From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-118.mta0.migadu.com [91.218.175.118]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2469A38C2B8 for ; Fri, 11 Sep 2026 08:01:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.118 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789113662; cv=none; b=lyhIgn/r3Crnp+NTUvUwgNrNPrnjGZAmne//2irC9/F467+17fCW5S3JgbiocL69AS66MvXIEZzqn8w1zcROyDibyRUW0FZCB+jYU29rRyxFtg64w/jO+ZzR7mohRMJqk4IC28Zt4QYJ/5nglo6qhjfcm1Gs/ZWIowN5BJvz4i8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789113662; c=relaxed/simple; bh=vF8dJvwfO0k4j+Rhq4+Quj7N58x+aoewGF5Ku9uTa1M=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=WA9zceVkt5cU6ShBu7uft3cqVs6dFszFNdLr7a6ByJJVWisO1gAaCKFwWTeupWadSUzcmXtuK2hKiOv14M6bOv3hTvsjm7oWQ4GHDwHzzoenqregEJuDTQYwlisKWnJQZpErybxDBKePHnvhWuUxdrfzNr4+p79hl3YatvptWVE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=MfiO3KUv; arc=none smtp.client-ip=91.218.175.118 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="MfiO3KUv" X-Envelope-To: linux-security-module@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=vF8dJvwfO0k4j+Rhq4+Quj7N58x+aoewGF5Ku9uTa1M=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1789113659; v=1; x=1789718459; b=MfiO3KUvs2ayehQUR1oT0ZYnafFK1ZKlw7J9qdatwAyI/n6a/U6yECelsZHxvQWoVXt7Uoql 4lsOlfdsyJl7p8dAvZr7j1e6OvMOxkFXxvadZV04xuhUVcJk2WYiesYAfPvUZaDpHAaUSnbWEhj 3b6wjlKFsdHJqEHIHAd+LkXU= X-Envelope-To: linux-security-module@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 92b4a417acb68777; Fri, 11 Sep 2026 08:00:58 +0000 X-Mizu-Trace-ID: 92b4a417acb68777 X-Migadu-Flow: FLOW_OUT From: Ye Liu To: "Paul E. McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki Cc: Ye Liu , Michal Hocko , SJ Park , Lorenzo Stoakes , Oleg Nesterov , peterz@infradead.org, mingo@redhat.com, rostedt@goodmis.org, jpoimboe@kernel.org, mic@digikod.net, tglx@kernel.org, akpm@linux-foundation.org, david@kernel.org, linmiaohe@huawei.com, nao.horiguchi@gmail.com, rafael@kernel.org, gnoack3000@gmail.com, gourry@gourry.net, rientjes@google.com, shakeel.butt@linux.dev, xu.xin16@zte.com.cn, chengming.zhou@linux.dev, will@kernel.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, tony.luck@intel.com, reinette.chatre@intel.com, x86@kernel.org, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, pavel@kernel.org, lance.yang@linux.dev, mhiramat@kernel.org, pmladek@suse.com, longman@redhat.com, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, qiang.zhang@linux.dev, dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, kprateek.nayak@amd.com, mark.rutland@arm.com, Dave.Martin@arm.com, james.morse@arm.com, babu.moger@amd.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, rcu@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH v3 09/15] rcu: convert process/thread iterator to for_each_process_thread_rculock Date: Fri, 11 Sep 2026 15:57:54 +0800 Message-Id: <20260911075800.491472-10-ye.liu@linux.dev> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20260911075800.491472-1-ye.liu@linux.dev> References: <20260911075800.491472-1-ye.liu@linux.dev> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Ye Liu Replace the manual rcu_read_lock()/rcu_read_unlock() pair combined with for_each_process_thread() loop in kernel/rcu/update.c with for_each_process_thread_rculock(), which scopes the RCU read lock to the loop body via scoped_guard(rcu). No functional change. Signed-off-by: Ye Liu Acked-by: Michal Hocko Reviewed-by: SJ Park Reviewed-by: Lorenzo Stoakes (ARM) Reviewed-by: Oleg Nesterov --- Changes in v3: - Split from kernel/ patch in v2 (Peter Zijlstra, Steven Rostedt) Changes in v2: - Rename *_rcu to *_rculock kernel/rcu/update.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index 2a778b8ab4ad..d8e0b5896db9 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -548,15 +548,13 @@ void synchronize_rcu_trivial_preempt(void) struct task_struct *t; smp_mb(); // Order prior accesses before grace-period start. - rcu_read_lock(); // Protect task list. - for_each_process_thread(g, t) { + for_each_process_thread_rculock(g, t) { if (t == current) continue; // Don't deadlock on ourselves! // Order later rcu_read_lock() on other tasks after QS. while (smp_load_acquire(&t->rcu_trivial_preempt_nesting)) continue; } - rcu_read_unlock(); } EXPORT_SYMBOL_GPL(synchronize_rcu_trivial_preempt); #endif // #if IS_ENABLED(CONFIG_TRIVIAL_PREEMPT_RCU) -- 2.25.1