diff options
| author |   Matthew Wilcox <mawilcox@microsoft.com> | 2018-06-07 17:05:13 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2018-06-07 17:34:34 -0700 |
| commit | 128227e7fe4087b60f1bd31f762e61237eb23790 (patch) | |
| tree | ccf03475b150751d98f4f901339a3871dafe8240 /mm/slab.c | |
| parent | net/9p/trans_xen.c: don't inclide rwlock.h directly (diff) | |
| download | wireguard-linux-128227e7fe4087b60f1bd31f762e61237eb23790.tar.xz wireguard-linux-128227e7fe4087b60f1bd31f762e61237eb23790.zip | |
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.c | 2 |
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) { |