From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B64EB20010A; Mon, 28 Sep 2026 14:29:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790605776; cv=none; b=Kt2ZBOsTHB8EDP2OlNLRU3HMv9aBdKfd9IoipXQMZLfGqxMqSQ3bn1KsdJG6NA9kTX480biYCcOa1ySKllXy42HhA6rqXsxW27+FE1BALuMVCK6hGZg/LO/8V2Qh9DgoxeRhgwN6dpQFL/eZNAr7hn5fvhZ887wDe8GSyXsbGi0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790605776; c=relaxed/simple; bh=IyMAtB9cbjsiIH/TGlu9jcnjk9wBC5bT3ub/aG6oRTk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=L9h3kxCnwOtmGWXjWKOTj0uqRAbPHE1lbNU59NMiLHTuP7KYdyrLoleVUkUgX72G6NqMTKVtav0FP86ecoqNSnsTaY7udobq7b+lhjwXs7clpGVP0tQXf2LjfMySBDUzy5boXWMmuSGzktKc2BiDXAiSwdVSpg/xSF8k/VWDwwY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Cllssm3L; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Cllssm3L" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 943EE1F00893; Mon, 28 Sep 2026 14:29:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790605775; bh=hENkM5jtUQlxWUVRVmB2Y3HGiTekSFtmW2vKEK3DXWs=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Cllssm3LYvSI8akntOXuWzEnLDlf+FJFyRcfB2c1OMLaPesPIIxKYPuXVNS/5EOh8 YOtumZ+eJ1+ztycOb0yLkK324ss9N4cbSE1lAxabBLjSCK+0UWaptAwURo2LKcaTtB 0sVF03gnmjkGEnli62PjGD/xwxSaVqMmZGvJhE+zwW5EDs7PqCB2a8GXK6TLyXeZys 7/ydXGqnFJgpUb19ZUIbZm2UCuuKoeT0IVdkQZpKB2pISoOrGWLLAxHbagBtFwR9to HT8V+dsWBp0EY/Q1lG+NsY+GHeQCl3rBCpNcQBk99+qJ4CUVrBFA1nvD3ZNoqzMVsW O1zHcMolz7c9g== From: "Masami Hiramatsu (Google)" To: "Paul E . McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki , Thomas Graf , Herbert Xu , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Steven Rostedt , Masami Hiramatsu , Andrew Morton Cc: Mathieu Desnoyers , Lai Jiangshan , Zqiang , John Fastabend , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Ihor Solodrai , rcu@vger.kernel.org, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, bpf@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [RFC PATCH 1/3] rcu/tasks: Export call_rcu_tasks_rude() Date: Mon, 28 Sep 2026 23:29:27 +0900 Message-ID: <179060576723.372125.8212099501235098804.stgit@devnote2> X-Mailer: git-send-email 2.43.0 In-Reply-To: <179060575297.372125.10581329083761385407.stgit@devnote2> References: <179060575297.372125.10581329083761385407.stgit@devnote2> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit From: Masami Hiramatsu (Google) Currently call_rcu_tasks_rude() is static and private to kernel/rcu/tasks.h, while synchronize_rcu_tasks_rude() is exported. Subsystems that execute handlers under preempt_disable() (such as fprobe and BPF kprobe-multi) cannot safely wait on synchronize_rcu_tasks_rude() in atomic or asynchronous contexts without an asynchronous call_rcu_tasks_rude() variant. Make call_rcu_tasks_rude() non-static, declare it in include/linux/rcupdate.h, and export it via EXPORT_SYMBOL_GPL(). Also provide fallbacks to call_rcu when Tasks Rude RCU is not configured. Assisted-by: LLM Signed-off-by: Masami Hiramatsu (Google) --- include/linux/rcupdate.h | 6 ++++++ kernel/rcu/tasks.h | 8 +++----- 2 files changed, 9 insertions(+), 5 deletions(-) diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 44c07a66edff..dca61b52dc8c 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -198,7 +198,11 @@ void rcu_tasks_torture_stats_print(char *tt, char *tf); # ifdef CONFIG_TASKS_RUDE_RCU void synchronize_rcu_tasks_rude(void); +void call_rcu_tasks_rude(struct rcu_head *rhp, rcu_callback_t func); void rcu_tasks_rude_torture_stats_print(char *tt, char *tf); +# else +# define call_rcu_tasks_rude call_rcu +# define synchronize_rcu_tasks_rude synchronize_rcu # endif #define rcu_note_voluntary_context_switch(t) rcu_tasks_qs(t, false) @@ -210,6 +214,8 @@ void exit_tasks_rcu_finish(void); #define rcu_note_voluntary_context_switch(t) do { } while (0) #define call_rcu_tasks call_rcu #define synchronize_rcu_tasks synchronize_rcu +#define call_rcu_tasks_rude call_rcu +#define synchronize_rcu_tasks_rude synchronize_rcu static inline void exit_tasks_rcu_start(void) { } static inline void exit_tasks_rcu_finish(void) { } #endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */ diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 627295396cd9..f0b524d5f3f5 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -1355,7 +1355,7 @@ static void rcu_tasks_rude_wait_gp(struct rcu_tasks *rtp) schedule_on_each_cpu(rcu_tasks_be_rude); } -static void call_rcu_tasks_rude(struct rcu_head *rhp, rcu_callback_t func); +void call_rcu_tasks_rude(struct rcu_head *rhp, rcu_callback_t func); DEFINE_RCU_TASKS(rcu_tasks_rude, rcu_tasks_rude_wait_gp, call_rcu_tasks_rude, "RCU Tasks Rude"); @@ -1376,14 +1376,12 @@ DEFINE_RCU_TASKS(rcu_tasks_rude, rcu_tasks_rude_wait_gp, call_rcu_tasks_rude, * * See the description of call_rcu() for more detailed information on * memory ordering guarantees. - * - * This is no longer exported, and is instead reserved for use by - * synchronize_rcu_tasks_rude(). */ -static void call_rcu_tasks_rude(struct rcu_head *rhp, rcu_callback_t func) +void call_rcu_tasks_rude(struct rcu_head *rhp, rcu_callback_t func) { call_rcu_tasks_generic(rhp, func, &rcu_tasks_rude); } +EXPORT_SYMBOL_GPL(call_rcu_tasks_rude); /** * synchronize_rcu_tasks_rude - wait for a rude rcu-tasks grace period