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 | |
| parent | e56ee574bc46b9734066008b3dc105bd7d4cbc0c (diff) | |
| download | linux-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>
| -rw-r--r-- | mm/slab.c | 2 | ||||
| -rw-r--r-- | mm/slob.c | 4 | ||||
| -rw-r--r-- | mm/slub.c | 2 |
3 files changed, 7 insertions, 1 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) { diff --git a/mm/slob.c b/mm/slob.c index 623e8a5c46ce..307c2c9feb44 100644 --- a/mm/slob.c +++ b/mm/slob.c @@ -555,8 +555,10 @@ static void *slob_alloc_node(struct kmem_cache *c, gfp_t flags, int node) flags, node); } - if (b && c->ctor) + if (b && c->ctor) { + WARN_ON_ONCE(flags & __GFP_ZERO); c->ctor(b); + } kmemleak_alloc_recursive(b, c->size, 1, c->flags, flags); return b; diff --git a/mm/slub.c b/mm/slub.c index 44aa7847324a..dc960401ce90 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2444,6 +2444,8 @@ static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags, struct kmem_cache_cpu *c = *pc; struct page *page; + WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO)); + freelist = get_partial(s, flags, node, c); if (freelist) |