perf/core: Fix locking for children siblings group read

[karo-tx-linux.git] / kernel / events / core.c

diff --git a/kernel/events/core.c b/kernel/events/core.c
index c9cdbd3967709cfd8456c8e48ae09c2238936d32..c17c0881fd36aef7200f3991b12bdd5a4322b765 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -4372,7 +4372,9 @@ EXPORT_SYMBOL_GPL(perf_event_read_value);
 static int __perf_read_group_add(struct perf_event *leader,
                                        u64 read_format, u64 *values)
 {
+       struct perf_event_context *ctx = leader->ctx;
        struct perf_event *sub;
+       unsigned long flags;
        int n = 1; /* skip @nr */
        int ret;
 
@@ -4402,12 +4404,15 @@ static int __perf_read_group_add(struct perf_event *leader,
        if (read_format & PERF_FORMAT_ID)
                values[n++] = primary_event_id(leader);
 
+       raw_spin_lock_irqsave(&ctx->lock, flags);
+
        list_for_each_entry(sub, &leader->sibling_list, group_entry) {
                values[n++] += perf_event_count(sub);
                if (read_format & PERF_FORMAT_ID)
                        values[n++] = primary_event_id(sub);
        }
 
+       raw_spin_unlock_irqrestore(&ctx->lock, flags);
        return 0;
 }