linux-stable.git/include/linux/stackdepot.h, branch v6.8.4

lib/stackdepot: fix comment in include/linux/stackdepot.h

2023-12-29T19:58:42+00:00

As stack traces can now be evicted from the stack depot, remove the
comment saying that they are never removed.

Link: https://lkml.kernel.org/r/0ebe712d91f8d302a8947d3c9e9123bc2b1b8440.1703020707.git.andreyknvl@google.com
Fixes: 108be8def46e ("lib/stackdepot: allow users to evict stack traces")
Signed-off-by: Andrey Konovalov 
Reviewed-by: Marco Elver 
Cc: Alexander Potapenko 
Cc: Dmitry Vyukov 
Cc: Evgenii Stepanov 
Cc: Tetsuo Handa 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

lib/stackdepot: allow users to evict stack traces

2023-12-11T00:51:47+00:00

Add stack_depot_put, a function that decrements the reference counter on a
stack record and removes it from the stack depot once the counter reaches
0.

Internally, when removing a stack record, the function unlinks it from the
hash table bucket and returns to the freelist.

With this change, the users of stack depot can call stack_depot_put when
keeping a stack trace in the stack depot is not needed anymore.  This
allows avoiding polluting the stack depot with irrelevant stack traces and
thus have more space to store the relevant ones before the stack depot
reaches its capacity.

Link: https://lkml.kernel.org/r/1d1ad5692ee43d4fc2b3fd9d221331d30b36123f.1700502145.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 
Cc: Alexander Potapenko 
Cc: Dmitry Vyukov 
Cc: Evgenii Stepanov 
Cc: Marco Elver 
Cc: Oscar Salvador 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

lib/stackdepot: add refcount for records

2023-12-11T00:51:46+00:00

Add a reference counter for how many times a stack records has been
  added to stack depot.

Add a new STACK_DEPOT_FLAG_GET flag to stack_depot_save_flags that
  instructs the stack depot to increment the refcount.

Do not yet decrement the refcount; this is implemented in one of the
  following patches.

Do not yet enable any users to use the flag to avoid overflowing the
  refcount.

This is preparatory patch for implementing the eviction of stack records
  from the stack depot.

Link: https://lkml.kernel.org/r/a3fc14a2359d019d2a008d4ff8b46a665371ffee.1700502145.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 
Reviewed-by: Alexander Potapenko 
Cc: Dmitry Vyukov 
Cc: Evgenii Stepanov 
Cc: Marco Elver 
Cc: Oscar Salvador 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

lib/stackdepot, kasan: add flags to __stack_depot_save and rename

2023-12-11T00:51:46+00:00

Change the bool can_alloc argument of __stack_depot_save to a u32
  argument that accepts a set of flags.

The following patch will add another flag to stack_depot_save_flags
  besides the existing STACK_DEPOT_FLAG_CAN_ALLOC.

Also rename the function to stack_depot_save_flags, as
  __stack_depot_save is a cryptic name,

Link: https://lkml.kernel.org/r/645fa15239621eebbd3a10331e5864b718839512.1700502145.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 
Reviewed-by: Alexander Potapenko 
Cc: Dmitry Vyukov 
Cc: Evgenii Stepanov 
Cc: Marco Elver 
Cc: Oscar Salvador 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

lib/stackdepot: move documentation comments to stackdepot.h

2023-02-17T04:43:52+00:00

Move all interface- and usage-related documentation comments to
include/linux/stackdepot.h.

It makes sense to have them in the header where they are available to
the interface users.

[akpm@linux-foundation.org: grammar fix, per Alexander]
Link: https://lkml.kernel.org/r/fbfee41495b306dd8881f9b1c1b80999c885e82f.1676063693.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 
Reviewed-by: Alexander Potapenko 
Signed-off-by: Andrew Morton

lib/stackdepot: various comments clean-ups

2023-02-17T04:43:52+00:00

Clean up comments in include/linux/stackdepot.h and lib/stackdepot.c:

1. Rework the initialization comment in stackdepot.h.
2. Rework the header comment in stackdepot.c.
3. Various clean-ups for other comments.

Also adjust whitespaces for find_stack and depot_alloc_stack call sites.

No functional changes.

Link: https://lkml.kernel.org/r/5836231b7954355e2311fc9b5870f697ea8e1f7d.1676063693.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 
Reviewed-by: Alexander Potapenko 
Signed-off-by: Andrew Morton

lib/stacktrace, kasan, kmsan: rework extra_bits interface

2023-02-17T04:43:51+00:00

The current implementation of the extra_bits interface is confusing:
passing extra_bits to __stack_depot_save makes it seem that the extra
bits are somehow stored in stack depot. In reality, they are only
embedded into a stack depot handle and are not used within stack depot.

Drop the extra_bits argument from __stack_depot_save and instead provide
a new stack_depot_set_extra_bits function (similar to the exsiting
stack_depot_get_extra_bits) that saves extra bits into a stack depot
handle.

Update the callers of __stack_depot_save to use the new interace.

This change also fixes a minor issue in the old code: __stack_depot_save
does not return NULL if saving stack trace fails and extra_bits is used.

Link: https://lkml.kernel.org/r/317123b5c05e2f82854fc55d8b285e0869d3cb77.1676063693.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 
Reviewed-by: Alexander Potapenko 
Signed-off-by: Andrew Morton

lib/stackdepot, mm: rename stack_depot_want_early_init

2023-02-17T04:43:49+00:00

Rename stack_depot_want_early_init to stack_depot_request_early_init.

The old name is confusing, as it hints at returning some kind of intention
of stack depot.  The new name reflects that this function requests an
action from stack depot instead.

No functional changes.

[akpm@linux-foundation.org: update mm/kmemleak.c]
Link: https://lkml.kernel.org/r/359f31bf67429a06e630b4395816a967214ef753.1676063693.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 
Reviewed-by: Alexander Potapenko 
Acked-by: Vlastimil Babka 
Signed-off-by: Andrew Morton

lib/stackdepot: put functions in logical order

2023-02-17T04:43:48+00:00

Patch series "lib/stackdepot: fixes and clean-ups", v2.

A set of fixes, comments, and clean-ups I came up with while reading
the stack depot code.


This patch (of 18):

Put stack depot functions' declarations and definitions in a more logical
order:

1. Functions that save stack traces into stack depot.
2. Functions that fetch and print stack traces.
3. stack_depot_get_extra_bits that operates on stack depot handles
   and does not interact with the stack depot storage.

No functional changes.

Link: https://lkml.kernel.org/r/cover.1676063693.git.andreyknvl@google.com
Link: https://lkml.kernel.org/r/daca1319b665d826b94c596b992a8d8117846147.1676063693.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov 
Reviewed-by: Alexander Potapenko 
Cc: Evgenii Stepanov 
Cc: Marco Elver 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

stackdepot: reserve 5 extra bits in depot_stack_handle_t

2022-10-03T21:03:18+00:00

Some users (currently only KMSAN) may want to use spare bits in
depot_stack_handle_t.  Let them do so by adding @extra_bits to
__stack_depot_save() to store arbitrary flags, and providing
stack_depot_get_extra_bits() to retrieve those flags.

Also adapt KASAN to the new prototype by passing extra_bits=0, as KASAN
does not intend to store additional information in the stack handle.

Link: https://lkml.kernel.org/r/20220915150417.722975-3-glider@google.com
Signed-off-by: Alexander Potapenko 
Reviewed-by: Marco Elver 
Cc: Alexander Viro 
Cc: Alexei Starovoitov 
Cc: Andrey Konovalov 
Cc: Andrey Konovalov 
Cc: Andy Lutomirski 
Cc: Arnd Bergmann 
Cc: Borislav Petkov 
Cc: Christoph Hellwig 
Cc: Christoph Lameter 
Cc: David Rientjes 
Cc: Dmitry Vyukov 
Cc: Eric Biggers 
Cc: Eric Biggers 
Cc: Eric Dumazet 
Cc: Greg Kroah-Hartman 
Cc: Herbert Xu 
Cc: Ilya Leoshkevich 
Cc: Ingo Molnar 
Cc: Jens Axboe 
Cc: Joonsoo Kim 
Cc: Kees Cook 
Cc: Mark Rutland 
Cc: Matthew Wilcox 
Cc: Michael S. Tsirkin 
Cc: Pekka Enberg 
Cc: Peter Zijlstra 
Cc: Petr Mladek 
Cc: Stephen Rothwell 
Cc: Steven Rostedt 
Cc: Thomas Gleixner 
Cc: Vasily Gorbik 
Cc: Vegard Nossum 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton