If the PMU is used for AUX data sampling, the hardware event that triggers it may come in during a critical section of address filters adjustment (if it's delivered as NMI) and in turn call the address filter sync code, causing a spinlock recursion.
To prevent this, disable the PMU around these critical sections, so that AUX sampling won't take place there. Signed-off-by: Alexander Shishkin <[email protected]> --- kernel/events/core.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/kernel/events/core.c b/kernel/events/core.c index 4e1a1bf8d867..0f5cd1b08dbd 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6299,6 +6299,12 @@ static void perf_event_addr_filters_exec(struct perf_event *event, void *data) if (!has_addr_filter(event)) return; + /* + * if sampling kicks in in the critical section, + * we risk spinlock recursion on the ifh::lock + */ + perf_pmu_disable(event->pmu); + raw_spin_lock_irqsave(&ifh->lock, flags); list_for_each_entry(filter, &ifh->list, entry) { if (filter->inode) { @@ -6313,6 +6319,8 @@ static void perf_event_addr_filters_exec(struct perf_event *event, void *data) event->addr_filters_gen++; raw_spin_unlock_irqrestore(&ifh->lock, flags); + perf_pmu_enable(event->pmu); + if (restart) perf_event_stop(event, 1); } @@ -6993,6 +7001,8 @@ static void __perf_addr_filters_adjust(struct perf_event *event, void *data) if (!file) return; + perf_pmu_disable(event->pmu); + raw_spin_lock_irqsave(&ifh->lock, flags); list_for_each_entry(filter, &ifh->list, entry) { if (perf_addr_filter_match(filter, file, off, @@ -7008,6 +7018,8 @@ static void __perf_addr_filters_adjust(struct perf_event *event, void *data) event->addr_filters_gen++; raw_spin_unlock_irqrestore(&ifh->lock, flags); + perf_pmu_enable(event->pmu); + if (restart) perf_event_stop(event, 1); } @@ -8261,6 +8273,8 @@ static void perf_event_addr_filters_apply(struct perf_event *event) down_read(&mm->mmap_sem); + perf_pmu_disable(event->pmu); + raw_spin_lock_irqsave(&ifh->lock, flags); list_for_each_entry(filter, &ifh->list, entry) { event->addr_filters_offs[count] = 0; @@ -8279,6 +8293,8 @@ static void perf_event_addr_filters_apply(struct perf_event *event) event->addr_filters_gen++; raw_spin_unlock_irqrestore(&ifh->lock, flags); + perf_pmu_enable(event->pmu); + up_read(&mm->mmap_sem); mmput(mm); -- 2.17.1
