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From: Borislav Petkov <bp@alien8.de>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>,
	Marco Elver <elver@google.com>,
	syzbot <syzbot+ce179bc99e64377c24bc@syzkaller.appspotmail.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>, Jiri Olsa <jolsa@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Ingo Molnar <mingo@redhat.com>,
	Namhyung Kim <namhyung@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	the arch/x86 maintainers <x86@kernel.org>,
	clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: general protection fault in perf_misc_flags
Date: Tue, 29 Sep 2020 10:33:36 +0200	[thread overview]
Message-ID: <20200929083336.GA21110@zn.tnic> (raw)
In-Reply-To: <20200928202353.GI1685@zn.tnic>

On Mon, Sep 28, 2020 at 10:23:53PM +0200, Borislav Petkov wrote:
> 2020/09/28 22:21:01 VMs 3, executed 179, corpus cover 11792, corpus signal 10881, max signal 19337, crashes 0, repro 0

Ok, so far triggered two things:

WARNING in f2fs_is_valid_blkaddr	1	2020/09/29 10:27	reproducing
WARNING in reiserfs_put_super		1	2020/09/28 22:42

you've probably seen them already.

Anyway, next question. Let's say I trigger the corruption: is there a
way to stop the guest VM which has triggered it so that I'm able to
examine it with gdb?

What about kdump? Can I dump the guest memory either with kdump or
through the qemu monitor (I believe there's a command to dump memory) so
that it can be poked at?

Because as it is, we don't have a reproducer and as I see it, the fuzzing simply
gets restarted:

2020/09/29 10:27:03 vm-3: crash: WARNING in f2fs_is_valid_blkaddr
...
2020/09/29 10:27:05 loop: phase=1 shutdown=false instances=1/4 [3] repro: pending=0 reproducing=1 queued=1
2020/09/29 10:27:05 loop: starting instance 3

so it would be good to be able to say, when a vm encounters a crash, it
should be stopped immediately so that the guest can be examined through
qemu's gdb interface, i.e.,

-gdb tcp::<portnum>

or so?

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

  reply	other threads:[~2020-09-29  8:33 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-19  8:32 general protection fault in perf_misc_flags syzbot
2020-09-19 11:08 ` Borislav Petkov
2020-09-21  5:54   ` Dmitry Vyukov
2020-09-21  8:08     ` Dmitry Vyukov
2020-09-21 20:59       ` Nick Desaulniers
2020-09-21 22:13         ` Borislav Petkov
2020-09-22 18:56           ` Nick Desaulniers
2020-09-22 19:29             ` Borislav Petkov
2020-09-23  9:03             ` Borislav Petkov
2020-09-23  9:24               ` Dmitry Vyukov
2020-09-23 10:34                 ` Borislav Petkov
2020-09-23 15:20                   ` Dmitry Vyukov
2020-09-25 12:22                     ` Dmitry Vyukov
2020-09-26  0:32                       ` Nick Desaulniers
2020-09-26  6:46                         ` Dmitry Vyukov
2020-09-26 17:14                         ` Borislav Petkov
2020-09-26 11:21                     ` Borislav Petkov
2020-09-26 12:08                       ` Dmitry Vyukov
2020-09-22  5:15         ` Dmitry Vyukov
2020-09-22  5:16         ` Dmitry Vyukov
2020-09-27 14:57 ` Borislav Petkov
2020-09-28  5:18   ` Dmitry Vyukov
2020-09-28  6:06     ` Dmitry Vyukov
2020-09-28  8:38       ` Borislav Petkov
2020-09-28  8:40         ` Dmitry Vyukov
2020-09-28  8:54           ` Borislav Petkov
2020-09-28 10:33             ` Dmitry Vyukov
2020-09-28 20:23               ` Borislav Petkov
2020-09-29  8:33                 ` Borislav Petkov [this message]
2020-09-29 13:29                   ` Dmitry Vyukov
2020-09-30 16:17                     ` Borislav Petkov
2020-09-30 16:23                       ` Dmitry Vyukov
2020-09-30 16:29                         ` Dmitry Vyukov
2020-09-30 16:31                         ` Borislav Petkov
2020-10-01 10:23                           ` Dmitry Vyukov
2020-10-01 11:05                             ` Borislav Petkov
2020-09-28 20:51               ` Nick Desaulniers
2020-09-28 21:19                 ` Andy Lutomirski
2020-09-28  7:25     ` Marco Elver
2020-09-28 20:32     ` Nick Desaulniers
2020-09-29 13:27       ` Dmitry Vyukov

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