提交 73736e03 编写于 作者: E Eric Dumazet 提交者: Pekka Enberg

slub: fix a possible memleak in __slab_alloc()

Zhihua Che reported a possible memleak in slub allocator on
CONFIG_PREEMPT=y builds.

It is possible current thread migrates right before disabling irqs in
__slab_alloc(). We must check again c->freelist, and perform a normal
allocation instead of scratching c->freelist.

Many thanks to Zhihua Che for spotting this bug, introduced in 2.6.39

V2: Its also possible an IRQ freed one (or several) object(s) and
populated c->freelist, so its not a CONFIG_PREEMPT only problem.

Cc: <stable@vger.kernel.org>        [2.6.39+]
Reported-by: NZhihua Che <zhihua.che@gmail.com>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Acked-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NPekka Enberg <penberg@kernel.org>
上级 25f4379b
......@@ -2169,6 +2169,11 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
goto new_slab;
}
/* must check again c->freelist in case of cpu migration or IRQ */
object = c->freelist;
if (object)
goto load_freelist;
stat(s, ALLOC_SLOWPATH);
do {
......
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