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From: Peter Zijlstra <peterz@infradead.org>
To: Vince Weaver <vincent.weaver@maine.edu>
Cc: 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>
Subject: Re: perf: perf_fuzzer quickly locks up on 4.15-rc7
Date: Thu, 11 Jan 2018 20:11:25 +0100	[thread overview]
Message-ID: <20180111191125.GG2369@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20180111170347.GG6176@hirez.programming.kicks-ass.net>

On Thu, Jan 11, 2018 at 06:03:47PM +0100, Peter Zijlstra wrote:
> > On Thu, 11 Jan 2018, Vince Weaver wrote:
> > [  823.919729] BUG: unable to handle kernel paging request at ffff88011a7a1000
> > [  823.926928] IP: 0x7fbda0042b3c
> > 
> > I'm dumping vmlinux and can't find address 0x7fbda0042b3c at all.
> 
> That's a user address..

> > [  823.930123] PGD 22ea067 P4D 22ea067 PUD 22ed067 PMD 11a520063 PTE 800000011a7a1063
> > [  823.938012] Oops: 0002 [#1] SMP PTI
> > [  823.968898] CPU: 1 PID: 17688 Comm: perf_fuzzer Not tainted 4.15.0-rc7+ #211
> > [  823.976152] Hardware name: AOpen   DE7000/nMCP7ALPx-DE R1.06 Oct.19.2012, BIOS 080015  10/19/2012
> > [  823.985259] RIP: 0033:0x7fbda0042b3c
> > [  823.989002] RSP: 002b:00007ffed7fa46c8 EFLAGS: 00010246
> > [  823.994434] RAX: 000000000000462d RBX: 000000000000000c RCX: 00007fbda0042b3c
> > [  824.001786] RDX: 0000000000000000 RSI: 00007ffed7fa46dc RDI: 000000000000462d
> > [  824.009135] RBP: 00007ffed7fa46e0 R08: 00007fbda032e0e4 R09: 0000000000000000
> > [  824.016483] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401950
> > [  824.023832] R13: 00007ffed7fa6ae0 R14: 0000000000000000 R15: 0000000000000000
> > [  824.031198] FS:  00007fbda0540700(0000) GS:ffff88011fc80000(0000) knlGS:0000000000000000
> > [  824.039530] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > [  824.045477] CR2: ffff88011a7a1000 CR3: 000000011a998000 CR4: 00000000000407e0
> > [  824.052827] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > [  824.060176] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
> > [  824.072767] CR2: ffff88011a7a1000
> > [  824.076248] ---[ end trace 31d5336f74638197 ]--

So its faulting while looking up the userspace page tables, so
something buggered. The CR3 has bit 12 clear so its a kernel CR3, which
is also somewhat puzzling.

Oooh, right, its the CR3 from when we report the OOPS, which is less
than useful.

I can't get further than that the page-tables are screwed..

  parent reply	other threads:[~2018-01-11 19:11 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
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 [this message]
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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