blob: 87a49aea6e24a16fe95f599162a65693ea15188f (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
|
From c25b1c3dffca9191001f97e64c9be8e1ff861c0a Mon Sep 17 00:00:00 2001
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Tue, 13 Dec 2011 04:57:06 +0100
Subject: [PATCH 042/130] 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>
---
mm/slub.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c
index ed3334d..1a919f0 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 {
--
1.7.7.4
|
