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From: Josh Poimboeuf <jpoimboe@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>,
	Ingo Molnar <mingo@kernel.org>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andy Lutomirski <luto@kernel.org>
Subject: Re: perf: perf_fuzzer quickly locks up on 4.15-rc7
Date: Wed, 10 Jan 2018 23:25:38 -0600	[thread overview]
Message-ID: <20180111052538.2qhj6oxnc24xumhk@treble> (raw)
In-Reply-To: <20180109170716.bqmexpmywwr4bwuv@treble>

On Tue, Jan 09, 2018 at 11:07:16AM -0600, Josh Poimboeuf wrote:
> On Tue, Jan 09, 2018 at 05:05:51PM +0100, Peter Zijlstra wrote:
> > On Tue, Jan 09, 2018 at 10:56:52AM -0500, Vince Weaver wrote:
> > > On Tue, 9 Jan 2018, Peter Zijlstra wrote:
> > > 
> > > > So CONFIG_PAGE_TABLE_ISOLATION=y and booting with "pti=off" makes it
> > > > 'work', right?
> > > 
> > > yes.  Previously I was changing CONFIG_PAGE_TABLE_ISOLATION and 
> > > recompiling, but just now I booted with it set to yes and pti=off and the 
> > > fuzzer has been running fine for a half hour (usually it crashes in under 
> > > 5 minutes).

For the crash, you might try enabling CONFIG_DEBUG_ENTRY and seeing if
that gives you any output.

> > > I did see these in the logs which I don't think I've seen before.
> > > 
> > > WARNING: stack recursion on stack type 2
> > > WARNING: can't dereference iret registers at 000000000783fea8 for ip paranoid_entry+0x2e/0x90
> > > WARNING: can't dereference registers at 00000000f0698d17 for ip paranoid_entry+0x4c/0x90
> > > WARNING: stack going in the wrong direction? ip=native_sched_clock+0x9/0x90

This all looks very weird.  The stack pointers -- 000000000783fea8 and
00000000f0698d17 -- are obviously very wrong.  I will try to recreate
locally.

-- 
Josh

  reply	other threads:[~2018-01-11  5:25 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-08 16:12 perf: perf_fuzzer quickly locks up on 4.15-rc7 Vince Weaver
2018-01-08 17:30 ` Ingo Molnar
2018-01-08 20:29   ` Vince Weaver
2018-01-09 10:25     ` Peter Zijlstra
2018-01-09 13:26       ` Peter Zijlstra
2018-01-09 13:36         ` Peter Zijlstra
2018-01-09 13:44         ` Vince Weaver
2018-01-09 15:12           ` Peter Zijlstra
2018-01-09 15:24             ` Vince Weaver
2018-01-09 15:33               ` Peter Zijlstra
2018-01-09 15:56                 ` Vince Weaver
2018-01-09 16:05                   ` Peter Zijlstra
2018-01-09 17:07                     ` Josh Poimboeuf
2018-01-11  5:25                       ` Josh Poimboeuf [this message]
2018-01-11 19:00                         ` Vince Weaver
2018-01-11 19:21                           ` Josh Poimboeuf
2018-01-11 19:50                             ` Peter Zijlstra
2018-01-11 19:57                               ` Vince Weaver
2018-01-11 20:43                                 ` Vince Weaver
2018-05-01 13:29                             ` perf: fuzzer causes stack going in wrong direction warnings Vince Weaver
2018-05-01 13:58                               ` Josh Poimboeuf
2018-05-01 19:59                                 ` Vince Weaver
2018-05-01 22:04                                   ` Josh Poimboeuf
2018-05-02 20:50                                     ` Josh Poimboeuf
2018-05-04 14:35                                       ` Vince Weaver
2018-05-04 16:25                                         ` Josh Poimboeuf
2018-05-04 17:00                                           ` Vince Weaver
2018-05-05 15:38                                           ` Vince Weaver
2018-05-05 18:29                                             ` Josh Poimboeuf
2018-05-06 23:49                                               ` Josh Poimboeuf
2018-05-10 13:48                                                 ` Peter Zijlstra
2018-05-10 14:27                                                   ` Josh Poimboeuf
2018-05-10 23:16                                                   ` Josh Poimboeuf
2018-01-09 16:16                 ` perf: perf_fuzzer quickly locks up on 4.15-rc7 Ingo Molnar
2018-01-09 16:20                   ` Peter Zijlstra
2018-01-09 17:18                 ` Vince Weaver
2018-01-10 15:28                   ` Vince Weaver
2018-01-09 16:14             ` Peter Zijlstra
2018-01-09 17:53               ` Steven Rostedt
2018-01-09 18:02                 ` Peter Zijlstra
2018-01-09 18:09                   ` Steven Rostedt
2018-01-09 19:53                     ` Peter Zijlstra
2018-01-11  9:13           ` Peter Zijlstra
2018-01-11 15:26             ` Vince Weaver
2018-01-11 15:38               ` Peter Zijlstra
2018-01-11 16:41                 ` Vince Weaver
2018-01-11 16:58                   ` Vince Weaver
2018-01-11 17:03                     ` Peter Zijlstra
2018-01-11 18:04                       ` Vince Weaver
2018-01-11 18:20                         ` Vince Weaver
2018-01-11 19:01                           ` Peter Zijlstra
2018-01-11 19:11                       ` Peter Zijlstra
2018-01-11 20:15                         ` Vince Weaver
2018-01-11 20:40                           ` Vince Weaver
2018-01-11 20:57                             ` Peter Zijlstra
2018-01-12 19:48                               ` Vince Weaver
2018-01-11 20:42                           ` Peter Zijlstra
2018-01-11 15:29             ` Peter Zijlstra

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