From: Jiri Slaby <jslaby@suse.cz>
To: Steven Rostedt <rostedt@goodmis.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Hurley <peter@hurleysoftware.com>,
Greg KH <gregkh@linuxfoundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
stable <stable@vger.kernel.org>,
lwn@lwn.net
Subject: Re: BUG: unable to handle kernel paging request from pty_write [was: Linux 4.4.2]
Date: Fri, 26 Feb 2016 09:25:30 +0100 [thread overview]
Message-ID: <56D00BFA.6060406@suse.cz> (raw)
In-Reply-To: <20160225142338.42e46f2c@gandalf.local.home>
On 02/25/2016, 08:23 PM, Steven Rostedt wrote:
> On Thu, 25 Feb 2016 11:09:35 -0800
> Linus Torvalds <torvalds@linux-foundation.org> wrote:
>
>
>> Jiri, were you messing around with tracing when this happened? Or
>> maybe shutting down CPU's? There was a RCU locking problem with CPU
>> shutdown, maybe this is one of the symptoms. The fix for that is
>> recent, and not in 4.4.2.
>>
>> Adding Steven Rostedt to the cc. Steven, does that look like a possible case?
>
> Possible: yes. Likely: no
>
> The recent fix would require shutting down a CPU at the same time as a
> tracepoint is enabled or disabled. Rather difficult to hit, but easier
> on a virtual machine. If Jiri was not enabling/disabling tracepoints or
> shutting down CPUs, then it would not be the bug.
As this is an automatic build, I very doubt a CPU was offlined or
tracepoints enabled. So I see it even less unlikely this to happen
concurrently.
> But as the comm of the bug is gdb and this running on a virtual
> machine, I think the bug may be elsewhere. Corrupt stack possibly?
Seems so (broken stack frame pointer link), as is indicated in other e-mail.
thanks,
--
js
suse labs
next prev parent reply other threads:[~2016-02-26 8:25 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-17 20:37 Linux 4.4.2 Greg KH
2016-02-17 20:37 ` Greg KH
2016-02-25 10:12 ` BUG: unable to handle kernel paging request from pty_write [was: Linux 4.4.2] Jiri Slaby
2016-02-25 18:40 ` Peter Hurley
2016-02-25 19:09 ` Linus Torvalds
2016-02-25 19:23 ` Steven Rostedt
2016-02-26 8:25 ` Jiri Slaby [this message]
2016-02-25 20:32 ` Peter Hurley
2016-02-25 20:51 ` Linus Torvalds
2016-02-25 21:32 ` Jiri Slaby
2016-02-25 22:33 ` Peter Hurley
2016-02-26 0:38 ` Peter Hurley
2016-02-26 8:45 ` Jiri Slaby
2016-02-26 0:38 ` Linus Torvalds
2016-02-26 8:56 ` Jiri Slaby
2016-02-26 9:23 ` Jiri Slaby
2016-02-26 9:50 ` Jiri Slaby
2016-02-26 16:34 ` Greg KH
2016-02-26 17:12 ` Linus Torvalds
2016-02-29 15:45 ` Paolo Bonzini
2016-02-26 17:52 ` Peter Hurley
2016-02-25 21:43 ` Peter Hurley
2016-02-25 22:00 ` Jiri Kosina
2016-02-26 8:31 ` Jiri Slaby
2016-02-26 8:15 ` Jiri Slaby
2016-02-26 18:05 Linus Torvalds
2016-02-26 18:17 ` Borislav Petkov
2016-02-26 18:18 ` Peter Hurley
2016-02-26 19:44 ` Linus Torvalds
2016-02-26 19:59 ` Robert Święcki
2016-02-29 7:39 ` Jiri Slaby
2016-02-29 12:43 ` Henrique de Moraes Holschuh
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