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| author | Andrea Arcangeli <aarcange@redhat.com> | 2010-04-23 13:17:39 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-05-12 15:02:32 -0700 |
| commit | 90fb67fc9fa7e23a98c4f627253634de42546a2e (patch) | |
| tree | fbf45c28ec0bbd50c37a48d93b78e22510cba678 /mm | |
| parent | 73791763dbad4d68a1d36b7f2ded26d0214bf09c (diff) | |
| download | lwn-90fb67fc9fa7e23a98c4f627253634de42546a2e.tar.gz lwn-90fb67fc9fa7e23a98c4f627253634de42546a2e.zip | |
memcg: fix prepare migration
commit 93d5c9be1ddd57d4063ce463c9ac2be1e5ee14f1 upstream.
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/memcontrol.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 954032b80bed..dff33797bef4 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2215,12 +2215,12 @@ 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, page); css_put(&mem->css); } - *ptr = mem; return ret; } |