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]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20140821171126.GA27140@redhat.com \
--to=oleg@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=davej@redhat.com \
--cc=dhowells@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=richard@nod.at \
--cc=sasha.levin@oracle.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.