[merged] kfence-move-the-size-check-to-the-beginning-of-__kfence_alloc.patch removed from -mm tree
From: akpm@linux-foundation.org
Date: 2021-07-27 19:35:11
Also in:
mm-commits
The patch titled
Subject: kfence: move the size check to the beginning of __kfence_alloc()
has been removed from the -mm tree. Its filename was
kfence-move-the-size-check-to-the-beginning-of-__kfence_alloc.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Alexander Potapenko <glider@google.com>
Subject: 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: <redacted> [5.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/kfence/core.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
--- a/mm/kfence/core.c~kfence-move-the-size-check-to-the-beginning-of-__kfence_alloc
+++ a/mm/kfence/core.c@@ -734,6 +734,13 @@ void kfence_shutdown_cache(struct kmem_c 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 * if (!READ_ONCE(kfence_enabled)) return NULL; - if (size > PAGE_SIZE) - return NULL; - return kfence_guarded_alloc(s, size, flags); }
_ Patches currently in -mm which might be from glider@google.com are