perf: fix perf bug in fork()

[platform/adaptation/renesas_rcar/renesas_kernel.git] / kernel / events / core.c

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 0e7fea7..4ced342 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1516,6 +1516,11 @@ retry:
         */
        if (ctx->is_active) {
                raw_spin_unlock_irq(&ctx->lock);
+               /*
+                * Reload the task pointer, it might have been changed by
+                * a concurrent perf_event_context_sched_out().
+                */
+               task = ctx->task;
                goto retry;
        }
 
@@ -1957,6 +1962,11 @@ retry:
         */
        if (ctx->is_active) {
                raw_spin_unlock_irq(&ctx->lock);
+               /*
+                * Reload the task pointer, it might have been changed by
+                * a concurrent perf_event_context_sched_out().
+                */
+               task = ctx->task;
                goto retry;
        }
 
@@ -2311,7 +2321,7 @@ static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
        next_parent = rcu_dereference(next_ctx->parent_ctx);
 
        /* If neither context have a parent context; they cannot be clones. */
-       if (!parent && !next_parent)
+       if (!parent || !next_parent)
                goto unlock;
 
        if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
@@ -7826,8 +7836,10 @@ int perf_event_init_task(struct task_struct *child)
 
        for_each_task_context_nr(ctxn) {
                ret = perf_event_init_context(child, ctxn);
-               if (ret)
+               if (ret) {
+                       perf_event_free_task(child);
                        return ret;
+               }
        }
 
        return 0;