linux/arch/x86/events
Alexander Shishkin 92ca7da4bd perf/x86/intel: Fix PT PMI handling
Commit:

  ccbebba4c6 ("perf/x86/intel/pt: Bypass PT vs. LBR exclusivity if the core supports it")

skips the PT/LBR exclusivity check on CPUs where PT and LBRs coexist, but
also inadvertently skips the active_events bump for PT in that case, which
is a bug. If there aren't any hardware events at the same time as PT, the
PMI handler will ignore PT PMIs, as active_events reads zero in that case,
resulting in the "Uhhuh" spurious NMI warning and PT data loss.

Fix this by always increasing active_events for PT events.

Fixes: ccbebba4c6 ("perf/x86/intel/pt: Bypass PT vs. LBR exclusivity if the core supports it")
Reported-by: Vitaly Slobodskoy <vitaly.slobodskoy@intel.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Link: https://lkml.kernel.org/r/20191210105101.77210-1-alexander.shishkin@linux.intel.com
2019-12-17 13:32:46 +01:00
..
amd perf/x86/amd: Remove set but not used variable 'active' 2019-11-11 08:31:55 +01:00
intel perf/x86/intel/bts: Fix the use of page_private() 2019-12-17 13:32:46 +01:00
core.c perf/x86/intel: Fix PT PMI handling 2019-12-17 13:32:46 +01:00
Kconfig License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Makefile perf/x86: Add MSR probe interface 2019-06-24 19:28:31 +02:00
msr.c perf/x86/msr: Add Tiger Lake CPU support 2019-10-12 15:13:09 +02:00
perf_event.h perf/x86/intel: Implement LBR callstack context synchronization 2019-10-28 12:51:01 +01:00
probe.c perf/x86: Add MSR probe interface 2019-06-24 19:28:31 +02:00
probe.h perf/x86: Add MSR probe interface 2019-06-24 19:28:31 +02:00