diff options
| author | Jiri Olsa <jolsa@redhat.com> | 2016-10-20 13:10:11 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-10-28 11:06:25 +0200 |
| commit | 0933840acf7b65d6d30a5b6089d882afea57aca3 (patch) | |
| tree | d70660c9cc59695decc9860a0446d4dd476feeac /kernel/kcov.c | |
| parent | perf/x86/intel/cstate: Add C-state residency events for Knights Landing (diff) | |
| download | linux-0933840acf7b65d6d30a5b6089d882afea57aca3.tar.xz linux-0933840acf7b65d6d30a5b6089d882afea57aca3.zip | |
perf/core: Protect PMU device removal with a 'pmu_bus_running' check, to fix CONFIG_DEBUG_TEST_DRIVER_REMOVE=y kernel panic
CAI Qian reported a crash in the PMU uncore device removal code,
enabled by the CONFIG_DEBUG_TEST_DRIVER_REMOVE=y option:
https://marc.info/?l=linux-kernel&m=147688837328451
The reason for the crash is that perf_pmu_unregister() tries to remove
a PMU device which is not added at this point. We add PMU devices
only after pmu_bus is registered, which happens in the
perf_event_sysfs_init() call and sets the 'pmu_bus_running' flag.
The fix is to get the 'pmu_bus_running' flag state at the point
the PMU is taken out of the PMU list and remove the device
later only if it's set.
Reported-by: CAI Qian <caiqian@redhat.com>
Tested-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20161020111011.GA13361@krava
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/kcov.c')
0 files changed, 0 insertions, 0 deletions