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kasan: use stack_depot_put for tag-based modes

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Make tag-based KASAN modes evict stack traces from the stack depot once
they are evicted from the stack ring.

Internally, pass STACK_DEPOT_FLAG_GET to stack_depot_save_flags (via
kasan_save_stack) to increment the refcount when saving a new entry to
stack ring and call stack_depot_put when removing an entry from stack
ring.

Link: https://lkml.kernel.org/r/b4773e5c1b0b9df6826ec0b65c1923feadfa78e5.1700502145.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: 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 18:47:18 +01:00 committed by Andrew Morton
parent 7d88e4f768
commit f816938bff
1 changed files with 8 additions and 2 deletions
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10
mm/kasan/tags.c
View file

@ -97,12 +97,13 @@ static void save_stack_info(struct kmem_cache *cache, void *object,
gfp_t gfp_flags, bool is_free)
{
unsigned long flags;
depot_stack_handle_t stack;
depot_stack_handle_t stack, old_stack;
u64 pos;
struct kasan_stack_ring_entry *entry;
void *old_ptr;
stack = kasan_save_stack(gfp_flags, STACK_DEPOT_FLAG_CAN_ALLOC);
stack = kasan_save_stack(gfp_flags,
STACK_DEPOT_FLAG_CAN_ALLOC | STACK_DEPOT_FLAG_GET);
/*
* Prevent save_stack_info() from modifying stack ring
@ -121,6 +122,8 @@ static void save_stack_info(struct kmem_cache *cache, void *object,
if (!try_cmpxchg(&entry->ptr, &old_ptr, STACK_RING_BUSY_PTR))
goto next; /* Busy slot. */
old_stack = entry->stack;
entry->size = cache->object_size;
entry->pid = current->pid;
entry->stack = stack;
@ -129,6 +132,9 @@ static void save_stack_info(struct kmem_cache *cache, void *object,
entry->ptr = object;
read_unlock_irqrestore(&stack_ring.lock, flags);
if (old_stack)
stack_depot_put(old_stack);
}
void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags)