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| author | Michal Hocko <mhocko@suse.cz> | 2014-07-30 16:08:33 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-08-07 14:52:37 -0700 |
| commit | 1b3225dad61487de348f66fd91e11f58b14406d6 (patch) | |
| tree | cc035d71ad341134b835060484ab3afdeca3c8a4 | |
| parent | e7598322f418926b9aa3d814e2c88ae7995fa61a (diff) | |
| download | lwn-1b3225dad61487de348f66fd91e11f58b14406d6.tar.gz lwn-1b3225dad61487de348f66fd91e11f58b14406d6.zip | |
memcg: oom_notify use-after-free fix
commit 2bcf2e92c3918ce62ab4e934256e47e9a16d19c3 upstream.
Paul Furtado has reported the following GPF:
general protection fault: 0000 [#1] SMP
Modules linked in: ipv6 dm_mod xen_netfront coretemp hwmon x86_pkg_temp_thermal crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel ablk_helper cryptd lrw gf128mul glue_helper aes_x86_64 microcode pcspkr ext4 jbd2 mbcache raid0 xen_blkfront
CPU: 3 PID: 3062 Comm: java Not tainted 3.16.0-rc5 #1
task: ffff8801cfe8f170 ti: ffff8801d2ec4000 task.ti: ffff8801d2ec4000
RIP: e030:mem_cgroup_oom_synchronize+0x140/0x240
RSP: e02b:ffff8801d2ec7d48 EFLAGS: 00010283
RAX: 0000000000000001 RBX: ffff88009d633800 RCX: 000000000000000e
RDX: fffffffffffffffe RSI: ffff88009d630200 RDI: ffff88009d630200
RBP: ffff8801d2ec7da8 R08: 0000000000000012 R09: 00000000fffffffe
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88009d633800
R13: ffff8801d2ec7d48 R14: dead000000100100 R15: ffff88009d633a30
FS: 00007f1748bb4700(0000) GS:ffff8801def80000(0000) knlGS:0000000000000000
CS: e033 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00007f4110300308 CR3: 00000000c05f7000 CR4: 0000000000002660
Call Trace:
pagefault_out_of_memory+0x18/0x90
mm_fault_error+0xa9/0x1a0
__do_page_fault+0x478/0x4c0
do_page_fault+0x2c/0x40
page_fault+0x28/0x30
Code: 44 00 00 48 89 df e8 40 ca ff ff 48 85 c0 49 89 c4 74 35 4c 8b b0 30 02 00 00 4c 8d b8 30 02 00 00 4d 39 fe 74 1b 0f 1f 44 00 00 <49> 8b 7e 10 be 01 00 00 00 e8 42 d2 04 00 4d 8b 36 4d 39 fe 75
RIP mem_cgroup_oom_synchronize+0x140/0x240
Commit fb2a6fc56be6 ("mm: memcg: rework and document OOM waiting and
wakeup") has moved mem_cgroup_oom_notify outside of memcg_oom_lock
assuming it is protected by the hierarchical OOM-lock.
Although this is true for the notification part the protection doesn't
cover unregistration of event which can happen in parallel now so
mem_cgroup_oom_notify can see already unlinked and/or freed
mem_cgroup_eventfd_list.
Fix this by using memcg_oom_lock also in mem_cgroup_oom_notify.
Addresses https://bugzilla.kernel.org/show_bug.cgi?id=80881
Fixes: fb2a6fc56be6 (mm: memcg: rework and document OOM waiting and wakeup)
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Reported-by: Paul Furtado <paulfurtado91@gmail.com>
Tested-by: Paul Furtado <paulfurtado91@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
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@linuxfoundation.org>
| -rw-r--r-- | mm/memcontrol.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 5b6b0039f725..9b35da28b587 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -5670,8 +5670,12 @@ static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg) { struct mem_cgroup_eventfd_list *ev; + spin_lock(&memcg_oom_lock); + list_for_each_entry(ev, &memcg->oom_notify, list) eventfd_signal(ev->eventfd, 1); + + spin_unlock(&memcg_oom_lock); return 0; } |