From patchwork Tue Apr 5 07:16:09 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 557777 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5E254C433F5 for ; Tue, 5 Apr 2022 08:57:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343671AbiDEI51 (ORCPT ); Tue, 5 Apr 2022 04:57:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48444 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235475AbiDEIjx (ORCPT ); Tue, 5 Apr 2022 04:39:53 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5B928647A; Tue, 5 Apr 2022 01:33:28 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 12AAAB81B92; Tue, 5 Apr 2022 08:33:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7181CC385A0; Tue, 5 Apr 2022 08:33:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1649147605; bh=4YZvBY0mns0pA0OpwTjHs7wx4nUfBNRycY/uSHjyi7M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=a2hzNNNKami/DAmGayujLMih7UKqdVnOjC+jxVGb4gTtJMUkkjpFN+XxLSDto3ZYj TYP6nNgww6YppxqCkAoNqp3c6PbQCdtCENouvZlW+d1yk0UhC1HzC2pfoUFYY149Je AxBRIUXHPaTCjDw8CW420bRT5xyisJI2pi46g8lc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, kernel test robot , Ronnie Sahlberg , Steve French Subject: [PATCH 5.16 0056/1017] cifs: we do not need a spinlock around the tree access during umount Date: Tue, 5 Apr 2022 09:16:09 +0200 Message-Id: <20220405070355.847749692@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220405070354.155796697@linuxfoundation.org> References: <20220405070354.155796697@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ronnie Sahlberg commit 9a14b65d590105d393b63f5320e1594edda7c672 upstream. Remove the spinlock around the tree traversal as we are calling possibly sleeping functions. We do not need a spinlock here as there will be no modifications to this tree at this point. This prevents warnings like this to occur in dmesg: [ 653.774996] BUG: sleeping function called from invalid context at kernel/loc\ king/mutex.c:280 [ 653.775088] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1827, nam\ e: umount [ 653.775152] preempt_count: 1, expected: 0 [ 653.775191] CPU: 0 PID: 1827 Comm: umount Tainted: G W OE 5.17.0\ -rc7-00006-g4eb628dd74df #135 [ 653.775195] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-\ 1.fc33 04/01/2014 [ 653.775197] Call Trace: [ 653.775199] [ 653.775202] dump_stack_lvl+0x34/0x44 [ 653.775209] __might_resched.cold+0x13f/0x172 [ 653.775213] mutex_lock+0x75/0xf0 [ 653.775217] ? __mutex_lock_slowpath+0x10/0x10 [ 653.775220] ? _raw_write_lock_irq+0xd0/0xd0 [ 653.775224] ? dput+0x6b/0x360 [ 653.775228] cifs_kill_sb+0xff/0x1d0 [cifs] [ 653.775285] deactivate_locked_super+0x85/0x130 [ 653.775289] cleanup_mnt+0x32c/0x4d0 [ 653.775292] ? path_umount+0x228/0x380 [ 653.775296] task_work_run+0xd8/0x180 [ 653.775301] exit_to_user_mode_loop+0x152/0x160 [ 653.775306] exit_to_user_mode_prepare+0x89/0xd0 [ 653.775315] syscall_exit_to_user_mode+0x12/0x30 [ 653.775322] do_syscall_64+0x48/0x90 [ 653.775326] entry_SYSCALL_64_after_hwframe+0x44/0xae Fixes: 187af6e98b44e5d8f25e1d41a92db138eb54416f ("cifs: fix handlecache and multiuser") Reported-by: kernel test robot Cc: stable@vger.kernel.org Signed-off-by: Ronnie Sahlberg Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/cifs/cifsfs.c | 2 -- 1 file changed, 2 deletions(-) --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -265,7 +265,6 @@ static void cifs_kill_sb(struct super_bl dput(cifs_sb->root); cifs_sb->root = NULL; } - spin_lock(&cifs_sb->tlink_tree_lock); node = rb_first(root); while (node != NULL) { tlink = rb_entry(node, struct tcon_link, tl_rbnode); @@ -279,7 +278,6 @@ static void cifs_kill_sb(struct super_bl mutex_unlock(&cfid->fid_mutex); node = rb_next(node); } - spin_unlock(&cifs_sb->tlink_tree_lock); kill_anon_super(sb); cifs_umount(cifs_sb);