, it is possible to
inspect PFNs up to max_pfn, and PFNs above max_pfn, however, max_pfn
itself can't be inspected. We can have a valid (and online) memmap at and
above max_pfn if max_pfn is not aligned to a section boundary. The whole
early section has a memmap and is marked online. Being able to inspect
the state of these PFNs is valuable for debugging, especially because
max_pfn can change on memory hotplug and expose these memmaps.
Also, querying page flags via "./page-types -r -a 0x144001,"
(tools/vm/page-types.c) inside a x86-64 guest with 4160MB under QEMU
results in an (almost) endless loop in user space, because the end is not
detected properly when starting after max_pfn.
Instead, let's allow to inspect all pages in the highest section and
return 0 directly if we try to access pages above that section.
While at it, check the count before adjusting it, to avoid masking user
errors.
mm/page_alloc.c: fix uninitialized memmaps on a partially populated last section
Patch series "mm: fix max_pfn not falling on section boundary", v2.
Playing with different memory sizes for a x86-64 guest, I discovered that
some memmaps (highest section if max_mem does not fall on the section
boundary) are marked as being valid and online, but contain garbage. We
have to properly initialize these memmaps.
Looking at /proc/kpageflags and friends, I found some more issues,
partially related to this.
This patch (of 3):
If max_pfn is not aligned to a section boundary, we can easily run into
BUGs. This can e.g., be triggered on x86-64 under QEMU by specifying a
memory size that is not a multiple of 128MB (e.g., 4097MB, but also
4160MB). I was told that on real HW, we can easily have this scenario
(esp., one of the main reasons sub-section hotadd of devmem was added).
The issue is, that we have a valid memmap (pfn_valid()) for the whole
section, and the whole section will be marked "online".
pfn_to_online_page() will succeed, but the memmap contains garbage.
E.g., doing a "./page-types -r -a 0x144001" when QEMU was started with "-m
4160M" - (see tools/vm/page-types.c):
This patch fixes that by at least zero-ing out that memmap (so e.g.,
page_to_pfn() will not crash). Commit 907ec5fca3dc ("mm: zero remaining
unavailable struct pages") tried to fix a similar issue, but forgot to
consider this special case.
After this patch, there are still problems to solve. E.g., not all of
these pages falling into a memory hole will actually get initialized later
and set PageReserved - they are only zeroed out - but at least the
immediate crashes are gone. A follow-up patch will take care of this.
Jens Axboe [Mon, 3 Feb 2020 17:33:42 +0000 (10:33 -0700)]
aio: prevent potential eventfd recursion on poll
If we have nested or circular eventfd wakeups, then we can deadlock if
we run them inline from our poll waitqueue wakeup handler. It's also
possible to have very long chains of notifications, to the extent where
we could risk blowing the stack.
Check the eventfd recursion count before calling eventfd_signal(). If
it's non-zero, then punt the signaling to async context. This is always
safe, as it takes us out-of-line in terms of stack and locking context.
Jens Axboe [Sat, 1 Feb 2020 16:22:49 +0000 (09:22 -0700)]
io_uring: punt even fadvise() WILLNEED to async context
Andres correctly points out that read-ahead can block, if it needs to
read in meta data (or even just through the page cache page allocations).
Play it safe for now and just ensure WILLNEED is also punted to async
context.
While in there, allow the file settings hints from non-blocking
context. They don't need to start/do IO, and we can safely do them
inline.
Jens Axboe [Sat, 1 Feb 2020 00:16:48 +0000 (17:16 -0700)]
io_uring: fix sporadic double CQE entry for close
We punt close to async for the final fput(), but we log the completion
even before that even in that case. We rely on the request not having
a files table assigned to detect what the final async close should do.
However, if we punt the async queue to __io_queue_sqe(), we'll get
->files assigned and this makes io_close_finish() think it should both
close the filp again (which does no harm) AND log a new CQE event for
this request. This causes duplicate CQEs.
Queue the request up for async manually so we don't grab files
needlessly and trigger this condition.
If we have a read/write that is deferred, we already setup the async IO
context for that request, and mapped it. When we later try and execute
the request and we get -EAGAIN, we don't want to attempt to re-map it.
If we do, we end up with garbage in the iovec, which typically leads
to an -EFAULT or -EINVAL completion.
Jens Axboe [Sun, 2 Feb 2020 04:30:11 +0000 (21:30 -0700)]
io_uring: prevent potential eventfd recursion on poll
If we have nested or circular eventfd wakeups, then we can deadlock if
we run them inline from our poll waitqueue wakeup handler. It's also
possible to have very long chains of notifications, to the extent where
we could risk blowing the stack.
Check the eventfd recursion count before calling eventfd_signal(). If
it's non-zero, then punt the signaling to async context. This is always
safe, as it takes us out-of-line in terms of stack and locking context.
Jens Axboe [Sun, 2 Feb 2020 15:23:03 +0000 (08:23 -0700)]
eventfd: track eventfd_signal() recursion depth
eventfd use cases from aio and io_uring can deadlock due to circular
or resursive calling, when eventfd_signal() tries to grab the waitqueue
lock. On top of that, it's also possible to construct notification
chains that are deep enough that we could blow the stack.
Add a percpu counter that tracks the percpu recursion depth, warn if we
exceed it. The counter is also exposed so that users of eventfd_signal()
can do the right thing if it's non-zero in the context where it is
called.
=====================
netdevsim: fix several bugs in netdevsim module
This patchset fixes several bugs in netdevsim module.
1. The first patch fixes using uninitialized resources
This patch fixes two similar problems, which is to use uninitialized
resources.
a) In the current code, {new/del}_device_store() use resource,
they are initialized by __init().
But, these functions could be called before __init() is finished.
So, accessing uninitialized data could occur and it eventually makes panic.
b) In the current code, {new/del}_port_store() uses resource,
they are initialized by new_device_store().
But thes functions could be called before new_device_store() is finished.
2. The second patch fixes another race condition.
The main problem is a race condition in {new/del}_port() and devlink reload
function.
These functions would allocate and remove resources. So these functions
should not be executed concurrently.
3. The third patch fixes a panic in nsim_dev_take_snapshot_write().
nsim_dev_take_snapshot_write() uses nsim_dev and nsim_dev->dummy_region.
But these data could be removed by both reload routine and
del_device_store(). And these functions could be executed concurrently.
4. The fourth patch fixes stack-out-of-bound in nsim_dev_debugfs_init().
nsim_dev_debugfs_init() provides only 16bytes for name pointer.
But, there are some case the name length is over 16bytes.
So, stack-out-of-bound occurs.
5. The fifth patch uses IS_ERR instead of IS_ERR_OR_NULL.
debugfs_create_{dir/file} doesn't return NULL.
So, IS_ERR() is more correct.
6. The sixth patch avoids kmalloc warning.
When too large memory allocation is requested by user-space, kmalloc
internally prints warning message.
That warning message is not necessary.
In order to avoid that, it adds __GFP_NOWARN.
7. The last patch removes an unused sdev.c file
Change log:
v2 -> v3:
- Use smp_load_acquire() and smp_store_release() for flag variables.
- Change variable names.
- Fix deadlock in second patch.
- Update lock variable comment.
- Add new patch for fixing panic in snapshot_write().
- Include Reviewed-by tags.
- Update some log messages and comment.
v1 -> v2:
- Splits a fixing race condition patch into two patches.
- Fix incorrect Fixes tags.
- Update comments
- Fix use-after-free
- Add a new patch, which removes an unused sdev.c file.
- Remove a patch, which tries to avoid debugfs warning.
=====================
Taehee Yoo [Sat, 1 Feb 2020 16:43:39 +0000 (16:43 +0000)]
netdevsim: use __GFP_NOWARN to avoid memalloc warning
vfnum buffer size and binary_len buffer size is received by user-space.
So, this buffer size could be too large. If so, kmalloc will internally
print a warning message.
This warning message is actually not necessary for the netdevsim module.
So, this patch adds __GFP_NOWARN.
Taehee Yoo [Sat, 1 Feb 2020 16:43:22 +0000 (16:43 +0000)]
netdevsim: fix stack-out-of-bounds in nsim_dev_debugfs_init()
When netdevsim dev is being created, a debugfs directory is created.
The variable "dev_ddir_name" is 16bytes device name pointer and device
name is "netdevsim<dev id>".
The maximum dev id length is 10.
So, 16bytes for device name isn't enough.
Test commands:
modprobe netdevsim
echo "1000000000 0" > /sys/bus/netdevsim/new_device
Taehee Yoo [Sat, 1 Feb 2020 16:43:13 +0000 (16:43 +0000)]
netdevsim: fix panic in nsim_dev_take_snapshot_write()
nsim_dev_take_snapshot_write() uses nsim_dev and nsim_dev->dummy_region.
So, during this function, these data shouldn't be removed.
But there is no protecting stuff in this function.
There are two similar cases.
1. reload case
reload could be called during nsim_dev_take_snapshot_write().
When reload is being executed, nsim_dev_reload_down() is called and it
calls nsim_dev_reload_destroy(). nsim_dev_reload_destroy() calls
devlink_region_destroy() to destroy nsim_dev->dummy_region.
So, during nsim_dev_take_snapshot_write(), nsim_dev->dummy_region()
would be removed.
At this point, snapshot_write() would access freed pointer.
In order to fix this case, take_snapshot file will be removed before
devlink_region_destroy().
The take_snapshot file will be re-created by ->reload_up().
2. del_device_store case
del_device_store() also could call nsim_dev_reload_destroy()
during nsim_dev_take_snapshot_write(). If so, panic would occur.
This problem is actually the same problem with the first case.
So, this problem will be fixed by the first case's solution.
Test commands:
modprobe netdevsim
while :
do
echo 1 > /sys/bus/netdevsim/new_device &
echo 1 > /sys/bus/netdevsim/del_device &
devlink dev reload netdevsim/netdevsim1 &
echo 1 > /sys/kernel/debug/netdevsim/netdevsim1/take_snapshot &
done
Fixes: 4418f862d675 ("netdevsim: implement support for devlink region and snapshots") Signed-off-by: Taehee Yoo <[email protected]> Signed-off-by: Jakub Kicinski <[email protected]>
Taehee Yoo [Sat, 1 Feb 2020 16:43:04 +0000 (16:43 +0000)]
netdevsim: disable devlink reload when resources are being used
devlink reload destroys resources and allocates resources again.
So, when devices and ports resources are being used, devlink reload
function should not be executed. In order to avoid this race, a new
lock is added and new_port() and del_port() call devlink_reload_disable()
and devlink_reload_enable().
Before Thread1's devlink_reload_enable(), the devlink is already allowed
to execute reload because Thread0 allows it. devlink reload disable/enable
variable type is bool. So the above case would exist.
So, disable/enable should be executed atomically.
In order to do that, a new lock is used.
Test commands:
modprobe netdevsim
echo 1 > /sys/bus/netdevsim/new_device
while :
do
echo 1 > /sys/devices/netdevsim1/new_port &
echo 1 > /sys/devices/netdevsim1/del_port &
devlink dev reload netdevsim/netdevsim1 &
done
Taehee Yoo [Sat, 1 Feb 2020 16:42:54 +0000 (16:42 +0000)]
netdevsim: fix using uninitialized resources
When module is being initialized, __init() calls bus_register() and
driver_register().
These functions internally create various resources and sysfs files.
The sysfs files are used for basic operations(add/del device).
/sys/bus/netdevsim/new_device
/sys/bus/netdevsim/del_device
These sysfs files use netdevsim resources, they are mostly allocated
and initialized in ->probe() function, which is nsim_dev_probe().
But, sysfs files could be executed before ->probe() is finished.
So, accessing uninitialized data would occur.
Another problem is very similar.
/sys/bus/netdevsim/new_device internally creates sysfs files.
/sys/devices/netdevsim<id>/new_port
/sys/devices/netdevsim<id>/del_port
These sysfs files also use netdevsim resources, they are mostly allocated
and initialized in creating device routine, which is nsim_bus_dev_new().
But they also could be executed before nsim_bus_dev_new() is finished.
So, accessing uninitialized data would occur.
To fix these problems, this patch adds flags, which means whether the
operation is finished or not.
The flag variable 'nsim_bus_enable' means whether netdevsim bus was
initialized or not.
This is protected by nsim_bus_dev_list_lock.
The flag variable 'nsim_bus_dev->init' means whether nsim_bus_dev was
initialized or not.
This could be used in {new/del}_port_store() with no lock.
Test commands:
#SHELL1
modprobe netdevsim
while :
do
echo "1 1" > /sys/bus/netdevsim/new_device
echo "1 1" > /sys/bus/netdevsim/del_device
done
#SHELL2
while :
do
echo 1 > /sys/devices/netdevsim1/new_port
echo 1 > /sys/devices/netdevsim1/del_port
done
Fixes: f9d9db47d3ba ("netdevsim: add bus attributes to add new and delete devices") Fixes: 794b2c05ca1c ("netdevsim: extend device attrs to support port addition and deletion") Signed-off-by: Taehee Yoo <[email protected]> Signed-off-by: Jakub Kicinski <[email protected]>
Jakub Kicinski [Mon, 3 Feb 2020 23:07:26 +0000 (15:07 -0800)]
Merge branch 'bnxt_en-Bug-fixes'
Michael Chan says:
=====================
bnxt_en: Bug fixes
3 patches that fix some issues in the firmware reset logic, starting
with a small patch to refactor the code that re-enables SRIOV. The
last patch fixes a TC queue mapping issue.
====================
Michael Chan [Sun, 2 Feb 2020 07:41:38 +0000 (02:41 -0500)]
bnxt_en: Fix TC queue mapping.
The driver currently only calls netdev_set_tc_queue when the number of
TCs is greater than 1. Instead, the comparison should be greater than
or equal to 1. Even with 1 TC, we need to set the queue mapping.
This bug can cause warnings when the number of TCs is changed back to 1.
Fixes: 7809592d3e2e ("bnxt_en: Enable MSIX early in bnxt_init_one().") Signed-off-by: Michael Chan <[email protected]> Signed-off-by: Jakub Kicinski <[email protected]>
bnxt_en: Fix logic that disables Bus Master during firmware reset.
The current logic that calls pci_disable_device() in __bnxt_close_nic()
during firmware reset is flawed. If firmware is still alive, we're
disabling the device too early, causing some firmware commands to
not reach the firmware.
Fix it by moving the logic to bnxt_reset_close(). If firmware is
in fatal condition, we call pci_disable_device() before we free
any of the rings to prevent DMA corruption of the freed rings. If
firmware is still alive, we call pci_disable_device() after the
last firmware message has been sent.
Michael Chan [Sun, 2 Feb 2020 07:41:36 +0000 (02:41 -0500)]
bnxt_en: Fix RDMA driver failure with SRIOV after firmware reset.
bnxt_ulp_start() needs to be called before SRIOV is re-enabled after
firmware reset. Re-enabling SRIOV may consume all the resources and
may cause the RDMA driver to fail to get MSIX and other resources.
Fix it by calling bnxt_ulp_start() first before calling
bnxt_reenable_sriov().
We re-arrange the logic so that we call bnxt_ulp_start() and
bnxt_reenable_sriov() in proper sequence in bnxt_fw_reset_task() and
bnxt_open(). The former is the normal coordinated firmware reset sequence
and the latter is firmware reset while the function is down. This new
logic is now more straight forward and will now fix both scenarios.
Fixes: f3a6d206c25a ("bnxt_en: Call bnxt_ulp_stop()/bnxt_ulp_start() during error recovery.") Reported-by: Vasundhara Volam <[email protected]> Signed-off-by: Michael Chan <[email protected]> Signed-off-by: Jakub Kicinski <[email protected]>
Michael Chan [Sun, 2 Feb 2020 07:41:35 +0000 (02:41 -0500)]
bnxt_en: Refactor logic to re-enable SRIOV after firmware reset detected.
Put the current logic in bnxt_open() to re-enable SRIOV after detecting
firmware reset into a new function bnxt_reenable_sriov(). This call
needs to be invoked in the firmware reset path also in the next patch.
Fix the way modifiers are skipped while walking pointers. Otherwise second
level dereferences of 'const struct foo *' will be rejected by the verifier.
Michal Rostecki [Sun, 2 Feb 2020 11:02:00 +0000 (12:02 +0100)]
bpftool: Remove redundant "HAVE" prefix from the large INSN limit check
"HAVE" prefix is already applied by default to feature macros and before
this change, the large INSN limit macro had the incorrect name with
double "HAVE".
Nicolin Chen [Sat, 1 Feb 2020 02:01:24 +0000 (18:01 -0800)]
net: stmmac: Delete txtimer in suspend()
When running v5.5 with a rootfs on NFS, memory abort may happen in
the system resume stage:
Unable to handle kernel paging request at virtual address dead00000000012a
[dead00000000012a] address between user and kernel address ranges
pc : run_timer_softirq+0x334/0x3d8
lr : run_timer_softirq+0x244/0x3d8
x1 : ffff800011cafe80 x0 : dead000000000122
Call trace:
run_timer_softirq+0x334/0x3d8
efi_header_end+0x114/0x234
irq_exit+0xd0/0xd8
__handle_domain_irq+0x60/0xb0
gic_handle_irq+0x58/0xa8
el1_irq+0xb8/0x180
arch_cpu_idle+0x10/0x18
do_idle+0x1d8/0x2b0
cpu_startup_entry+0x24/0x40
secondary_start_kernel+0x1b4/0x208
Code: f9000693a9400660f9000020b4000040 (f9000401)
---[ end trace bb83ceeb4c482071 ]---
Kernel panic - not syncing: Fatal exception in interrupt
SMP: stopping secondary CPUs
SMP: failed to stop secondary CPUs 2-3
Kernel Offset: disabled
CPU features: 0x00002,2300aa30
Memory Limit: none
---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---
It's found that stmmac_xmit() and stmmac_resume() sometimes might
run concurrently, possibly resulting in a race condition between
mod_timer() and setup_timer(), being called by stmmac_xmit() and
stmmac_resume() respectively.
Since the resume() runs setup_timer() every time, it'd be safer to
have del_timer_sync() in the suspend() as the counterpart.
Linus Torvalds [Mon, 3 Feb 2020 22:27:33 +0000 (22:27 +0000)]
Merge branch 'for-5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu
Pull percpu updates from Dennis Zhou:
"Separate out variables that can be decrypted into their own page
anytime encryption can be enabled and fix __percpu annotations in
asm-generic for sparse"
* 'for-5.6' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu:
percpu: Separate decrypted varaibles anytime encryption can be enabled
percpu: fix __percpu annotation in asm-generic
Linus Torvalds [Mon, 3 Feb 2020 22:22:05 +0000 (22:22 +0000)]
Merge tag 'vfio-v5.6-rc1' of git://github.com/awilliam/linux-vfio
Pull VFIO updates from Alex Williamson:
- Fix nvlink error path (Alexey Kardashevskiy)
- Update nvlink and spapr to use mmgrab() (Julia Lawall)
- Update static declaration (Ben Dooks)
- Annotate __iomem to fix sparse warnings (Ben Dooks)
* tag 'vfio-v5.6-rc1' of git://github.com/awilliam/linux-vfio:
vfio: platform: fix __iomem in vfio_platform_amdxgbe.c
vfio/mdev: make create attribute static
vfio/spapr_tce: use mmgrab
vfio: vfio_pci_nvlink2: use mmgrab
vfio/spapr/nvlink2: Skip unpinning pages on error exit
Amir Goldstein [Mon, 3 Feb 2020 19:46:43 +0000 (21:46 +0200)]
SMB3: Backup intent flag missing from some more ops
When "backup intent" is requested on the mount (e.g. backupuid or
backupgid mount options), the corresponding flag was missing from
some of the operations.
Change all operations to use the macro cifs_create_options() to
set the backup intent flag if needed.
Linus Torvalds [Mon, 3 Feb 2020 22:10:18 +0000 (22:10 +0000)]
Merge tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux
Pull clk updates from Stephen Boyd:
"There are a few changes to the core framework this time around, in
addition to the normal collection of driver updates to support new
SoCs, fix incorrect data, and convert various drivers to clk_hw based
APIs.
In the core, we allow clk_ops::init() to return an error code now so
that we can fail clk registration if the callback does something like
fail to allocate memory. We also add a new "terminate" clk_op so that
things done in clk_ops::init() can be undone, e.g. free memory. We
also spit out a warning now when critical clks fail to enable and we
support changing clk rates and enable/disable state through debugfs
when developers compile the kernel themselves.
On the driver front, we get support for what seems like a lot of
Qualcomm and NXP SoCs given that those vendors dominate the diffstat.
There are a couple new drivers for Xilinx and Amlogic SoCs too. The
updates are all small things like fixing the way glitch free muxes
switch parents, avoiding div-by-zero problems, or fixing data like
parent names. See the updates section below for more details.
Finally, the "basic" clk types have been converted to support
specifying parents with clk_hw pointers. This work includes an
overhaul of the fixed-rate clk type to be more modern by using clk_hw
APIs.
Core:
- Let clk_ops::init() return an error code
- Add a clk_ops::terminate() callback to undo clk_ops::init()
- Warn about critical clks that fail to enable or prepare
- Support dangerous debugfs actions on clks with dead code
New Drivers:
- Support for Xilinx Versal platform clks
- Display clk controller on qcom sc7180
- Video clk controller on qcom sc7180
- Graphics clk controller on qcom sc7180
- CPU PLLs for qcom msm8916
- Move qcom msm8974 gfx3d clk to RPM control
- Display port clk support on qcom sdm845 SoCs
- Global clk controller on qcom ipq6018
- Add a driver for BCLK of Freescale SAI cores
- Add cam, vpe and sgx clock support for TI dra7
- Add aess clock support for TI omap5
- Enable clks for CPUfreq on Allwinner A64 SoCs
- Add Amlogic meson8b DDR clock controller
- Add input clocks to Amlogic meson8b controllers
- Add SPIBSC (SPI FLASH) clock on Renesas RZ/A2
- i.MX8MP clk driver support
Updates:
- Convert gpio, fixed-factor, mux, gate, divider basic clks to hw
based APIs
- Detect more PRMCU variants in ux500 driver
- Adjust the composite clk type to new way of describing clk parents
- Fixes for clk controllers on qcom msm8998 SoCs
- Fix gmac main clock for TI dra7
- Move TI dra7-atl clock header to correct location
- Fix hidden node name dependency on TI clkctrl clocks
- Fix Amlogic meson8b mali clock update using the glitch free mux
- Fix Amlogic pll driver division by zero at init
- Prepare for split of Renesas R-Car H3 ES1.x and ES2.0+ config
symbols
- Switch more i.MX clk drivers to clk_hw based APIs
- Disable non-functional divider between pll4_audio_div and
pll4_post_div on imx6q
- Fix watchdog2 clock name typo in imx7ulp clock driver
- Set CLK_GET_RATE_NOCACHE flag for DRAM related clocks on i.MX8M
SoCs
- Suppress bind attrs for i.MX8M clock driver
- Add a big comment in imx8qxp-lpcg driver to tell why
devm_platform_ioremap_resource() shouldn't be used for the driver
- A correction on i.MX8MN usb1_ctrl parent clock setting"
* tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux: (140 commits)
dt/bindings: clk: fsl,plldig: Drop 'bindings' from schema id
clk: ls1028a: Fix warning on clamp() usage
clk: qoriq: add ls1088a hwaccel clocks support
clk: ls1028a: Add clock driver for Display output interface
dt/bindings: clk: Add YAML schemas for LS1028A Display Clock bindings
clk: fsl-sai: new driver
dt-bindings: clock: document the fsl-sai driver
clk: composite: add _register_composite_pdata() variants
clk: qcom: rpmh: Sort OF match table
dt-bindings: fix warnings in validation of qcom,gcc.yaml
dt-binding: fix compilation error of the example in qcom,gcc.yaml
clk: zynqmp: Add support for clock with CLK_DIVIDER_POWER_OF_TWO flag
clk: zynqmp: Fix divider calculation
clk: zynqmp: Add support for get max divider
clk: zynqmp: Warn user if clock user are more than allowed
clk: zynqmp: Extend driver for versal
dt-bindings: clock: Add bindings for versal clock driver
clk: ti: clkctrl: Fix hidden dependency to node name
clk: ti: add clkctrl data dra7 sgx
clk: ti: omap5: Add missing AESS clock
...
Trond Myklebust [Sun, 2 Feb 2020 22:53:54 +0000 (17:53 -0500)]
NFS: Directory page cache pages need to be locked when read
When a NFS directory page cache page is removed from the page cache,
its contents are freed through a call to nfs_readdir_clear_array().
To prevent the removal of the page cache entry until after we've
finished reading it, we must take the page lock.
Trond Myklebust [Sun, 2 Feb 2020 22:53:53 +0000 (17:53 -0500)]
NFS: Fix memory leaks and corruption in readdir
nfs_readdir_xdr_to_array() must not exit without having initialised
the array, so that the page cache deletion routines can safely
call nfs_readdir_clear_array().
Furthermore, we should ensure that if we exit nfs_readdir_filler()
with an error, we free up any page contents to prevent a leak
if we try to fill the page again.
Trond Myklebust [Sun, 2 Feb 2020 22:57:07 +0000 (17:57 -0500)]
NFS: Replace various occurrences of kstrndup() with kmemdup_nul()
When we already know the string length, it is more efficient to
use kmemdup_nul().
Signed-off-by: Trond Myklebust <[email protected]>
[Anna - Changes to super.c were already made during fscontext conversion] Signed-off-by: Anna Schumaker <[email protected]>
Trond Myklebust [Mon, 27 Jan 2020 14:58:19 +0000 (09:58 -0500)]
NFSv4: Limit the total number of cached delegations
Delegations can be expensive to return, and can cause scalability issues
for the server. Let's therefore try to limit the number of inactive
delegations we hold.
Once the number of delegations is above a certain threshold, start
to return them on close.
dt-bindings: clk: qcom: Fix self-validation, split, and clean cruft
The 'qcom,gcc.yaml' file failed self-validation (dt_binding_check)
because it required a property to be either (3 entries big),
(3 entries big), or (7 entries big), but not more than one of those
things. That didn't make a ton of sense.
This patch splits all of the exceptional device trees (AKA those that
would have needed if/then/else rules) from qcom,gcc.yaml. It also
cleans up some cruft found while doing that.
After this lands, this worked for me atop clk-next with just the known
error about msm8998:
for f in \
Documentation/devicetree/bindings/clock/qcom,gcc-apq8064.yaml \
Documentation/devicetree/bindings/clock/qcom,gcc-ipq8074.yaml \
Documentation/devicetree/bindings/clock/qcom,gcc-msm8996.yaml \
Documentation/devicetree/bindings/clock/qcom,gcc-msm8998.yaml \
Documentation/devicetree/bindings/clock/qcom,gcc-qcs404.yaml \
Documentation/devicetree/bindings/clock/qcom,gcc-sc7180.yaml \
Documentation/devicetree/bindings/clock/qcom,gcc-sm8150.yaml \
Documentation/devicetree/bindings/clock/qcom,gcc.yaml; do \
ARCH=arm64 make dtbs_check DT_SCHEMA_FILES=$f; \
done
I then picked this patch atop linux-next (next-20200129) and ran:
# Delete broken yaml:
rm Documentation/devicetree/bindings/pci/intel-gw-pcie.yaml
ARCH=arm64 make dt_binding_check | grep 'clock/qcom'
...and that didn't seem to indicate problems.
Arbitrary decisions made (yell if you want changed):
- Left all the older devices (where clocks / clock-names weren't
specified) in a single file.
- Didn't make clocks "required" for msm8996 but left them as listed.
This seems a little weird but it matches the old binding.
Misc cleanups as part of this patch:
- Fixed schema id to not have "bindings/" as per Rob [1].
- Listed include files as per Stephen.
- sm8150 was claimed to be same set of clocks as sc7180, but driver
and dts appear to say that "bi_tcxo_ao" doesn't exist. Fixed.
- In "apq8064", "#thermal-sensor-cells" was missing the "#".
- Got rid of "|" at the end of top description since spacing doesn't
matter.
- Changed indentation to consistently 2 spaces (it was 3 in some
places).
- Added period at the end of protected-clocks description.
- No space before ":".
- Updated sc7180/sm8150 example to use the 'qcom,rpmh.h' include.
- Updated sc7180/sm8150 example to use larger address/size cells as
per reality.
- Updated sc7180/sm8150 example to point to the sleep_clk rather than
<0>.
- Made it so that gcc-ipq8074 didn't require #power-domain-cells since
actual dts didn't have it and I got no hits from:
git grep _GDSC include/dt-bindings/clock/qcom,gcc-ipq8074.h
- Made it so that gcc-qcs404 didn't require #power-domain-cells since
actual dts didn't have it and I got no hits from:
git grep _GDSC include/dt-bindings/clock/qcom,gcc-qcs404.h
Noticed, but not done in this patch (volunteers needed):
- Add "aud_ref_clk" to sm8150 bindings / dts even though I found a
reference to it in "gcc-sm8150.c".
- Fix node name in actual ipq8074 to be "clock-controller" (it's gcc).
- Since the example doesn't need phandes to exist, in msm8998 could
just make up places providing some of the clocks currently bogused
out with <0>.
- On msm8998 clocks are listed as required but current dts doesn't
have them.
Stephen Boyd [Tue, 28 Jan 2020 19:33:29 +0000 (11:33 -0800)]
clk: qcom: Don't overwrite 'cfg' in clk_rcg2_dfs_populate_freq()
The DFS frequency table logic overwrites 'cfg' while detecting the
parent clk and then later on in clk_rcg2_dfs_populate_freq() we use that
same variable to figure out the mode of the clk, either MND or not. Add
a new variable to hold the parent clk bit so that 'cfg' is left
untouched for use later.
This fixes problems in detecting the supported frequencies for any clks
in DFS mode.
Stephen Boyd [Mon, 3 Feb 2020 05:25:07 +0000 (21:25 -0800)]
dt/bindings: clk: fsl,plldig: Drop 'bindings' from schema id
Having 'bindings' in here causes a warning when checking the schema.
Documentation/devicetree/bindings/clock/fsl,plldig.yaml:
$id: relative path/filename doesn't match actual path or filename
expected: http://devicetree.org/schemas/clock/fsl,plldig.yaml#
Stephen Boyd [Mon, 3 Feb 2020 05:25:06 +0000 (21:25 -0800)]
clk: ls1028a: Fix warning on clamp() usage
These constants are used in clamp() with the value being clamped an
unsigned long. Make them unsigned long defines so that clamp() doesn't
complain about comparing different types.
In file included from include/linux/list.h:9,
from include/linux/kobject.h:19,
from include/linux/of.h:17,
from include/linux/clk-provider.h:9,
from drivers/clk/clk-plldig.c:8:
drivers/clk/clk-plldig.c: In function 'plldig_determine_rate':
include/linux/kernel.h:835:29: warning: comparison of distinct pointer types lacks a cast
835 | (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
|
Jakub Kicinski [Mon, 3 Feb 2020 18:26:23 +0000 (10:26 -0800)]
Merge tag 'rxrpc-fixes-20200203' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
David Howells says:
====================
RxRPC fixes
Here are a number of fixes for AF_RXRPC:
(1) Fix a potential use after free in rxrpc_put_local() where it was
accessing the object just put to get tracing information.
(2) Fix insufficient notifications being generated by the function that
queues data packets on a call. This occasionally causes recvmsg() to
stall indefinitely.
(3) Fix a number of packet-transmitting work functions to hold an active
count on the local endpoint so that the UDP socket doesn't get
destroyed whilst they're calling kernel_sendmsg() on it.
(4) Fix a NULL pointer deref that stemmed from a call's connection pointer
being cleared when the call was disconnected.
Changes:
v2: Removed a couple of BUG() statements that got added.
====================