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From: "Jan Beulich" <jbeulich@novell.com>
To: "Jeremy Fitzhardinge" <jeremy@goop.org>
Cc: "Ingo Molnar" <mingo@elte.hu>,
	"the arch/x86 maintainers" <x86@kernel.org>,
	"Linus Torvalds" <torvalds@linux-foundation.org>,
	"Xen-devel" <xen-devel@lists.xensource.com>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
Subject: Re: [Xen-devel] [PATCH 2/5] xen/x86-64: clean up warnings	 aboutIST-usingtraps
Date: Fri, 08 May 2009 16:30:39 +0100	[thread overview]
Message-ID: <4A046C3F.76EA.0078.0@novell.com> (raw)
In-Reply-To: <4A044E55.20803@goop.org>

>>> Jeremy Fitzhardinge <jeremy@goop.org> 08.05.09 17:23 >>>
>Jan Beulich wrote:
>>> else if (addr == (unsigned long)int3)
>>> 		addr = (unsigned long)xen_int3;
>>> -	else
>>> -		WARN_ON(val->ist != 0);
>>> +	else if (addr == (unsigned long)double_fault ||
>>> +		 addr == (unsigned long)stack_segment) {
>>>     
>>
>> I don't think you want to exclude handling stack faults: Ordinary memory
>> references using rsp or rbp as the base register will cause these instead
>> of general protection faults when the resulting effective address is non-
>> canonical.
>>   
>
>So even usermode memory accesses?  Ew.

Yes, just try it out - you'll observe them generate SIGBUS instead of SIGSEGV.

Jan


      reply	other threads:[~2009-05-08 15:30 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-07 18:56 [PATCH 2/5] xen/x86-64: clean up warnings about IST-using traps Jeremy Fitzhardinge
2009-05-08  7:20 ` [Xen-devel] [PATCH 2/5] xen/x86-64: clean up warnings aboutIST-using traps Jan Beulich
2009-05-08  8:58   ` Ingo Molnar
2009-05-08 15:31     ` Jeremy Fitzhardinge
2009-05-08 15:23   ` Jeremy Fitzhardinge
2009-05-08 15:30     ` Jan Beulich [this message]

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