Re: [PATCH RFC 1/4] perf/core: Apply PERF_EVENT_IOC_MODIFY_ATTRIBUTES to children
flat view
From: Dmitry Vyukov <dvyukov@google.com>
Date: 2021-02-23 14:49:56
Also in:
linux-fsdevel, linux-m68k, lkml
On Tue, Feb 23, 2021 at 3:34 PM Marco Elver [off-list ref] wrote:
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>Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
quoted hunk ↗ jump to hunk
--- 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