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

Commit-ID:     96746e731e1626545e343974ca4673739dceb31b
Gitweb:        https://git.kernel.org/tip/96746e731e1626545e343974ca4673739dceb31b
Author:        Dapeng Mi <dapeng1.mi@linux.intel.com>
AuthorDate:    Fri, 17 Jul 2026 16:03:36 +08:00
Committer:     Peter Zijlstra <peterz@infradead.org>
CommitterDate: Mon, 10 Aug 2026 15:05:47 +02:00

perf/x86: Free hybrid state on PMU init failure

If PMU initialization fails, for example in check_hw_exists(), hybrid
state can be left partially initialized: x86_pmu.hybrid_pmu is not freed
and perf_is_hybrid remains set. This can leak memory and leave stale
hybrid state reachable after a failed init path.

Add x86_pmu_free_hybrid() and use it on PMU init failure paths so all
hybrid-related state is consistently reset.

Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Falcon <thomas.falcon@intel.com>
Reviewed-by: Zide Chen <zide.chen@intel.com>
Link: https://patch.msgid.link/20260717080342.1879573-3-dapeng1.mi@linux.intel.com
---
 arch/x86/events/core.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 872d07a..6c63b27 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -2130,6 +2130,17 @@ void x86_pmu_show_pmu_cap(struct pmu *pmu)
 	pr_info("... global_ctrl mask:          %016llx\n", hybrid(pmu, intel_ctrl));
 }
 
+static void x86_pmu_free_hybrid(void)
+{
+	if (!x86_pmu.hybrid_pmu)
+		return;
+
+	static_branch_disable(&perf_is_hybrid);
+	kfree(x86_pmu.hybrid_pmu);
+	x86_pmu.hybrid_pmu = NULL;
+	x86_pmu.num_hybrid_pmus = 0;
+}
+
 static int __init init_hw_perf_events(void)
 {
 	struct x86_pmu_quirk *quirk;
@@ -2258,9 +2269,6 @@ static int __init init_hw_perf_events(void)
 			for (j = 0; j < i; j++)
 				perf_pmu_unregister(&x86_pmu.hybrid_pmu[j].pmu);
 			pr_warn("Failed to register hybrid PMUs\n");
-			kfree(x86_pmu.hybrid_pmu);
-			x86_pmu.hybrid_pmu = NULL;
-			x86_pmu.num_hybrid_pmus = 0;
 			goto out2;
 		}
 	}
@@ -2276,6 +2284,7 @@ out:
 pmi_unregister:
 	unregister_nmi_handler(NMI_LOCAL, "PMI");
 out_bad_pmu:
+	x86_pmu_free_hybrid();
 	memset(&x86_pmu, 0, sizeof(x86_pmu));
 	return err;
 }