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Sat, 19 Sep 2026 19:46:02 -0700 (PDT) Received: from kernel.tail6741c6.ts.net ([185.220.238.35]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-cc72ae71fe3sm1485971a12.8.2026.09.19.19.46.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 19 Sep 2026 19:46:01 -0700 (PDT) From: Kunwu Chan To: tj@kernel.org, jiangshanlai@gmail.com Cc: linux-kernel@vger.kernel.org, Kunwu Chan Subject: [PATCH] workqueue: Drop redundant rcu_read_lock() from dump functions Date: Sun, 20 Sep 2026 10:45:50 +0800 Message-ID: <20260920024550.2278408-1-kunwu.chan@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit show_all_workqueues() and show_cpu_pools_busy_workers() are called from contexts that already provide RCU read-side protection. show_all_workqueues() is called from wq_watchdog_timer_fn(), which runs in softirq context, and from sysrq_handle_showstate() through __handle_sysrq(), which holds rcu_read_lock(). show_cpu_pools_busy_workers() is called from wq_watchdog_timer_fn() as well. Drop the redundant RCU read-side locking from both functions. Signed-off-by: Kunwu Chan --- kernel/workqueue.c | 8 -------- 1 file changed, 8 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 3c034cbc5bb3..266c3549df0f 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -6711,8 +6711,6 @@ void show_all_workqueues(void) struct worker_pool *pool; int pi; - rcu_read_lock(); - pr_info("Showing busy workqueues and worker pools:\n"); list_for_each_entry_rcu(wq, &workqueues, list) @@ -6720,8 +6718,6 @@ void show_all_workqueues(void) for_each_pool(pool, pi) show_one_worker_pool(pool); - - rcu_read_unlock(); } /** @@ -7883,15 +7879,11 @@ static void show_cpu_pools_busy_workers(void) pr_info("Showing backtraces of busy workers in stalled worker pools:\n"); - rcu_read_lock(); - for_each_pool(pool, pi) { if (pool->cpu_stall) show_cpu_pool_busy_workers(pool); } - - rcu_read_unlock(); } /* -- 2.43.0