diff options
| author | Alexander Potapenko <glider@google.com> | 2021-07-23 15:50:11 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-07-23 17:43:28 -0700 |
| commit | 235a85cb32bb123854ad31de46fdbf04c1d57cda (patch) | |
| tree | 20de2e4c1293425ab5f2566e1525ef70e2981e20 /mm | |
| parent | 32ae8a0669392248a92d7545a7363004543f3932 (diff) | |
kfence: move the size check to the beginning of __kfence_alloc()
Check the allocation size before toggling kfence_allocation_gate.
This way allocations that can't be served by KFENCE will not result in
waiting for another CONFIG_KFENCE_SAMPLE_INTERVAL without allocating
anything.
Link: https://lkml.kernel.org/r/20210714092222.1890268-1-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Suggested-by: Marco Elver <elver@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org> [5.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/kfence/core.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/mm/kfence/core.c b/mm/kfence/core.c index d7666ace9d2e..2623ff401a10 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -734,6 +734,13 @@ void kfence_shutdown_cache(struct kmem_cache *s) void *__kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags) { /* + * Perform size check before switching kfence_allocation_gate, so that + * we don't disable KFENCE without making an allocation. + */ + if (size > PAGE_SIZE) + return NULL; + + /* * allocation_gate only needs to become non-zero, so it doesn't make * sense to continue writing to it and pay the associated contention * cost, in case we have a large number of concurrent allocations. @@ -757,9 +764,6 @@ void *__kfence_alloc(struct kmem_cache *s, size_t size, gfp_t flags) if (!READ_ONCE(kfence_enabled)) return NULL; - if (size > PAGE_SIZE) - return NULL; - return kfence_guarded_alloc(s, size, flags); } |