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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2011-12-13 04:57:06 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2012-01-25 16:13:21 -0800 |
| commit | 65722fdd70758e2f1ac30f42f54c056631062fd5 (patch) | |
| tree | d5656ab2c66b2bd8a4ce580e2b7225ac550d80c2 /mm/slub.c | |
| parent | 858452ff4198a85874a7ee97da454d4a5d67938e (diff) | |
| download | lwn-65722fdd70758e2f1ac30f42f54c056631062fd5.tar.gz lwn-65722fdd70758e2f1ac30f42f54c056631062fd5.zip | |
slub: fix a possible memleak in __slab_alloc()
commit 73736e0387ba0e6d2b703407b4d26168d31516a7 upstream.
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.
Reported-by: Zhihua Che <zhihua.che@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'mm/slub.c')
| -rw-r--r-- | mm/slub.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/mm/slub.c b/mm/slub.c index ed3334d9b6da..1a919f0150f5 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2166,6 +2166,11 @@ redo: 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 { |