1 files changed, 18 insertions, 2 deletions

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 76c754e45d01..6859229497b1 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -839,7 +839,7 @@ static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
  */
 static void perf_cgroup_switch(struct task_struct *task, int mode)
 {
-	struct perf_cpu_context *cpuctx;
+	struct perf_cpu_context *cpuctx, *tmp;
 	struct list_head *list;
 	unsigned long flags;
 
@@ -850,7 +850,7 @@ static void perf_cgroup_switch(struct task_struct *task, int mode)
 	local_irq_save(flags);
 
 	list = this_cpu_ptr(&cgrp_cpuctx_list);
-	list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
+	list_for_each_entry_safe(cpuctx, tmp, list, cgrp_cpuctx_entry) {
 		WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
 
 		perf_ctx_lock(cpuctx, cpuctx->task_ctx);
@@ -3238,6 +3238,15 @@ static int perf_event_modify_breakpoint(struct perf_event *bp,
 	return err;
 }
 
+/*
+ * Copy event-type-independent attributes that may be modified.
+ */
+static void perf_event_modify_copy_attr(struct perf_event_attr *to,
+					const struct perf_event_attr *from)
+{
+	to->sig_data = from->sig_data;
+}
+
 static int perf_event_modify_attr(struct perf_event *event,
 				  struct perf_event_attr *attr)
 {
@@ -3260,10 +3269,17 @@ static int perf_event_modify_attr(struct perf_event *event,
 	WARN_ON_ONCE(event->ctx->parent_ctx);
 
 	mutex_lock(&event->child_mutex);
+	/*
+	 * Event-type-independent attributes must be copied before event-type
+	 * modification, which will validate that final attributes match the
+	 * source attributes after all relevant attributes have been copied.
+	 */
+	perf_event_modify_copy_attr(&event->attr, attr);
 	err = func(event, attr);
 	if (err)
 		goto out;
 	list_for_each_entry(child, &event->child_list, child_list) {
+		perf_event_modify_copy_attr(&child->attr, attr);
 		err = func(child, attr);
 		if (err)
 			goto out;