Re: WARNING in try_charge

Tetsuo Handa
2018-08-05T11:33:20Z

On 2018/08/04 22:45, Tetsuo Handa wrote:
> syzbot is hitting WARN(1) because of mem_cgroup_out_of_memory() == false.

Since syzbot found a syz reproducer, I asked syzbot to try two patches.

Setting MMF_OOM_SKIP under oom_lock to prevent from races
( https://syzkaller.appspot.com/x/patch.diff?x=10fb3fd0400000 ) was not sufficient.

Waiting until __mmput() completes (with timeout using OOM score feedback)
( https://syzkaller.appspot.com/x/patch.diff?x=101e449c400000 ) solved this race.