On Thu, Nov 26, 2020 at 08:09:21PM +0900, Namhyung Kim wrote:
> The commit 3966c3feca3f ("x86/perf/amd: Remove need to check "running"
> bit in NMI handler") introduced this. It seems x86_pmu_stop can be
> called recursively (like when it losts some samples) like below:
>
> x86_pmu_stop
> intel_pmu_disable_event (x86_pmu_disable)
> intel_pmu_pebs_disable
> intel_pmu_drain_pebs_nhm (x86_pmu_drain_pebs_buffer)
> x86_pmu_stop
>
> While commit 35d1ce6bec13 ("perf/x86/intel/ds: Fix x86_pmu_stop
> warning for large PEBS") fixed it for the normal cases, there's
> another path to call x86_pmu_stop() recursively when a PEBS error was
> detected (like two or more counters overflowed at the same time).
>
> Like in the Kan's previous fix, we can skip the interrupt accounting
> for large PEBS, so check the iregs which is set for PMI only.
>
> Fixes: 3966c3feca3f ("x86/perf/amd: Remove need to check "running" bit in NMI
> handler")
> Reported-by: John Sperbeck <[email protected]>
> Suggested-by: Peter Zijlstra <[email protected]>
> Cc: "Lendacky, Thomas" <[email protected]>
> Cc: Kan Liang <[email protected]>
> Signed-off-by: Namhyung Kim <[email protected]>
Thanks for both!
