Messages in this thread | ![/](/images/icornerl.gif) | | Date | Fri, 17 May 2024 13:16:16 +0100 | Subject | Re: [PATCH] perf/arm-dmc620: Fix lockdep assert in ->event_init() | From | Robin Murphy <> |
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On 17/05/2024 1:02 pm, Will Deacon wrote: > On Tue, May 14, 2024 at 11:00:50AM -0700, Namhyung Kim wrote: >> for_each_sibling_event() checks leader's ctx but it doesn't have the ctx >> yet if it's the leader. Like in perf_event_validate_size(), we should >> skip checking siblings in that case. >> >> Fixes: f3c0eba287049 ("perf: Add a few assertions") >> Reported-by: Greg Thelen <gthelen@google.com> >> Cc: Robin Murphy <robin.murphy@arm.com> >> Cc: Tuan Phan <tuanphan@os.amperecomputing.com> >> Signed-off-by: Namhyung Kim <namhyung@kernel.org> >> --- >> drivers/perf/arm_dmc620_pmu.c | 9 ++++++--- >> 1 file changed, 6 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/perf/arm_dmc620_pmu.c b/drivers/perf/arm_dmc620_pmu.c >> index 8a81be2dd5ec..88c17c1d6d49 100644 >> --- a/drivers/perf/arm_dmc620_pmu.c >> +++ b/drivers/perf/arm_dmc620_pmu.c >> @@ -542,12 +542,16 @@ static int dmc620_pmu_event_init(struct perf_event *event) >> if (event->cpu < 0) >> return -EINVAL; >> >> + hwc->idx = -1; >> + >> + if (event->group_leader == event) >> + return 0; >> + >> /* >> * We can't atomically disable all HW counters so only one event allowed, >> * although software events are acceptable. >> */ >> - if (event->group_leader != event && >> - !is_software_event(event->group_leader)) >> + if (!is_software_event(event->group_leader)) >> return -EINVAL;
Oh, come to think of it, I believe we shouldn't actually need to keep this check either, since commit bf480f938566 ("perf/core: Don't allow grouping events from different hw pmus").
Thanks, Robin.
>> >> for_each_sibling_event(sibling, event->group_leader) { >> @@ -556,7 +560,6 @@ static int dmc620_pmu_event_init(struct perf_event *event) >> return -EINVAL; >> } >> >> - hwc->idx = -1; >> return 0; >> } > > Thanks, I'll pick this up, although Mark reckoned he'd found some other > issues over at: > > https://lore.kernel.org/r/Zg0l642PgQ7T3a8Z@FVFF77S0Q05N > > but didn't elaborate on what exactly he'd found :/ > > Will > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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