From bd9d9624b7136b69d892597b6a8cc482341e415a Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Mon, 20 Nov 2023 18:47:20 +0100 Subject: [PATCH] lib/stackdepot: adjust DEPOT_POOLS_CAP for KMSAN 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 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.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/lib/stackdepot.c b/lib/stackdepot.c index c1b31160f4b4..870cce2f4cbd 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -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)