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Subject: Re: BUG: unable to handle kernel paging request from pty_write [was:
 Linux 4.4.2]
To: Peter Hurley <peter@hurleysoftware.com>
References: <20160217203730.GA14820@kroah.com> <56CED373.9060603@suse.cz>
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Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        Greg KH <gregkh@linuxfoundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
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From: Jiri Slaby <jslaby@suse.cz>
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Date: Fri, 26 Feb 2016 09:45:18 +0100
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On 02/26/2016, 01:38 AM, Peter Hurley wrote:
>> That would imply that RSP was off by +8 when the ttwu_stat() epilog was
>> executed so that RBP <= ret addr and RIP <= some local var in try_to_wake_up()
>> stack frame.
>>
>> Looks like R15 in the crash report could be what RBP should have been.
>>
>> Now to find out why RSP is +8
> 
> Which I would investigate if I could download that kernel.
> Unfortunately, OBS doesn't like me so if you could make that
> kernel available some other way or send me a mixed listing
> of kernel/sched/core.c

Actually I cannot do mixed listing using objdump, as my objdump
complains in the middle of vmlinux:
objdump: Dwarf Error: mangled line number section.

and dumps no more code afterwards. (And core.c is after the error happens.)

Nevertheless, I did:
gdb vmlinux-4.4.2-3-default -ex 'disass /m try_to_wake_up' --batch >
try_to_wake_up.mixed
gdb vmlinux-4.4.2-3-default -ex 'disass /m ttwu_stat' --batch
>ttwu_stat.mixed

And both will appear at:
http://labs.suse.cz/jslaby/bug-968218/

thanks,
-- 
js
suse labs