From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:35336 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751894AbdHABR0 (ORCPT ); Mon, 31 Jul 2017 21:17:26 -0400 Subject: Patch "NFSv4.1: Fix a race where CB_NOTIFY_LOCK fails to wake a waiter" has been added to the 4.9-stable tree To: bcodding@redhat.com, Anna.Schumaker@Netapp.com, gregkh@linuxfoundation.org, jlayton@redhat.com Cc: , From: Date: Mon, 31 Jul 2017 18:17:18 -0700 Message-ID: <150155023815172@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled NFSv4.1: Fix a race where CB_NOTIFY_LOCK fails to wake a waiter to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: nfsv4.1-fix-a-race-where-cb_notify_lock-fails-to-wake-a-waiter.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From b7dbcc0e433f0f61acb89ed9861ec996be4f2b38 Mon Sep 17 00:00:00 2001 From: Benjamin Coddington Date: Fri, 28 Jul 2017 12:33:54 -0400 Subject: NFSv4.1: Fix a race where CB_NOTIFY_LOCK fails to wake a waiter From: Benjamin Coddington commit b7dbcc0e433f0f61acb89ed9861ec996be4f2b38 upstream. nfs4_retry_setlk() sets the task's state to TASK_INTERRUPTIBLE within the same region protected by the wait_queue's lock after checking for a notification from CB_NOTIFY_LOCK callback. However, after releasing that lock, a wakeup for that task may race in before the call to freezable_schedule_timeout_interruptible() and set TASK_WAKING, then freezable_schedule_timeout_interruptible() will set the state back to TASK_INTERRUPTIBLE before the task will sleep. The result is that the task will sleep for the entire duration of the timeout. Since we've already set TASK_INTERRUPTIBLE in the locked section, just use freezable_schedule_timout() instead. Fixes: a1d617d8f134 ("nfs: allow blocking locks to be awoken by lock callbacks") Signed-off-by: Benjamin Coddington Reviewed-by: Jeff Layton Signed-off-by: Anna Schumaker Signed-off-by: Greg Kroah-Hartman --- fs/nfs/nfs4proc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/nfs/nfs4proc.c +++ b/fs/nfs/nfs4proc.c @@ -6419,7 +6419,7 @@ nfs4_retry_setlk(struct nfs4_state *stat set_current_state(TASK_INTERRUPTIBLE); spin_unlock_irqrestore(&q->lock, flags); - freezable_schedule_timeout_interruptible(NFS4_LOCK_MAXTIMEOUT); + freezable_schedule_timeout(NFS4_LOCK_MAXTIMEOUT); } finish_wait(q, &wait); Patches currently in stable-queue which might be from bcodding@redhat.com are queue-4.9/nfsv4.1-fix-a-race-where-cb_notify_lock-fails-to-wake-a-waiter.patch