Re: [tip:perf/core] x86, mm, perf: Allow recursive faults from interrupts

[Waiman Long]

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<peterz@xxxxxxxxxxxxx>
> AuthorDate: Fri, 10 Jan 2014 21:06:03 +0100
> Committer:  Ingo Molnar<mingo@xxxxxxxxxx>
> 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<waiman.long@xxxxxx>
> Fixes: e00b12e64be9 ("perf/x86: Further optimize copy_from_user_nmi()")
> Cc: Aswin Chandramouleeswaran<aswin@xxxxxx>
> Cc: Scott J Norton<scott.norton@xxxxxx>
> Cc: Linus Torvalds<torvalds@xxxxxxxxxxxxxxxxxxxx>
> Cc: Andy Lutomirski<luto@xxxxxxxxxxxxxx>
> Cc: Arnaldo Carvalho de Melo<acme@xxxxxxxxxxxxxxxxxx>
> Cc: Andrew Morton<akpm@xxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Peter Zijlstra<peterz@xxxxxxxxxxxxx>
> Link: http://lkml.kernel.org/r/20140110200603.GJ7572@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Ingo Molnar<mingo@xxxxxxxxxx>
> ---
>   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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