diff options
| -rw-r--r-- | kernel/perf_event.c | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c index b782b7a79f00..76be4c7bf08e 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -6494,7 +6494,6 @@ int perf_event_init_context(struct task_struct *child, int ctxn) raw_spin_lock_irqsave(&parent_ctx->lock, flags); parent_ctx->rotate_disable = 0; - raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); child_ctx = child->perf_event_ctxp[ctxn]; @@ -6502,12 +6501,11 @@ int perf_event_init_context(struct task_struct *child, int ctxn) /* * Mark the child context as a clone of the parent * context, or of whatever the parent is a clone of. - * Note that if the parent is a clone, it could get - * uncloned at any point, but that doesn't matter - * because the list of events and the generation - * count can't have changed since we took the mutex. + * + * Note that if the parent is a clone, the holding of + * parent_ctx->lock avoids it from being uncloned. */ - cloned_ctx = rcu_dereference(parent_ctx->parent_ctx); + cloned_ctx = parent_ctx->parent_ctx; if (cloned_ctx) { child_ctx->parent_ctx = cloned_ctx; child_ctx->parent_gen = parent_ctx->parent_gen; @@ -6518,6 +6516,7 @@ int perf_event_init_context(struct task_struct *child, int ctxn) get_ctx(child_ctx->parent_ctx); } + raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); mutex_unlock(&parent_ctx->mutex); perf_unpin_context(parent_ctx); |