The following commit has been merged into the perf/urgent branch of tip:

Commit-ID:     18dbcbfabfffc4a5d3ea10290c5ad27f22b0d240
Gitweb:        https://git.kernel.org/tip/18dbcbfabfffc4a5d3ea10290c5ad27f22b0d240
Author:        Kan Liang <kan.liang@linux.intel.com>
AuthorDate:    Mon, 11 Aug 2025 11:26:44 -07:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Wed, 03 Sep 2025 10:10:59 +02:00

perf: Fix the POLL_HUP delivery breakage

The event_limit can be set by the PERF_EVENT_IOC_REFRESH to limit the
number of events. When the event_limit reaches 0, the POLL_HUP signal
should be sent. But it's missed.

The corresponding counter should be stopped when the event_limit reaches
0. It was implemented in the ARCH-specific code. However, since the
commit 9734e25fbf5a ("perf: Fix the throttle logic for a group"), all
the ARCH-specific code has been moved to the generic code. The code to
handle the event_limit was lost.

Add the event->pmu->stop(event, 0); back.

Fixes: 9734e25fbf5a ("perf: Fix the throttle logic for a group")
Closes: https://lore.kernel.org/lkml/aICYAqM5EQUlTqtX@li-2b55cdcc-350b-11b2-a85c-a78bff51fc11.ibm.com/
Reported-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Link: https://lkml.kernel.org/r/20250811182644.1305952-1-kan.liang@linux.intel.com
---
 kernel/events/core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 872122e..8201275 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -10330,6 +10330,7 @@ static int __perf_event_overflow(struct perf_event *event,
 		ret = 1;
 		event->pending_kill = POLL_HUP;
 		perf_event_disable_inatomic(event);
+		event->pmu->stop(event, 0);
 	}
 
 	if (event->attr.sigtrap) {