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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2011-12-13 04:57:06 +0100 |
|---|---|---|
| committer | Pekka Enberg <penberg@kernel.org> | 2011-12-13 22:11:21 +0200 |
| commit | 73736e0387ba0e6d2b703407b4d26168d31516a7 (patch) | |
| tree | 448f2d85f82462096d55c93f15cea9876665faaa | |
| parent | 25f4379b8c79066c4be0e5995f37f5265733b801 (diff) | |
| download | lwn-73736e0387ba0e6d2b703407b4d26168d31516a7.tar.gz lwn-73736e0387ba0e6d2b703407b4d26168d31516a7.zip | |
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: 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>
| -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 108ed03fb422..5e410a95abaf 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2169,6 +2169,11 @@ 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 { |