From: Valdis.Kletnieks@vt.edu
To: Roland McGrath <roland@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH x86/mm] x86_64 save_i387_ia32 snafu
Date: Sat, 12 Jan 2008 00:51:58 -0500 [thread overview]
Message-ID: <5212.1200117118@turing-police.cc.vt.edu> (raw)
In-Reply-To: Your message of "Fri, 11 Jan 2008 13:31:47 PST." <20080111213147.EBE0C26F9A9@magilla.localdomain>
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On Fri, 11 Jan 2008 13:31:47 PST, Roland McGrath said:
> > thanks, applied. Does this explain the crash/hang problems with 32-bit
> > apps on 64-bit kernels? What was the exact failure mode?
>
> It does. Any 32-bit process trying to run a signal handler when it had
> used the FPU, would clobber "current" with FP bits. The observed failure
> mode was shortly after this in the signal handler setup code, when it
> crashed due to current->mm being zero (current->pid also being zero, and
> the whole first 512 bytes of the task_struct being garbage).
For what it's worth, this patch fixes a problem I had in 24-rc6-mm1 with
kernel panics when certain X programs exited (Eterm being the biggest cause),
that I had bisected to "somewhere in git-x86.patch"....
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next prev parent reply other threads:[~2008-01-12 5:52 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4786A9CA.2090008@zytor.com>
[not found] ` <20080111004422.2B3F926F9A6@magilla.localdomain>
[not found] ` <4786BE15.6040604@zytor.com>
[not found] ` <20080111024929.37FDB26F9A9@magilla.localdomain>
[not found] ` <4786DB3B.8070808@zytor.com>
2008-01-11 10:43 ` [PATCH x86/mm] x86_64 save_i387_ia32 snafu Roland McGrath
2008-01-11 10:49 ` Ingo Molnar
2008-01-11 21:31 ` Roland McGrath
2008-01-12 5:51 ` Valdis.Kletnieks [this message]
2008-01-12 6:59 ` Ingo Molnar
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