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From: Dave Hansen <dave.hansen@linux•intel.com>
To: christophe leroy <christophe.leroy@c-s•fr>,
	Holger Brunck <holger.brunck@keymile•com>,
	"linuxppc-dev@lists•ozlabs.org" <linuxppc-dev@lists•ozlabs.org>
Cc: "mingo@kernel•org" <mingo@kernel•org>
Subject: Re: debug problems on ppc 83xx target due to changed struct task_struct
Date: Tue, 16 Aug 2016 10:36:15 -0700	[thread overview]
Message-ID: <57B34F0F.8080100@linux.intel.com> (raw)
In-Reply-To: <3f1dff88-cd24-b36e-da9a-e84627929975@c-s.fr>

On 08/16/2016 10:27 AM, christophe leroy wrote:
> If I debug a very small app, it gets stuck quickly after the app has
> stopped: indeed, the console seems ok but as soon as I try to execute
> something simple, like a ps or top, it get stuck. The target still
> responds to pings, but nothing else.

This one is a pretty common symptom when the kernel crashes holding a
per-process lock of some kind, probably most commonly mmap_sem.

Do you have a serial console?  Can you do a sysrq-t on it to get stack
dumps of the hung processes and ps?

It's time to turn on all the debugging options we can find.  Can you
build a kernel with all this stuff enabled (=y on all of these):

CONFIG_SLUB_DEBUG
CONFIG_DEBUG_VM
CONFIG_DEBUG_PAGEALLOC
CONFIG_PAGE_POISONING
CONFIG_SLUB_DEBUG_ON
CONFIG_KASAN
CONFIG_*LOCKUP_DETECTOR
CONFIG_DETECT_HUNG_TASK
CONFIG_SCHED_DEBUG
CONFIG_DEBUG_PREEMPT
CONFIG_MAGIC_SYSRQ

And all of the spinlock/lockdep stuff enabled too:

CONFIG_DEBUG_SPINLOCK=y
CONFIG_DEBUG_MUTEXES=y
CONFIG_DEBUG_LOCK_ALLOC=y
CONFIG_PROVE_LOCKING=y
CONFIG_LOCKDEP=y
CONFIG_DEBUG_ATOMIC_SLEEP=y
CONFIG_STACKTRACE=y
CONFIG_DEBUG_LIST=y

Let's hope that these turn something up.

  reply	other threads:[~2016-08-16 17:36 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
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 [this message]
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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