linux-kernel - RE: Oops with tip/x86/fpu

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Date:	Thu, 26 Mar 2015 22:48:18 +0000
From:	"Yu, Fenghua" <fenghua.yu@...el.com>
To:	"Hansen, Dave" <dave.hansen@...el.com>,
	Oleg Nesterov <oleg@...hat.com>, Borislav Petkov <bp@...e.de>
CC:	Quentin Casasnovas <quentin.casasnovas@...cle.com>,
	Andy Lutomirski <luto@...capital.net>,
	Ingo Molnar <mingo@...nel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Pekka Riikonen <priikone@....fi>,
	"Rik van Riel" <riel@...hat.com>,
	Suresh Siddha <sbsiddha@...il.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: RE: Oops with tip/x86/fpu

> From: Hansen, Dave
> Sent: Thursday, March 26, 2015 3:44 PM
> On 03/26/2015 03:37 PM, Yu, Fenghua wrote:
> >> > void sighup(int sig, siginfo_t *info, void *ctxt) {
> >> > 	struct ucontext *uctxt = ctxt;
> >> > 	struct sigcontext *sctxt = (void*)&uctxt->uc_mcontext;
> >> >
> >> > 	printf("SIGHUP! %p\n", sctxt->fpstate);
> >> > 	sctxt->fpstate = (void *)1;
> > sctxt->fpstate=(void *)1 changes the fpstate pointer in the sigcontext. It
> will generate segfault and bad frame info in kernel.
> >
> > This is expected behavior, right? Is this still a valid test?
> 
> Just to be clear, I saw a full-on kernel panic induced from an unprivileged
> application.
> 
> Are you seeing something different?

I use latest tip tree. Maybe it has the fixes already. I see "bad frame" reported in kernel. Seems the issue has been fixed in tip tree.

Thanks.

-Fenghua
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