[tip: perf/core] perf/x86: Unregister PMI handler on PMU init failure

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

Commit-ID:     91787047b1dc52b1fee68b07f79af70aae5fce47
Gitweb:        https://git.kernel.org/tip/91787047b1dc52b1fee68b07f79af70aae5fce47
Author:        Dapeng Mi <[email protected]>
AuthorDate:    Fri, 17 Jul 2026 16:03:35 +08:00
Committer:     Peter Zijlstra <[email protected]>
CommitterDate: Mon, 10 Aug 2026 15:05:47 +02:00

perf/x86: Unregister PMI handler on PMU init failure

Fix an NMI handler leak in init_hw_perf_events(). When PMU
initialization fails after register_nmi_handler(), the error path
exits without calling unregister_nmi_handler(), leaving a stale
NMI_LOCAL "PMI" handler registered. Add the missing call before
clearing x86_pmu state.

Signed-off-by: Dapeng Mi <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Thomas Falcon <[email protected]>
Reviewed-by: Zide Chen <[email protected]>
Link: https://patch.msgid.link/[email protected]
---
 arch/x86/events/core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index af0b67f..872d07a 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2219,7 +2219,7 @@ static int __init init_hw_perf_events(void)
 	err = cpuhp_setup_state(CPUHP_PERF_X86_PREPARE, "perf/x86:prepare",
 				x86_pmu_prepare_cpu, x86_pmu_dead_cpu);
 	if (err)
-		return err;
+		goto pmi_unregister;
 
 	err = cpuhp_setup_state(CPUHP_AP_PERF_X86_STARTING,
 				"perf/x86:starting", x86_pmu_starting_cpu,
@@ -2273,6 +2273,8 @@ out1:
 	cpuhp_remove_state(CPUHP_AP_PERF_X86_STARTING);
 out:
 	cpuhp_remove_state(CPUHP_PERF_X86_PREPARE);
+pmi_unregister:
+	unregister_nmi_handler(NMI_LOCAL, "PMI");
 out_bad_pmu:
 	memset(&x86_pmu, 0, sizeof(x86_pmu));
 	return err;