perf/x86/intel: Fix LBR callstack issue caused by FREEZE_LBRS_ON_PMI
This patch fixes an issue which introduced by commit 1a78d937 ("perf/x86/intel: Streamline LBR MSR handling in PMI"). The old patch not only avoids writing LBR_SELECT MSR in PMI, but also avoids updating lbr_select variable. So in PMI, FREEZE_LBRS_ON_PMI bit is always mistakenly set for IA32_DEBUGCTLMSR MSR, which causes superfluous increase/decrease of LBR_TOS when collecting LBR callstack. Reported-by: Milian Wolff <mail@milianw.de> Signed-off-by: Kan Liang <kan.liang@intel.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: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/1439815051-8616-1-git-send-email-kan.liang@intel.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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