Techwizz/kernel-fxtec-pro1x
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

x86/signals: Clear RF EFLAGS bit for signal handler

Browse source 
Clearing RF EFLAGS bit for signal handler. The reason is
that this flag is set by debug exception code to prevent
the recursive exception entry.

Leaving it set for signal handler might prevent debug
exception of the signal handler itself.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Originally-Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Stephane Eranian <eranian@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1367421944-19082-3-git-send-email-jolsa@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Jiri Olsa 2013-05-01 17:25:42 +02:00 committed by Ingo Molnar
parent 5e219b3c67
commit 24cda10996
1 changed files with 6 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
arch/x86/kernel/signal.c
View file

@ -664,6 +664,12 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs)
* Clear the direction flag as per the ABI for function entry.
*/
regs->flags &= ~X86_EFLAGS_DF;
/*
* Clear RF when entering the signal handler, because
* it might disable possible debug exception from the
* signal handler.
*/
regs->flags &= ~X86_EFLAGS_RF;
/*
* Clear TF when entering the signal handler, but
* notify any tracer that was single-stepping it.