linux-kernel - [PATCH 2/5] perf: Move free outside of the mutex

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20241008183501.1354695-3-lucas.demarchi@intel.com>
Date: Tue,  8 Oct 2024 13:34:58 -0500
From: Lucas De Marchi <lucas.demarchi@...el.com>
To: linux-kernel@...r.kernel.org
Cc: dri-devel@...ts.freedesktop.org,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Umesh Nerlige Ramappa <umesh.nerlige.ramappa@...el.com>,
	Ian Rogers <irogers@...gle.com>,
	Tvrtko Ursulin <tvrtko.ursulin@...lia.com>,
	Lucas De Marchi <lucas.demarchi@...el.com>
Subject: [PATCH 2/5] perf: Move free outside of the mutex

It's not needed to hold the mutex to free the percpu variables stored in
pmu. Move them outside of the mutex protection in preparation for
possibly allowing them to live longer, according to the lifecycle of the
object owning/containing the pmu.

Signed-off-by: Lucas De Marchi <lucas.demarchi@...el.com>
---
 kernel/events/core.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 3b8b85adb10a..6395dbf67671 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11845,7 +11845,6 @@ void perf_pmu_unregister(struct pmu *pmu)
 	synchronize_srcu(&pmus_srcu);
 	synchronize_rcu();
 
-	free_percpu(pmu->pmu_disable_count);
 	idr_remove(&pmu_idr, pmu->type);
 	if (pmu_bus_running && pmu->dev && pmu->dev != PMU_NULL_DEV) {
 		if (pmu->nr_addr_filters)
@@ -11853,8 +11852,11 @@ void perf_pmu_unregister(struct pmu *pmu)
 		device_del(pmu->dev);
 		put_device(pmu->dev);
 	}
-	free_pmu_context(pmu);
+
 	mutex_unlock(&pmus_lock);
+
+	free_percpu(pmu->pmu_disable_count);
+	free_pmu_context(pmu);
 }
 EXPORT_SYMBOL_GPL(perf_pmu_unregister);
 
-- 
2.46.2