Messages in this thread Patch in this message | | | From | Alexander Shishkin <> | Subject | [RFC PATCH 5/6] perf: Disable PMU around address filter adjustment | Date | Fri, 23 Sep 2016 14:27:25 +0300 |
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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.shishkin@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
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