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Koen Kooi
189ce92b4c
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net> Signed-off-by: Denys Dmytriyenko <denys@ti.com>
48 lines
1.4 KiB
Diff
48 lines
1.4 KiB
Diff
From 71490e8f6f58ec56533554888983ce09d6ee5cb1 Mon Sep 17 00:00:00 2001
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From: Eric Dumazet <eric.dumazet@gmail.com>
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Date: Tue, 13 Dec 2011 04:57:06 +0100
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Subject: [PATCH 042/129] slub: fix a possible memleak in __slab_alloc()
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commit 73736e0387ba0e6d2b703407b4d26168d31516a7 upstream.
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Zhihua Che reported a possible memleak in slub allocator on
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CONFIG_PREEMPT=y builds.
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It is possible current thread migrates right before disabling irqs in
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__slab_alloc(). We must check again c->freelist, and perform a normal
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allocation instead of scratching c->freelist.
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Many thanks to Zhihua Che for spotting this bug, introduced in 2.6.39
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V2: Its also possible an IRQ freed one (or several) object(s) and
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populated c->freelist, so its not a CONFIG_PREEMPT only problem.
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Reported-by: Zhihua Che <zhihua.che@gmail.com>
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Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
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Acked-by: Christoph Lameter <cl@linux.com>
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Signed-off-by: Pekka Enberg <penberg@kernel.org>
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Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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---
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mm/slub.c | 5 +++++
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1 file changed, 5 insertions(+)
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diff --git a/mm/slub.c b/mm/slub.c
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index ed3334d..1a919f0 100644
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--- a/mm/slub.c
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+++ b/mm/slub.c
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@@ -2166,6 +2166,11 @@ redo:
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goto new_slab;
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}
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+ /* must check again c->freelist in case of cpu migration or IRQ */
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+ object = c->freelist;
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+ if (object)
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+ goto load_freelist;
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+
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stat(s, ALLOC_SLOWPATH);
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do {
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--
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1.7.9.5
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