summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorArnd Bergmann <arnd@arndb.de>2016-12-13 03:41:35 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-13 05:55:06 +0300
commit84582c8ab9479ffa4532afa95ab8d8f96b5478dc (patch)
tree3dfcb024b303d52f04b64503ab86ff7ca46917fb
parent89e364db71fb5e7fc8d93228152abfa67daf35fa (diff)
downloadlinux-84582c8ab9479ffa4532afa95ab8d8f96b5478dc.tar.xz
slub: avoid false-postive warning
The slub allocator gives us some incorrect warnings when CONFIG_PROFILE_ANNOTATED_BRANCHES is set, as the unlikely() macro prevents it from seeing that the return code matches what it was before: mm/slub.c: In function `kmem_cache_free_bulk': mm/slub.c:262:23: error: `df.s' may be used uninitialized in this function [-Werror=maybe-uninitialized] mm/slub.c:2943:3: error: `df.cnt' may be used uninitialized in this function [-Werror=maybe-uninitialized] mm/slub.c:2933:4470: error: `df.freelist' may be used uninitialized in this function [-Werror=maybe-uninitialized] mm/slub.c:2943:3: error: `df.tail' may be used uninitialized in this function [-Werror=maybe-uninitialized] I have not been able to come up with a perfect way for dealing with this, the three options I see are: - add a bogus initialization, which would increase the runtime overhead - replace unlikely() with unlikely_notrace() - remove the unlikely() annotation completely I checked the object code for a typical x86 configuration and the last two cases produce the same result, so I went for the last one, which is the simplest. Link: http://lkml.kernel.org/r/20161024155704.3114445-1-arnd@arndb.de Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Vladimir Davydov <vdavydov.dev@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Laura Abbott <labbott@fedoraproject.org> Cc: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/slub.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/slub.c b/mm/slub.c
index 4a861f265cd7..067598a00849 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3076,7 +3076,7 @@ void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
struct detached_freelist df;
size = build_detached_freelist(s, size, p, &df);
- if (unlikely(!df.page))
+ if (!df.page)
continue;
slab_free(df.s, df.page, df.freelist, df.tail, df.cnt,_RET_IP_);