Re: frequent lockups in 3.18rc4

From: Linus Torvalds
Date: Mon Dec 01 2014 - 12:53:22 EST


On Mon, Dec 1, 2014 at 9:10 AM, Will Deacon <will.deacon@xxxxxxx> wrote:
>
> So I don't even have binfmt-misc compiled in. The two handlers I have are
> BINFMT_ELF and BINFMT_SCRIPT, but they both check for headers that we won't
> get back from oom_score afaict.

Hmm. So I can't even get that "oom_score" file to be executable in the
first place, which should mean that execve() should terminate very
quickly with an EACCES error.

The fact that you have a "flush_work()" that is waiting for completion
is interesting. Maybe the odd new thread is a worker thread for some
modprobe or similar, and we . There's that whole

request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2))

which ends up creating a new work. Maybe the flush_work() is waiting
for that whole mess. Adding Tejun to the cc, since there *were*
changes to workqueues etc since 3.16..

Tejun, full thread on lkml, I'm assuming you can find it in your mail archives..

Linus
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