linux-kernel - Re: [PATCH] oom: Make coredump interruptible

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20100613155354.GA8428@redhat.com>
Date:	Sun, 13 Jun 2010 17:53:54 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Cc:	Roland McGrath <roland@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>,
	linux-mm <linux-mm@...ck.org>,
	David Rientjes <rientjes@...gle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Nick Piggin <npiggin@...e.de>
Subject: Re: [PATCH] oom: Make coredump interruptible

On 06/13, KOSAKI Motohiro wrote:
>
> > On 06/04, Oleg Nesterov wrote:
> > >
> > Perhaps something like below makes sense for now.
>
> Probably, this works. at least I don't find any problems.
> But umm... Do you mean we can't implement per-process oom flags?

Sorry, can't understand what you mean.

> example,
> 	1) back to implement signal->oom_victim
> 	   because We are using SIGKILL for OOM and struct signal
> 	   naturally represent signal target.

Yes, but if this process participates in the coredump, we should find
the right thread, or mark mm or mm->core_state.

In fact, I was never sure that oom-kill should kill the single process.
Perhaps it should kill all tasks using the same ->mm instead. But this
is another story.

> 	2) mm->nr_oom_killed_task
> 	   just avoid simple flag. instead counting number of tasks of
> 	   oom-killed.

again, can't understand.

> I think both avoid your explained problem. Am I missing something?

I guess that I am missing something ;) Please clarify?

> But, again, I have no objection to your patch. because I really hope to
> fix coredump vs oom issue.

Yes, I think this is important. And if we keep the PF_EXITING check in
select_bad_process(), it should be fixed so that at least the coredump
can't fool it. And the "p != current" is obviously not right too.

I'll try to do something next week, the patches should be simple.

Oleg.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/