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From: Thomas Gleixner <tglx@linutronix.de>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Andy Lutomirski <luto@kernel.org>,
	syzbot 
	<bot+1f445b1009b8eeededa30fe62ccf685f2ec9d155@syzkaller.appspotmail.com>,
	Borislav Petkov <bp@suse.de>,
	Dmitry Safonov <dsafonov@virtuozzo.com>,
	Peter Anvin <hpa@zytor.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Kyle Huey <me@kylehuey.com>, Ingo Molnar <mingo@redhat.com>,
	syzkaller-bugs@googlegroups.com,
	the arch/x86 maintainers <x86@kernel.org>
Subject: Re: BUG: unable to handle kernel paging request in __switch_to
Date: Fri, 15 Dec 2017 10:49:43 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.20.1712151047400.1702@nanos> (raw)
In-Reply-To: <CACT4Y+YBMFq0JdwF2K7xfGC7sPxdJOzj9V2TPEKGuJgqaknu9A@mail.gmail.com>

On Fri, 15 Dec 2017, Dmitry Vyukov wrote:
> I've built this exact kernel and here is __switch_to disasm:
> https://gist.githubusercontent.com/dvyukov/8137559f7da08fbe32f9018972a4498c/raw/0ef2abf723b117f0d0f0306fd50e216d50c5cecb/gistfile1.txt
> 
> __switch_to+0x95b seems to point to (?):
> 
> ffffffff81252f6b: 0f 1f 44 00 00        nopl   0x0(%rax,%rax,1)
> 
> which is branch target alignment nop.

Which is a place holder for a trace point as Linus pointed out and the
'faulting' instruction which is int3 shows that there is a tracepoint
install/remove in progress. Are your test cases fiddling with tracepoints?

Thanks,

	tglx

      parent reply	other threads:[~2017-12-15  9:49 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <001a1145e8548cbd3d055f73374f@google.com>
2017-12-14 17:12 ` Thomas Gleixner
2017-12-14 18:42   ` Linus Torvalds
2017-12-14 18:54     ` Andy Lutomirski
2017-12-14 19:28       ` Linus Torvalds
2017-12-14 21:27         ` Andy Lutomirski
2017-12-14 21:39           ` Linus Torvalds
2017-12-15  9:07             ` Dmitry Vyukov
2017-12-15  9:13               ` Dmitry Vyukov
2017-12-15  9:38                 ` Dmitry Vyukov
2017-12-15  9:40                   ` Wanpeng Li
2017-12-15  9:51                   ` David Hildenbrand
2017-12-15  9:58                     ` Wanpeng Li
2017-12-15 10:02                       ` Dmitry Vyukov
2017-12-15 16:16                         ` Andy Lutomirski
2017-12-15 16:44                           ` Ingo Molnar
2017-12-19 11:48                             ` Dmitry Vyukov
2017-12-15  9:49               ` Thomas Gleixner [this message]

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