[Devel] [PATCH rh7] x86, mm, perf: Allow recursive faults from interrupts

[Andrey Ryabinin]

On 1/24/19 6:44 PM, Andrey Ryabinin wrote:
> From: Peter Zijlstra <peterz at infradead.org>
> 
> 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 at hp.com>
> Fixes: e00b12e64be9 ("perf/x86: Further optimize copy_from_user_nmi()")
> Cc: Aswin Chandramouleeswaran <aswin at hp.com>
> Cc: Scott J Norton <scott.norton at hp.com>
> Cc: Linus Torvalds <torvalds at linux-foundation.org>
> Cc: Andy Lutomirski <luto at amacapital.net>
> Cc: Arnaldo Carvalho de Melo <acme at ghostprotocols.net>
> Cc: Andrew Morton <akpm at linux-foundation.org>
> Signed-off-by: Peter Zijlstra <peterz at infradead.org>
> Link: http://lkml.kernel.org/r/20140110200603.GJ7572@laptop.programming.kicks-ass.net
> Signed-off-by: Ingo Molnar <mingo at kernel.org>

https://jira.sw.ru/browse/PSBM-91181

> (cherry picked from commit c026b3591e4f2a4993df773183704bb31634e0bd)
> Signed-off-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
> ---