WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] Re: [PATCH 2 of 4] xentrace: replace ASSERT with printk

To: George Dunlap <george.dunlap@xxxxxxxxxx>, Olaf Hering <olaf@xxxxxxxxx>
Subject: Re: [Xen-devel] Re: [PATCH 2 of 4] xentrace: replace ASSERT with printk in __trace_var
From: Keir Fraser <keir@xxxxxxx>
Date: Sat, 16 Jul 2011 09:20:54 +0100
Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Sat, 16 Jul 2011 01:22:31 -0700
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=sender:user-agent:date:subject:from:to:cc:message-id:thread-topic :thread-index:in-reply-to:mime-version:content-type :content-transfer-encoding; bh=o5ovuPSRTtMGcLacKnU2x0DaIyvzKit1o2tiL1SK4D4=; b=MlJNSafawEaNKLwgkQdr35ITzyoLt1fRJ4gqK6mR0sfZDIKCzwReiyjNcqgiu3Wo0E mfPcnCOJP6M+E2zz4TIuTW6F85oXKf6/Zztapmk3IyGmrVaOQmf25lOua8CvITPkpYt9 FJVoB4iuo45pHeaBalyWr16ZatAKPP6m7NyTs=
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <1310747494.448.95.camel@elijah>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcxDkUfARlLfMK2bx0+Dnq89a+qnug==
Thread-topic: [Xen-devel] Re: [PATCH 2 of 4] xentrace: replace ASSERT with printk in __trace_var
User-agent: Microsoft-Entourage/12.29.0.110113
It's not like we have dodgy third-party drivers to worry about. Just fix the
code -- *which is in the tree!* -- that is making the bad calls! It was
correct to make this an assert/bug_on in the first place.

 -- Keir

On 15/07/2011 17:31, "George Dunlap" <george.dunlap@xxxxxxxxxx> wrote:

> This seems likely to spam the console if there is a trace which violates
> this; and this may happen in production environments if the loglevel is
> increased.  I think putting in something to warn just once would be a
> better idea.
> 
>  -George
> 
> On Fri, 2011-07-15 at 16:38 +0100, Olaf Hering wrote:
>> # HG changeset patch
>> # User Olaf Hering <olaf@xxxxxxxxx>
>> # Date 1310741871 -7200
>> # Node ID e0ff4eea0432e0af3210e090a47414a0126e9904
>> # Parent  d0dcdddf5285eba0605a95dfda79b794803fa733
>> xentrace: replace ASSERT with printk in __trace_var
>> 
>> If trace_var gets called with large extra_data, do not crash the hypervisor.
>> Instead print a warning and truncate the buffer.
>> 
>> Signed-off-by: Olaf Hering <olaf@xxxxxxxxx>
>> 
>> diff -r d0dcdddf5285 -r e0ff4eea0432 xen/common/trace.c
>> --- a/xen/common/trace.c
>> +++ b/xen/common/trace.c
>> @@ -683,7 +683,10 @@ void __trace_var(u32 event, bool_t cycle
>>      if ( (extra % sizeof(u32)) != 0 )
>>          extra_word++;
>>      
>> -    ASSERT(extra_word <= TRACE_EXTRA_MAX);
>> +    if ( unlikely(extra_word > TRACE_EXTRA_MAX) )
>> +        printk(XENLOG_WARNING "xentrace: event %x extra_data %u too
>> large.\n",
>> +                event, extra);
>> +
>>      extra_word = min_t(int, extra_word, TRACE_EXTRA_MAX);
>>  
>>      /* Round size up to nearest word */
> 
> 
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>