From f6938a562a6249000de211a710807ebf0b8fdf26 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 16 Apr 2025 20:50:27 +0200 Subject: [PATCH] perf/core: Fix perf-stat / read() In the zeal to adjust all event->state checks to include the new REVOKED state, one adjustment was made in error. Notably it resulted in read() on the perf filedesc to stop working for any state lower than ERROR, specifically EXIT. This leads to problems with (among others) perf-stat, which wants to read the counts after a program has finished execution. Fixes: da916e96e2de ("perf: Make perf_pmu_unregister() useable") Reported-by: "Mi, Dapeng" Reported-by: James Clark Tested-by: James Clark Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Link: https://lkml.kernel.org/r/77036114-8723-4af9-a068-1d535f4e2e81@linaro.org Link: https://lore.kernel.org/r/20250417080725.GH38216@noisy.programming.kicks-ass.net --- kernel/events/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 2eb9cd5d86a1..e4d7a0c4b308 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6021,7 +6021,7 @@ __perf_read(struct perf_event *event, char __user *buf, size_t count) * error state (i.e. because it was pinned but it couldn't be * scheduled on to the CPU at some point). */ - if (event->state <= PERF_EVENT_STATE_ERROR) + if (event->state == PERF_EVENT_STATE_ERROR) return 0; if (count < event->read_size) -- 2.25.1