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[PATCH] i386 - Fix regression, endless loop in ptrace singlestep over an int80

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From: Jason Wessel <jason.wessel@...>
To: lkml <linux-kernel@...>, <stable@...>
Subject: [PATCH] i386 - Fix regression, endless loop in ptrace singlestep over an int80
Date: Monday, July 2, 2007 - 4:53 pm

Attached is a patch with a complete test case to fix the regression 
introduced by the commit: 635cf99a80f4ebee59d70eb64bb85ce829e4591f.

This patch is against kernel 2.6.21 but the fix is applicable to 2.6.21 
and up.  Prior to the commit that introduced the regression the ltp 
ptrace tests would complete correctly.  I augmented the test case from 
the original patch header to include the problem case that shows up in 
the lpt tests.

The brief summary is that the the TIF_SINGLESTEP state needs to be 
altered on the exit path and not the entry path to a syscall, else it 
can loop forever on the same instruction right after the syscall is 
executed in certain cases.

Thanks,
Jason.
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Messages in current thread:
[PATCH] i386 - Fix regression, endless loop in ptrace single..., Jason Wessel, (Mon Jul 2, 4:53 pm)
Re: [PATCH] i386 - Fix regression, endless loop in ptrace si..., Chuck Ebbert, (Mon Jul 2, 6:03 pm)
Re: [PATCH] i386 - Fix regression, endless loop in ptrace si..., Jason Wessel, (Mon Jul 2, 6:20 pm)
Re: [PATCH] i386 - Fix regression, endless loop in ptrace si..., Jeremy Fitzhardinge, (Mon Jul 2, 5:07 pm)