On 01/16/2014 08:39 AM, tip-bot for Peter Zijlstra wrote:
Commit-ID:  c026b3591e4f2a4993df773183704bb31634e0bd
Gitweb:     http://git.kernel.org/tip/c026b3591e4f2a4993df773183704bb31634e0bd
Author:     Peter Zijlstra<[email protected]>
AuthorDate: Fri, 10 Jan 2014 21:06:03 +0100
Committer:  Ingo Molnar<[email protected]>
CommitDate: Thu, 16 Jan 2014 09:19:48 +0100

x86, mm, perf: Allow recursive faults from interrupts

Waiman managed to trigger a PMI while in a emulate_vsyscall() fault,
the PMI in turn managed to trigger a fault while obtaining a stack
trace. This triggered the sig_on_uaccess_error recursive fault logic
and killed the process dead.

Fix this by explicitly excluding interrupts from the recursive fault
logic.

Reported-and-Tested-by: Waiman Long<[email protected]>
Fixes: e00b12e64be9 ("perf/x86: Further optimize copy_from_user_nmi()")
Cc: Aswin Chandramouleeswaran<[email protected]>
Cc: Scott J Norton<[email protected]>
Cc: Linus Torvalds<[email protected]>
Cc: Andy Lutomirski<[email protected]>
Cc: Arnaldo Carvalho de Melo<[email protected]>
Cc: Andrew Morton<[email protected]>
Signed-off-by: Peter Zijlstra<[email protected]>
Link: 
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar<[email protected]>
---
  arch/x86/mm/fault.c | 18 ++++++++++++++++++
  1 file changed, 18 insertions(+)



Will that be picked up by Linus as it is a 3.13 regression?

-Longman
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