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authorMatthew Wilcox <mawilcox@microsoft.com>2018-06-07 17:05:13 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-07 17:34:34 -0700
commit128227e7fe4087b60f1bd31f762e61237eb23790 (patch)
treeccf03475b150751d98f4f901339a3871dafe8240 /mm/slab.c
parente56ee574bc46b9734066008b3dc105bd7d4cbc0c (diff)
downloadlinux-128227e7fe4087b60f1bd31f762e61237eb23790.tar.bz2
slab: __GFP_ZERO is incompatible with a constructor
__GFP_ZERO requests that the object be initialised to all-zeroes, while the purpose of a constructor is to initialise an object to a particular pattern. We cannot do both. Add a warning to catch any users who mistakenly pass a __GFP_ZERO flag when allocating a slab with a constructor. Link: http://lkml.kernel.org/r/20180412191322.GA21205@bombadil.infradead.org Fixes: d07dbea46405 ("Slab allocators: support __GFP_ZERO in all allocators") Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slab.c')
-rw-r--r--mm/slab.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/slab.c b/mm/slab.c
index 2f308253c3d7..c1fe8099b3cd 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -2665,6 +2665,7 @@ static struct page *cache_grow_begin(struct kmem_cache *cachep,
invalid_mask, &invalid_mask, flags, &flags);
dump_stack();
}
+ WARN_ON_ONCE(cachep->ctor && (flags & __GFP_ZERO));
local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
check_irq_off();
@@ -3071,6 +3072,7 @@ static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
gfp_t flags, void *objp, unsigned long caller)
{
+ WARN_ON_ONCE(cachep->ctor && (flags & __GFP_ZERO));
if (!objp)
return objp;
if (cachep->flags & SLAB_POISON) {