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From: Stefan Weil <weil@mail.berlios.de>
To: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] Re: SIGSEGV on Windows with KQEMU enabled
Date: Sun, 15 Mar 2009 17:16:50 +0100	[thread overview]
Message-ID: <49BD29F2.9000400@mail.berlios.de> (raw)
In-Reply-To: <200903150042.58341.paul@codesourcery.com>

Paul Brook schrieb:
>>> But really funny think is the change that triggers the bug is precisely
>>> this: -Monitor *cur_mon;
>>> +Monitor *cur_mon = NULL;
>>>
>>> Obviously, kqemu is happier having garbage in the cur_mon than NULL
>>>       
>> I rather expect that to _hide_ the bug.  The "garbage" might be a
>> left-over from the heap.
>>     
>
> This change does precisely nothing. In C all global and static variables are 
> implicitly zero initialized.
>
> Paul
>
>
>   

This change changes the location of variable cur_mon from BSS to DATA
segment.
For buggy code, such changes surely can have an effect. Maybe some other
variable in data which is located before cur_mon destroys cur_mon.

Running in gdb with a hardware watchpoint on any change of cur_mon might
help
to see if cur_mon is overwritten.

Stefan

  reply	other threads:[~2009-03-15 16:17 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-03-07  0:39 [Qemu-devel] SIGSEGV on Windows with KQEMU enabled Consul
2009-03-07  2:51 ` Anthony Liguori
2009-03-13  1:28   ` [Qemu-devel] " Consul
2009-03-13 10:37     ` Johannes Schindelin
2009-03-13 17:33       ` Consul
2009-03-14 12:16         ` Johannes Schindelin
2009-03-14 12:36           ` Andreas Färber
2009-03-15  0:42           ` Paul Brook
2009-03-15 16:16             ` Stefan Weil [this message]
2009-03-15 16:39               ` Avi Kivity
2009-03-16 10:22             ` Johannes Schindelin

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