From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,T_DKIMWL_WL_HIGH,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7BF69C468BD for ; Sun, 9 Jun 2019 16:47:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 54589205ED for ; Sun, 9 Jun 2019 16:47:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560098879; bh=QCtxU2sR28pkPYBHfyAgs8ZVRZgw/+3pheZ7fz1NubI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=naVcKAkoCjdUe8OHcqleQx988XBRG7bOpeXQop9ZTb/l+Ba0ucqL5syTOwBcvgi+n imuTqjE9fm/Ka3sSBD4Vb7gVIe3joj1Xipqr92R+ocpYVsxc6BSfaxCeEjusJnwr1g CdG42++Suy86NAoDT00kk2etk9QmzKlgZJsajYmM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731035AbfFIQrz (ORCPT ); Sun, 9 Jun 2019 12:47:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:46704 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730968AbfFIQrx (ORCPT ); Sun, 9 Jun 2019 12:47:53 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1E1DD206C3; Sun, 9 Jun 2019 16:47:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560098872; bh=QCtxU2sR28pkPYBHfyAgs8ZVRZgw/+3pheZ7fz1NubI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1UcUHyrDibmlP2rB5MB/bF7/3+NONSbtb/iu8q2XKyu2Cx3X0K6rinGs1A4Ag7KPf Lu/uPMq3EEFsZbP/gfd+5AafR5IDyZUlAiadx/AASPzyACl8XgdnKy/aQ3d+bBFQl7 hKiDWx8/RifDCRMtmYbY9byADfJt4CCV+E7HpDic= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Yihao Wu , Jeff Layton , Anna Schumaker Subject: [PATCH 4.19 20/51] NFSv4.1: Again fix a race where CB_NOTIFY_LOCK fails to wake a waiter Date: Sun, 9 Jun 2019 18:42:01 +0200 Message-Id: <20190609164128.246232064@linuxfoundation.org> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190609164127.123076536@linuxfoundation.org> References: <20190609164127.123076536@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Yihao Wu commit 52b042ab9948cc367b61f9ca9c18603aa7813c3a upstream. Commit b7dbcc0e433f "NFSv4.1: Fix a race where CB_NOTIFY_LOCK fails to wake a waiter" found this bug. However it didn't fix it. This commit replaces schedule_timeout() with wait_woken() and default_wake_function() with woken_wake_function() in function nfs4_retry_setlk() and nfs4_wake_lock_waiter(). wait_woken() uses memory barriers in its implementation to avoid potential race condition when putting a process into sleeping state and then waking it up. Fixes: a1d617d8f134 ("nfs: allow blocking locks to be awoken by lock callbacks") Cc: stable@vger.kernel.org #4.9+ Signed-off-by: Yihao Wu Reviewed-by: Jeff Layton Signed-off-by: Anna Schumaker Signed-off-by: Greg Kroah-Hartman --- fs/nfs/nfs4proc.c | 24 +++++++----------------- 1 file changed, 7 insertions(+), 17 deletions(-) --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -6850,7 +6850,6 @@ struct nfs4_lock_waiter { struct task_struct *task; struct inode *inode; struct nfs_lowner *owner; - bool notified; }; static int @@ -6872,13 +6871,13 @@ nfs4_wake_lock_waiter(wait_queue_entry_t /* Make sure it's for the right inode */ if (nfs_compare_fh(NFS_FH(waiter->inode), &cbnl->cbnl_fh)) return 0; - - waiter->notified = true; } /* override "private" so we can use default_wake_function */ wait->private = waiter->task; - ret = autoremove_wake_function(wait, mode, flags, key); + ret = woken_wake_function(wait, mode, flags, key); + if (ret) + list_del_init(&wait->entry); wait->private = waiter; return ret; } @@ -6887,7 +6886,6 @@ static int nfs4_retry_setlk(struct nfs4_state *state, int cmd, struct file_lock *request) { int status = -ERESTARTSYS; - unsigned long flags; struct nfs4_lock_state *lsp = request->fl_u.nfs4_fl.owner; struct nfs_server *server = NFS_SERVER(state->inode); struct nfs_client *clp = server->nfs_client; @@ -6897,8 +6895,7 @@ nfs4_retry_setlk(struct nfs4_state *stat .s_dev = server->s_dev }; struct nfs4_lock_waiter waiter = { .task = current, .inode = state->inode, - .owner = &owner, - .notified = false }; + .owner = &owner}; wait_queue_entry_t wait; /* Don't bother with waitqueue if we don't expect a callback */ @@ -6911,21 +6908,14 @@ nfs4_retry_setlk(struct nfs4_state *stat add_wait_queue(q, &wait); while(!signalled()) { - waiter.notified = false; status = nfs4_proc_setlk(state, cmd, request); if ((status != -EAGAIN) || IS_SETLK(cmd)) break; status = -ERESTARTSYS; - spin_lock_irqsave(&q->lock, flags); - if (waiter.notified) { - spin_unlock_irqrestore(&q->lock, flags); - continue; - } - set_current_state(TASK_INTERRUPTIBLE); - spin_unlock_irqrestore(&q->lock, flags); - - freezable_schedule_timeout(NFS4_LOCK_MAXTIMEOUT); + freezer_do_not_count(); + wait_woken(&wait, TASK_INTERRUPTIBLE, NFS4_LOCK_MAXTIMEOUT); + freezer_count(); } finish_wait(q, &wait);