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authorAndrea Arcangeli <aarcange@redhat.com>2010-04-23 13:17:39 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2010-04-24 11:31:24 -0700
commit93d5c9be1ddd57d4063ce463c9ac2be1e5ee14f1 (patch)
tree65455c40ec8c701789d8f16b825e5c290633c910 /mm/memcontrol.c
parentcac36f707119b792b2396aed371d6b5cdc194890 (diff)
downloadvexpress-lsk-93d5c9be1ddd57d4063ce463c9ac2be1e5ee14f1.tar.gz
memcg: fix prepare migration
If a signal is pending (task being killed by sigkill) __mem_cgroup_try_charge will write NULL into &mem, and css_put will oops on null pointer dereference. BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 IP: [<ffffffff810fc6cc>] mem_cgroup_prepare_migration+0x7c/0xc0 PGD a5d89067 PUD a5d8a067 PMD 0 Oops: 0000 [#1] SMP last sysfs file: /sys/devices/platform/microcode/firmware/microcode/loading CPU 0 Modules linked in: nfs lockd nfs_acl auth_rpcgss sunrpc acpi_cpufreq pcspkr sg [last unloaded: microcode] Pid: 5299, comm: largepages Tainted: G W 2.6.34-rc3 #3 Penryn1600SLI-110dB/To Be Filled By O.E.M. RIP: 0010:[<ffffffff810fc6cc>] [<ffffffff810fc6cc>] mem_cgroup_prepare_migration+0x7c/0xc0 [nishimura@mxp.nes.nec.co.jp: fix merge issues] Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r--mm/memcontrol.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f4ede99c8b9..6c755de385f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2429,11 +2429,11 @@ int mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
}
unlock_page_cgroup(pc);
+ *ptr = mem;
if (mem) {
- ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false);
+ ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, ptr, false);
css_put(&mem->css);
}
- *ptr = mem;
return ret;
}