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Subject[PATCH RFC 1/4] perf/core: Apply PERF_EVENT_IOC_MODIFY_ATTRIBUTES to children
From
As with other ioctls (such as PERF_EVENT_IOC_{ENABLE,DISABLE}), fix up
handling of PERF_EVENT_IOC_MODIFY_ATTRIBUTES to also apply to children.

Link: https://lkml.kernel.org/r/YBqVaY8aTMYtoUnX@hirez.programming.kicks-ass.net
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Marco Elver <elver@google.com>
---
kernel/events/core.c | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 129dee540a8b..37a8297be164 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3179,16 +3179,36 @@ static int perf_event_modify_breakpoint(struct perf_event *bp,
static int perf_event_modify_attr(struct perf_event *event,
struct perf_event_attr *attr)
{
+ int (*func)(struct perf_event *, struct perf_event_attr *);
+ struct perf_event *child;
+ int err;
+
if (event->attr.type != attr->type)
return -EINVAL;

switch (event->attr.type) {
case PERF_TYPE_BREAKPOINT:
- return perf_event_modify_breakpoint(event, attr);
+ func = perf_event_modify_breakpoint;
+ break;
default:
/* Place holder for future additions. */
return -EOPNOTSUPP;
}
+
+ WARN_ON_ONCE(event->ctx->parent_ctx);
+
+ mutex_lock(&event->child_mutex);
+ err = func(event, attr);
+ if (err)
+ goto out;
+ list_for_each_entry(child, &event->child_list, child_list) {
+ err = func(child, attr);
+ if (err)
+ goto out;
+ }
+out:
+ mutex_unlock(&event->child_mutex);
+ return err;
}

static void ctx_sched_out(struct perf_event_context *ctx,
--
2.30.0.617.g56c4b15f3c-goog
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