From: Marco Elver elver@google.com
mainline inclusion from mainline-v5.12-rc5 commit 9551158069ba8fcc893798d42dc4f978b62ef60f category: feature bugzilla: 181005 https://gitee.com/openeuler/kernel/issues/I4EUY7
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Because memblock allocations are registered with kmemleak, the KFENCE pool was seen by kmemleak as one large object. Later allocations through kfence_alloc() that were registered with kmemleak via slab_post_alloc_hook() would then overlap and trigger a warning. Therefore, once the pool is initialized, we can remove (free) it from kmemleak again, since it should be treated as allocator-internal and be seen as "free memory".
The second problem is that kmemleak is passed the rounded size, and not the originally requested size, which is also the size of KFENCE objects. To avoid kmemleak scanning past the end of an object and trigger a KFENCE out-of-bounds error, fix the size if it is a KFENCE object.
For simplicity, to avoid a call to kfence_ksize() in slab_post_alloc_hook() (and avoid new IS_ENABLED(CONFIG_DEBUG_KMEMLEAK) guard), just call kfence_ksize() in mm/kmemleak.c:create_object().
Link: https://lkml.kernel.org/r/20210317084740.3099921-1-elver@google.com Signed-off-by: Marco Elver elver@google.com Reported-by: Luis Henriques lhenriques@suse.de Reviewed-by: Catalin Marinas catalin.marinas@arm.com Tested-by: Luis Henriques lhenriques@suse.de Cc: Alexander Potapenko glider@google.com Cc: Dmitry Vyukov dvyukov@google.com Cc: Andrey Konovalov andreyknvl@google.com Cc: Jann Horn jannh@google.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Peng Liu liupeng256@huawei.com Reviewed-by: Kefeng Wang wangkefeng.wang@huawei.com
Signed-off-by: Chen Jun chenjun102@huawei.com --- mm/kfence/core.c | 9 +++++++++ mm/kmemleak.c | 3 ++- 2 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/mm/kfence/core.c b/mm/kfence/core.c index 3b8ec938470a..d53c91f881a4 100644 --- a/mm/kfence/core.c +++ b/mm/kfence/core.c @@ -12,6 +12,7 @@ #include <linux/debugfs.h> #include <linux/kcsan-checks.h> #include <linux/kfence.h> +#include <linux/kmemleak.h> #include <linux/list.h> #include <linux/lockdep.h> #include <linux/memblock.h> @@ -480,6 +481,14 @@ static bool __init kfence_init_pool(void) addr += 2 * PAGE_SIZE; }
+ /* + * The pool is live and will never be deallocated from this point on. + * Remove the pool object from the kmemleak object tree, as it would + * otherwise overlap with allocations returned by kfence_alloc(), which + * are registered with kmemleak through the slab post-alloc hook. + */ + kmemleak_free(__kfence_pool); + return true;
err: diff --git a/mm/kmemleak.c b/mm/kmemleak.c index c0014d3b91c1..fe6e3ae8e8c6 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -97,6 +97,7 @@ #include <linux/atomic.h>
#include <linux/kasan.h> +#include <linux/kfence.h> #include <linux/kmemleak.h> #include <linux/memory_hotplug.h>
@@ -589,7 +590,7 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size, atomic_set(&object->use_count, 1); object->flags = OBJECT_ALLOCATED; object->pointer = ptr; - object->size = size; + object->size = kfence_ksize((void *)ptr) ?: size; object->excess_ref = 0; object->min_count = min_count; object->count = 0; /* white color initially */