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From: Prarit Bhargava <prarit@redhat.com>
To: David Rientjes <rientjes@google.com>
Cc: Vivek Goyal <vgoyal@redhat.com>,
	linux-kernel@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
	Andrew Morton <akpm@linux-foundation.org>,
	Rusty Russell <rusty@rustcorp.com.au>,
	"H. Peter Anvin" <hpa@zytor.com>, Andi Kleen <ak@linux.intel.com>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
	Fabian Frederick <fabf@skynet.be>,
	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 v8] kernel, add panic_on_warn
Date: Sat, 08 Nov 2014 08:29:21 -0500	[thread overview]
Message-ID: <545E1AB1.9030001@redhat.com> (raw)
In-Reply-To: <alpine.DEB.2.10.1411071306370.12192@chino.kir.corp.google.com>



On 11/07/2014 04:09 PM, David Rientjes wrote:
> On Fri, 7 Nov 2014, Prarit Bhargava wrote:
> 
>> There very much is.  Consider a thread that hits a WARN() and then panics.  Then
>> somewhere in the panic code the thread hits another WARN() ... and then panics
>> again.  Previously this would have caused the system to "finish" panick'ing.
>> Now it makes the system hang.
>>
> 
> Then we're back to square one which is what is obviously the intent of 
> your patch and the comment that goes along with it: 

My original reply pointed out that the comment was wrong.

we want to clear
> panic_on_warn once and not allow multiple panic().  

On _this_ thread.  The multiple panic across threads cannot occur.

So why not just add
> the necessary synchronization to make sure that happens when WARN() 
> happens on two cpus simultaneously?

See above.

P.

> 

  reply	other threads:[~2014-11-08 13:30 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-05 11:42 [PATCH v8] kernel, add panic_on_warn Prarit Bhargava
2014-11-05 21:59 ` David Rientjes
2014-11-06 13:10   ` Prarit Bhargava
2014-11-06 21:57     ` David Rientjes
2014-11-06 22:07       ` Vivek Goyal
2014-11-06 22:52         ` Prarit Bhargava
2014-11-07 10:15         ` David Rientjes
2014-11-07 11:05           ` Prarit Bhargava
2014-11-07 21:09             ` David Rientjes
2014-11-08 13:29               ` Prarit Bhargava [this message]
2014-11-06 22:51       ` Prarit Bhargava

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