From: Oleg Nesterov <oleg@redhat.com>
To: Sasha Levin <sasha.levin@oracle.com>
Cc: David Howells <dhowells@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
richard@nod.at, Dave Jones <davej@redhat.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: kernel: signal: NULL ptr deref when killing process
Date: Thu, 21 Aug 2014 19:11:26 +0200 [thread overview]
Message-ID: <20140821171126.GA27140@redhat.com> (raw)
In-Reply-To: <53F60E58.2050708@oracle.com>
On 08/21, Sasha Levin wrote:
>
> On 08/20/2014 10:12 AM, Oleg Nesterov wrote:
> > On 08/20, Sasha Levin wrote:
> >> >
> >> > Hi all,
> >> >
> >> > While fuzzing with trinity inside a KVM tools guest running the latest -next
> >> > kernel, I've stumbled on the following spew:
> > Thanks...
> >
> > looks like, kill_ok_by_cred()->__task_cred(t) returns NULL at first glance.
> > perhaps you can show the result of "make kernel/signal.s" to be sure? Or at
> > least the full "objdump -d kernel/signal.o".
>
> Attached.
Thanks.
Yes, t->real_cred == NULL (r14).
Interestingly, t->signal is NULL too (rcx). And ->signal must be never NULL.
So it looks like this task_struct was reallocated/reused. Or corrupted.
t == 0xffff880546803000 (r12), this doesn't look wrong.
Oleg.
prev parent reply other threads:[~2014-08-21 17:13 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-20 11:18 kernel: signal: NULL ptr deref when killing process Sasha Levin
2014-08-20 14:12 ` Oleg Nesterov
2014-08-20 15:06 ` Oleg Nesterov
2014-08-20 15:30 ` Oleg Nesterov
2014-08-21 16:22 ` David Howells
2014-08-21 17:17 ` Oleg Nesterov
2014-08-27 3:38 ` Sasha Levin
2014-08-27 14:16 ` Oleg Nesterov
2014-08-21 15:20 ` Sasha Levin
2014-08-21 17:11 ` Oleg Nesterov [this message]
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