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From: Vivek Goyal <vgoyal@redhat.com>
To: Prarit Bhargava <prarit@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>,
	isimatu.yasuaki@jp.fujitsu.com, Andi Kleen <ak@linux.intel.com>,
	linux-doc@vger.kernel.org, linux-api@vger.kernel.org,
	Rusty Russell <rusty@rustcorp.com.au>,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	Fabian Frederick <fabf@skynet.be>,
	jbaron@akamai.com, "H. Peter Anvin" <hpa@zytor.com>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] kernel, add panic_on_warn
Date: Mon, 3 Nov 2014 10:18:37 -0500	[thread overview]
Message-ID: <20141103151837.GA22503@redhat.com> (raw)
In-Reply-To: <545783FA.4050508@redhat.com>

On Mon, Nov 03, 2014 at 08:32:42AM -0500, Prarit Bhargava wrote:
> 
> 
> On 10/30/2014 09:58 PM, Hedi Berriche wrote:
> > On Thu, Oct 30, 2014 at 17:06 Prarit Bhargava wrote:
> > | There have been several times where I have had to rebuild a kernel to
> > | cause a panic when hitting a WARN() in the code in order to get a crash
> > | dump from a system.  Sometimes this is easy to do, other times (such as
> > | in the case of a remote admin) it is not trivial to send new images to the
> > | user.
> > | 
> > | A much easier method would be a switch to change the WARN() over to a
> > | panic.  This makes debugging easier in that I can now test the actual
> > | image the WARN() was seen on and I do not have to engage in remote
> > | debugging.
> > 
> > Do we want to leave it to usersspace[1] to ensure panic_on_warn is out
> > of the way in when the kdump kernel boots? or would a self-contained
> > approach be more preferable i.e. test whether we're a kdump kernel
> > before bothering with panic_on_warn?
> 
> Hmm ... this is a good point.  Vivek, do you have a preference?  I'm willing to
> code it either way.  I should be able to put in a is_kdump_kernel() check
> without any problems but I'm not sure if that is the right thing to do here.
> 

I think it will make sense to modify user space scripts to get rid of
panic_on_warn for kdump kernel.

Thanks
Vivek

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WARNING: multiple messages have this Message-ID (diff)
From: Vivek Goyal <vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Prarit Bhargava <prarit-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Andi Kleen <ak-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>,
	Jonathan Corbet <corbet-T1hC0tSOHrs@public.gmane.org>,
	kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
	Rusty Russell <rusty-8n+1lVoiYb80n/F98K4Iww@public.gmane.org>,
	linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	jbaron-JqFfY2XvxFXQT0dZR+AlfA@public.gmane.org,
	Fabian Frederick <fabf-AgBVmzD5pcezQB+pC5nmwQ@public.gmane.org>,
	isimatu.yasuaki-+CUm20s59erQFUHtdCDX3A@public.gmane.org,
	"H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>,
	Masami Hiramatsu
	<masami.hiramatsu.pt-FCd8Q96Dh0JBDgjK7y7TUQ@public.gmane.org>,
	Andrew Morton
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH] kernel, add panic_on_warn
Date: Mon, 3 Nov 2014 10:18:37 -0500	[thread overview]
Message-ID: <20141103151837.GA22503@redhat.com> (raw)
In-Reply-To: <545783FA.4050508-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

On Mon, Nov 03, 2014 at 08:32:42AM -0500, Prarit Bhargava wrote:
> 
> 
> On 10/30/2014 09:58 PM, Hedi Berriche wrote:
> > On Thu, Oct 30, 2014 at 17:06 Prarit Bhargava wrote:
> > | There have been several times where I have had to rebuild a kernel to
> > | cause a panic when hitting a WARN() in the code in order to get a crash
> > | dump from a system.  Sometimes this is easy to do, other times (such as
> > | in the case of a remote admin) it is not trivial to send new images to the
> > | user.
> > | 
> > | A much easier method would be a switch to change the WARN() over to a
> > | panic.  This makes debugging easier in that I can now test the actual
> > | image the WARN() was seen on and I do not have to engage in remote
> > | debugging.
> > 
> > Do we want to leave it to usersspace[1] to ensure panic_on_warn is out
> > of the way in when the kdump kernel boots? or would a self-contained
> > approach be more preferable i.e. test whether we're a kdump kernel
> > before bothering with panic_on_warn?
> 
> Hmm ... this is a good point.  Vivek, do you have a preference?  I'm willing to
> code it either way.  I should be able to put in a is_kdump_kernel() check
> without any problems but I'm not sure if that is the right thing to do here.
> 

I think it will make sense to modify user space scripts to get rid of
panic_on_warn for kdump kernel.

Thanks
Vivek

WARNING: multiple messages have this Message-ID (diff)
From: Vivek Goyal <vgoyal@redhat.com>
To: Prarit Bhargava <prarit@redhat.com>
Cc: linux-kernel@vger.kernel.org, Andi Kleen <ak@linux.intel.com>,
	Jonathan Corbet <corbet@lwn.net>,
	kexec@lists.infradead.org, Rusty Russell <rusty@rustcorp.com.au>,
	linux-doc@vger.kernel.org, jbaron@akamai.com,
	Fabian Frederick <fabf@skynet.be>,
	isimatu.yasuaki@jp.fujitsu.com, "H. Peter Anvin" <hpa@zytor.com>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-api@vger.kernel.org
Subject: Re: [PATCH] kernel, add panic_on_warn
Date: Mon, 3 Nov 2014 10:18:37 -0500	[thread overview]
Message-ID: <20141103151837.GA22503@redhat.com> (raw)
In-Reply-To: <545783FA.4050508@redhat.com>

On Mon, Nov 03, 2014 at 08:32:42AM -0500, Prarit Bhargava wrote:
> 
> 
> On 10/30/2014 09:58 PM, Hedi Berriche wrote:
> > On Thu, Oct 30, 2014 at 17:06 Prarit Bhargava wrote:
> > | There have been several times where I have had to rebuild a kernel to
> > | cause a panic when hitting a WARN() in the code in order to get a crash
> > | dump from a system.  Sometimes this is easy to do, other times (such as
> > | in the case of a remote admin) it is not trivial to send new images to the
> > | user.
> > | 
> > | A much easier method would be a switch to change the WARN() over to a
> > | panic.  This makes debugging easier in that I can now test the actual
> > | image the WARN() was seen on and I do not have to engage in remote
> > | debugging.
> > 
> > Do we want to leave it to usersspace[1] to ensure panic_on_warn is out
> > of the way in when the kdump kernel boots? or would a self-contained
> > approach be more preferable i.e. test whether we're a kdump kernel
> > before bothering with panic_on_warn?
> 
> Hmm ... this is a good point.  Vivek, do you have a preference?  I'm willing to
> code it either way.  I should be able to put in a is_kdump_kernel() check
> without any problems but I'm not sure if that is the right thing to do here.
> 

I think it will make sense to modify user space scripts to get rid of
panic_on_warn for kdump kernel.

Thanks
Vivek

  reply	other threads:[~2014-11-03 15:19 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-30 17:03 [PATCH] kernel, add panic_on_warn Prarit Bhargava
2014-10-30 17:03 ` Prarit Bhargava
2014-10-30 17:24 ` H. Peter Anvin
2014-10-30 17:24   ` H. Peter Anvin
2014-10-30 17:24   ` H. Peter Anvin
2014-10-31  1:58 ` Hedi Berriche
2014-10-31  1:58   ` Hedi Berriche
2014-10-31  1:58   ` Hedi Berriche
2014-11-03 13:32   ` Prarit Bhargava
2014-11-03 13:32     ` Prarit Bhargava
2014-11-03 13:32     ` Prarit Bhargava
2014-11-03 15:18     ` Vivek Goyal [this message]
2014-11-03 15:18       ` Vivek Goyal
2014-11-03 15:18       ` Vivek Goyal
  -- strict thread matches above, loose matches on Subject: below --
2014-11-04 15:41 Prarit Bhargava
2014-11-04 15:41 ` Prarit Bhargava
2014-11-04 15:41 ` Prarit Bhargava
2014-11-05  4:27 ` WANG Chao
2014-11-05  4:27   ` WANG Chao
2014-11-05  4:55 ` Yasuaki Ishimatsu
2014-11-05  4:55   ` Yasuaki Ishimatsu
2014-11-05  4:55   ` Yasuaki Ishimatsu

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