From: "H. Peter Anvin" <hpa@zytor.com>
To: Prarit Bhargava <prarit@redhat.com>, linux-kernel@vger.kernel.org
Cc: 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, linux-api@vger.kernel.org,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
Andrew Morton <akpm@linux-foundation.org>,
vgoyal@redhat.com
Subject: Re: [PATCH] kernel, add panic_on_warn
Date: Thu, 30 Oct 2014 10:24:19 -0700 [thread overview]
Message-ID: <54527443.6030007@zytor.com> (raw)
In-Reply-To: <1414688627-5298-1-git-send-email-prarit@redhat.com>
On 10/30/2014 10:03 AM, 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.
>
> This patch adds a panic_on_warn kernel parameter and
> /proc/sys/kernel/panic_on_warn calls panic() in the warn_slowpath_common()
> path. The function will still print out the location of the warning.
>
> An example of the panic_on_warn output:
>
> The first line below is from the WARN_ON() to output the WARN_ON()'s location.
> After that the panic() output is displayed.
>
There is another very valid use for this: many operators would rather a
machine shuts down than being potentially compromised either
functionally or security-wise.
-hpa
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WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>
To: Prarit Bhargava <prarit-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: 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,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Masami Hiramatsu
<masami.hiramatsu.pt-FCd8Q96Dh0JBDgjK7y7TUQ@public.gmane.org>,
Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org
Subject: Re: [PATCH] kernel, add panic_on_warn
Date: Thu, 30 Oct 2014 10:24:19 -0700 [thread overview]
Message-ID: <54527443.6030007@zytor.com> (raw)
In-Reply-To: <1414688627-5298-1-git-send-email-prarit-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
On 10/30/2014 10:03 AM, 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.
>
> This patch adds a panic_on_warn kernel parameter and
> /proc/sys/kernel/panic_on_warn calls panic() in the warn_slowpath_common()
> path. The function will still print out the location of the warning.
>
> An example of the panic_on_warn output:
>
> The first line below is from the WARN_ON() to output the WARN_ON()'s location.
> After that the panic() output is displayed.
>
There is another very valid use for this: many operators would rather a
machine shuts down than being potentially compromised either
functionally or security-wise.
-hpa
WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: Prarit Bhargava <prarit@redhat.com>, linux-kernel@vger.kernel.org
Cc: Jonathan Corbet <corbet@lwn.net>,
Andrew Morton <akpm@linux-foundation.org>,
Rusty Russell <rusty@rustcorp.com.au>,
Andi Kleen <ak@linux.intel.com>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
Fabian Frederick <fabf@skynet.be>,
vgoyal@redhat.com, isimatu.yasuaki@jp.fujitsu.com,
jbaron@akamai.com, linux-doc@vger.kernel.org,
kexec@lists.infradead.org, linux-api@vger.kernel.org
Subject: Re: [PATCH] kernel, add panic_on_warn
Date: Thu, 30 Oct 2014 10:24:19 -0700 [thread overview]
Message-ID: <54527443.6030007@zytor.com> (raw)
In-Reply-To: <1414688627-5298-1-git-send-email-prarit@redhat.com>
On 10/30/2014 10:03 AM, 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.
>
> This patch adds a panic_on_warn kernel parameter and
> /proc/sys/kernel/panic_on_warn calls panic() in the warn_slowpath_common()
> path. The function will still print out the location of the warning.
>
> An example of the panic_on_warn output:
>
> The first line below is from the WARN_ON() to output the WARN_ON()'s location.
> After that the panic() output is displayed.
>
There is another very valid use for this: many operators would rather a
machine shuts down than being potentially compromised either
functionally or security-wise.
-hpa
next prev parent reply other threads:[~2014-10-30 17:25 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 [this message]
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
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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