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From: Dave Hansen <dave.hansen@linux•intel.com>
To: Holger Brunck <holger.brunck@keymile•com>, linuxppc-dev@lists•ozlabs.org
Cc: mingo@kernel•org
Subject: Re: debug problems on ppc 83xx target due to changed struct task_struct
Date: Fri, 12 Aug 2016 08:14:46 -0700	[thread overview]
Message-ID: <57ADE7E6.9030900@linux.intel.com> (raw)
In-Reply-To: <dc38afe9-6b78-f3f5-666b-986939e40fc6@keymile.com>

On 08/12/2016 07:50 AM, Holger Brunck wrote:
> When I try to debug our multithreaded userspace application with gdb I  get
> stuck when trying to single step code.

Can you clarify "stuck"?  Like the instructions don't advance?  Have you
been able to find a root cause for this?

> Does anyone have an idea why the change in sched.h break my debug
> usecase? Anyone out here who is debugging ppc83xx targets flawlessly
> with a recent kernel?

Thanks for going to the trouble of bisecting this, btw!

I'd _suspect_ something very specific to your platform since this
doesn't appear to affect even other ppc variants.

I wonder if making it cross a page boundary from some other structure
causes this, or moving it relative to something else.  Could you try
moving it to a few more places, or padding it by, say PAGE_SIZE on
either side makes a difference?

Is there some assembly involved in your single-stepping, or some other
code that assumes relative offsets between two pieces of 'task_struct'?

  reply	other threads:[~2016-08-12 15:14 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-08-12 14:50 debug problems on ppc 83xx target due to changed struct task_struct Holger Brunck
2016-08-12 15:14 ` Dave Hansen [this message]
2016-08-12 15:47   ` Holger Brunck
2016-08-12 16:09     ` Dave Hansen
2016-08-15 14:35       ` Holger Brunck
2016-08-15 16:19         ` Dave Hansen
2016-08-16 17:27           ` christophe leroy
2016-08-16 17:36             ` Dave Hansen
2016-08-17  8:22               ` Christophe Leroy
2016-08-17 15:27             ` Holger Brunck
2016-08-18  8:23               ` Christophe Leroy
2016-08-19 11:03               ` Christophe Leroy
2016-08-19 11:14                 ` Holger Brunck
2016-08-19 13:44                   ` Christophe Leroy
2016-08-19 16:26                     ` Holger Brunck
2016-08-16 22:13           ` Benjamin Herrenschmidt
2016-08-17 15:05             ` Holger Brunck
2016-08-17 14:59           ` Holger Brunck

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