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 <alexander.shish...@linux.intel.com>
---
kernel/events/core.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index fdb20fdeb1..f6582df1c9 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6377,6 +6377,12 @@ 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) {
@@ -6387,6 +6393,8 @@ static void perf_event_addr_filters_exec(struct
perf_event *event, void *data)
count++;
}
+ perf_pmu_enable(event->pmu);
+
if (restart)
event->addr_filters_gen++;
raw_spin_unlock_irqrestore(&ifh->lock, flags);
@@ -6942,6 +6950,8 @@ 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,
@@ -6953,6 +6963,8 @@ static void __perf_addr_filters_adjust(struct perf_event
*event, void *data)
count++;
}
+ perf_pmu_enable(event->pmu);
+
if (restart)
event->addr_filters_gen++;
raw_spin_unlock_irqrestore(&ifh->lock, flags);
@@ -8126,6 +8138,8 @@ 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;
@@ -8144,6 +8158,8 @@ 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);
--
2.9.3
