5e219b3c67
While porting Vince's perf overflow tests I found perf event breakpoint overflow does not work properly. I found the x86 RF EFLAG bit not being set when returning from debug exception after triggering signal handler. Which is exactly what you get when you set perf breakpoint overflow SIGIO handler. This patch and the next two patches fix the underlying bugs. This patch adds the RF EFLAGS bit to be restored on return from signal from the original register context before the signal was entered. This will prevent the RF flag to disappear when returning from exception due to the signal handler being executed. 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/1367421944-19082-2-git-send-email-jolsa@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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