From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 E383A1662E9; Fri, 24 Jan 2025 23:09:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737760169; cv=none; b=HZCyC1ego5OAqMWefKMeBZOX/lcZPrw/v/sl0t1wK/nUGs09NVv3rdsLasKchPhjyJWyjdR1Q4GLyfVb/UoCh8b5pWGRtBAU5G19TEhQvSHnSTVkufhoCxbTENALVbTOfqdnESo1kKnuQx66F5SW1/m5KJ2bkk+Lquw8p0OZMJQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737760169; c=relaxed/simple; bh=WsAoZz2CDcE9T6s2PSn0rUpzTNYd7l6+ooU+g77l96w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=gn3zdghPYs4i3i3t9ok+Yq4THpmvIkEpiUQXpm3gowSHTFkvLWc6qMwdutCAImp3pz4bx/Y9SYwcnqFbqU9vT/ZCXg0dNblMFrL3NzePw5zpkKXFO5ra4B3hfzLT5F72xbYbbOLLxycUoACimXQ7O8FazRQVy72BH2ib1gJXp7A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IVWL6h4Q; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IVWL6h4Q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9581AC4CED2; Fri, 24 Jan 2025 23:09:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1737760168; bh=WsAoZz2CDcE9T6s2PSn0rUpzTNYd7l6+ooU+g77l96w=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=IVWL6h4QOYLIWJtRkkrKTLCGcWtDixfA1C8DLfhoTIhZfou2W0qjVhvEAQGylHaFh mmGsDtsCFzPX6z3PBuPVsHQL2OLvaTIS08FiE4DdgOPw+jOTSCnyBGcWfp6ceFayJa rErVIBj2EAN7Ws/mE5v4fYkxLVlKLLqch1XJ9IgAUc1JhEnKdIh6eBO+2KhxdWG6ql TY9rNXOKp5vmBGQZOu8Xw0mI3Cfklds7jmDsRcFViVoesaWfszOgSqy2pkeyH8dtP/ qQh+AvTdE6KQsswfHgJWuOHDiz+hFXGeQ4jD8OA+UEFQHrumng7au+bbZgUGIWRV1w ztZO2NG3Cx4Rg== Date: Fri, 24 Jan 2025 13:09:27 -1000 From: Tejun Heo To: Sebastian Andrzej Siewior Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Michal =?iso-8859-1?Q?Koutn=FD?= , "Paul E. McKenney" , Boqun Feng , Greg Kroah-Hartman , Hillf Danton , Johannes Weiner , Marco Elver , Zefan Li , tglx@linutronix.de Subject: Re: [PATCH v4 1/6] kernfs: Acquire kernfs_rwsem in kernfs_notify_workfn(). Message-ID: References: <20250124174614.866884-1-bigeasy@linutronix.de> <20250124174614.866884-2-bigeasy@linutronix.de> 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=us-ascii Content-Disposition: inline In-Reply-To: <20250124174614.866884-2-bigeasy@linutronix.de> Hello, On Fri, Jan 24, 2025 at 06:46:09PM +0100, Sebastian Andrzej Siewior wrote: > @@ -911,6 +911,7 @@ static void kernfs_notify_workfn(struct work_struct *work) > /* kick fsnotify */ > > down_read(&root->kernfs_supers_rwsem); > + down_read(&root->kernfs_rwsem); > list_for_each_entry(info, &kernfs_root(kn)->supers, node) { > struct kernfs_node *parent; > struct inode *p_inode = NULL; > @@ -948,6 +949,7 @@ static void kernfs_notify_workfn(struct work_struct *work) > } > > up_read(&root->kernfs_supers_rwsem); > + up_read(&root->kernfs_rwsem); > kernfs_put(kn); > goto repeat; Maybe match the locking and unlocking order so that what's locked last is unlocked first? Other than that, Acked-by: Tejun Heo Thanks. -- tejun