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lib/stackdepot: adjust DEPOT_POOLS_CAP for KMSAN

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KMSAN is frequently used in fuzzing scenarios and thus saves a lot of
stack traces.  As KMSAN does not support evicting stack traces from the
stack depot, the stack depot capacity might be reached quickly with large
stack records.

Adjust the maximum number of stack depot pools for this case.

The average size of a stack trace saved into the stack depot is ~16
frames.  Thus, adjust the maximum pools number accordingly to keep the
maximum number of stack traces that can be saved into the stack depot
similar to the one that was allowed before the stack trace eviction
changes.

Link: https://lkml.kernel.org/r/301a115cf7ce8ddb42ef6de9151c2bb76ba728fc.1700502145.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Andrey Konovalov 2023-11-20 18:47:20 +01:00 committed by Andrew Morton
parent 773688a6cb
commit bd9d9624b7
1 changed files with 10 additions and 0 deletions
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10
lib/stackdepot.c
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@ -41,7 +41,17 @@
#define DEPOT_OFFSET_BITS (DEPOT_POOL_ORDER + PAGE_SHIFT - DEPOT_STACK_ALIGN)
#define DEPOT_POOL_INDEX_BITS (DEPOT_HANDLE_BITS - DEPOT_OFFSET_BITS - \
STACK_DEPOT_EXTRA_BITS)
#if IS_ENABLED(CONFIG_KMSAN) && CONFIG_STACKDEPOT_MAX_FRAMES >= 32
/*
* KMSAN is frequently used in fuzzing scenarios and thus saves a lot of stack
* traces. As KMSAN does not support evicting stack traces from the stack
* depot, the stack depot capacity might be reached quickly with large stack
* records. Adjust the maximum number of stack depot pools for this case.
*/
#define DEPOT_POOLS_CAP (8192 * (CONFIG_STACKDEPOT_MAX_FRAMES / 16))
#else
#define DEPOT_POOLS_CAP 8192
#endif
#define DEPOT_MAX_POOLS \
(((1LL << (DEPOT_POOL_INDEX_BITS)) < DEPOT_POOLS_CAP) ? \
(1LL << (DEPOT_POOL_INDEX_BITS)) : DEPOT_POOLS_CAP)