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 7FB70413220; Thu, 9 Jul 2026 13:48:59 +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=1783604941; cv=none; b=mxxpv8xy+McnL0wJIaxt4f/A6heXZ34DvqbsJ7KoTJ/dvY9g33dP9opkokHRwPH47g0xamMVupz526KNdog04ZiziUQbaMCjBU1jbqZ1Q00Z25NbM6vVlS/hP7I6cm0+qiggg4J/Ai7R9VePVtDU6FIPDBy+R74QnfQzDjrccVk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783604941; c=relaxed/simple; bh=eRMcAiOuqwRJ9E/b60wmYk87uBAXfk02+DExZWtKDFw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=sSn15c6a/nEv/9g7Hn2XJQ9PPwC+kEm4KN1xlt8cfLm4Mvvv7c3pUE/AF2Is2OCEafd2pqDQyHlMn55mk+tbKWBQKR74mlfgUPiA8YXNQFD88ryuCIlMk0mPUBg0xKOt732VZTyoG1iKpTIDfIK+mkOL5BAvHp2hORa1HW8Ksfw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SOVzGtrc; 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="SOVzGtrc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A5FDB1F000E9; Thu, 9 Jul 2026 13:48:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783604939; bh=eeVdWmPK2iRcl9KZ4593Orxhq2UxRdJT3z1nhO/WGzE=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=SOVzGtrcs6/I1aTFaU8Nb6SK9PtITqFnn7E74dwpVKeMa1T3v4JQBPBiUVm3S+OCu Mo8hoQvl6UGaMW8qq9cLVB84fch68lNctHJgHAapsskV9zbsfkH1HXXBGY48CCBIM0 CSicDs7d1/+a+BfOyrgidEXjU+2szj9t0Oeg2ucaVDXq2+HEnw8xzJMYF7JEpsdOA0 kqz8577/+UIcOEnvbCJqP/LZFaqf1Yw/wIhbcJL/C5JXel47oUF17odJMXOoc2IdnG jTxwb+Zv2KPgSUDepxHbSj5CgFe1NbTFL6ZCWodgBO93sm/uw5gQj4o2QqCKb9VnyW 77avilrYcznvQ== Date: Thu, 9 Jul 2026 15:48:56 +0200 From: Frederic Weisbecker To: Puranjay Mohan Cc: rcu@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, "Paul E. McKenney" , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Masami Hiramatsu , Davidlohr Bueso , Breno Leitao Subject: Re: [PATCH v1 05/11] rcu: Add RCU_GET_STATE_NOT_TRACKED for subsystems without expedited GPs Message-ID: References: <20260624132356.516959-1-puranjay@kernel.org> <20260624132356.516959-6-puranjay@kernel.org> 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=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260624132356.516959-6-puranjay@kernel.org> Le Wed, Jun 24, 2026 at 06:23:47AM -0700, Puranjay Mohan a écrit : > SRCU and Tasks RCU do not track expedited grace periods. When their > callback state is checked via poll_state_synchronize_rcu_full(), the > uninitialized or zeroed exp field could cause false-positive > completion detection. > > This commit adds an RCU_GET_STATE_NOT_TRACKED sentinel value (0x2) that > these subsystems can place into exp to indicate that expedited GP > tracking is not applicable. The expedited sequence check in > poll_state_synchronize_rcu_full() is guarded to skip entries marked with > this sentinel. > > This is needed to allow rcu_segcblist_advance() and rcu_accelerate_cbs() > to work with both normal and expedited grace periods via > get_state_synchronize_rcu_full() and poll_state_synchronize_rcu_full(). > > Reviewed-by: Paul E. McKenney > Signed-off-by: Puranjay Mohan Reviewed-by: Frederic Weisbecker -- Frederic Weisbecker SUSE Labs