The patch titled
Subject: mm/slab: rerform init_on_free earlier
has been added to the -mm tree. Its filename is
mm-slab-perform-init_on_free-earlier.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-slab-perform-init_on_free-earlier.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-slab-perform-init_on_free-earlier.patch
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------------------------------------------------------
From: Alexander Popov <alex.popov@xxxxxxxxx>
Subject: mm/slab: rerform init_on_free earlier
Currently in CONFIG_SLAB init_on_free happens too late, and heap objects
go to the heap quarantine not being erased.
Lets move init_on_free clearing before calling kasan_slab_free(). In that
case heap quarantine will store erased objects, similarly to CONFIG_SLUB=y
behavior.
Link: https://lkml.kernel.org/r/20201210183729.1261524-1-alex.popov@xxxxxxxxx
Signed-off-by: Alexander Popov <alex.popov@xxxxxxxxx>
Reviewed-by: Alexander Potapenko <glider@xxxxxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
Acked-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/slab.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/mm/slab.c~mm-slab-perform-init_on_free-earlier
+++ a/mm/slab.c
@@ -3416,6 +3416,9 @@ free_done:
static __always_inline void __cache_free(struct kmem_cache *cachep, void *objp,
unsigned long caller)
{
+ if (unlikely(slab_want_init_on_free(cachep)))
+ memset(objp, 0, cachep->object_size);
+
/* Put the object into the quarantine, don't touch it for now. */
if (kasan_slab_free(cachep, objp, _RET_IP_))
return;
@@ -3434,8 +3437,6 @@ void ___cache_free(struct kmem_cache *ca
struct array_cache *ac = cpu_cache_get(cachep);
check_irq_off();
- if (unlikely(slab_want_init_on_free(cachep)))
- memset(objp, 0, cachep->object_size);
kmemleak_free_recursive(objp, cachep->flags);
objp = cache_free_debugcheck(cachep, objp, caller);
memcg_slab_free_hook(cachep, &objp, 1);
_
Patches currently in -mm which might be from alex.popov@xxxxxxxxx are
mm-slab-perform-init_on_free-earlier.patch
