perf/x86: Fix LBR related crashes on Intel Atom
authorStephane Eranian <eranian@google.com>
Thu, 3 Dec 2015 22:33:17 +0000 (23:33 +0100)
committerIngo Molnar <mingo@kernel.org>
Wed, 6 Jan 2016 10:15:33 +0000 (11:15 +0100)
commit6fc2e83077b05a061afe9b24f2fdff7a0434eb67
tree6445f7732002cfef833745d612f0d05f300a9b35
parent61b87cae6361ea6af161c1ffa549898892707b19
perf/x86: Fix LBR related crashes on Intel Atom

This patches fixes the LBR kernel crashes on Intel Atom.

The kernel was assuming that if the CPU supports 64-bit format
LBR, then it has an LBR_SELECT MSR. Atom uses 64-bit LBR format
but does not have LBR_SELECT. That was causing NULL pointer
dereferences in a couple of places.

Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: kan.liang@intel.com
Fixes: 96f3eda67fcf ("perf/x86/intel: Fix static checker warning in lbr enable")
Link: http://lkml.kernel.org/r/1449182000-31524-2-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/x86/kernel/cpu/perf_event_intel_lbr.c