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From: Guillaume Morin <guillaume@morinfr.org>
To: stable@vger.kernel.org, greg@kroah.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Al Viro <viro@zeniv.linux.org.uk>
Subject: [3.14] Additional fixes after dcache backports
Date: Thu, 3 Dec 2015 22:52:13 +0100	[thread overview]
Message-ID: <20151203215213.GA13221@bender.morinfr.org> (raw)

Greg,

The following commits were added to 3.14.51:
635fa0fd72cc974920ec3e3b23f50bde1eba3237 dcache: don't need rcu in shrink_dentry_list() 
85903ac93619905fe0f07e85dac57324a0936759 more graceful recovery in umount_collect() 
c214cb82cdc744225d85899fc138251527f75fff don't remove from shrink list in select_collect() 

They create a livelock condition reported at the time in 3.15-rc4, see 
the thread "fs/dcache.c - BUG: soft lockup - CPU#5 stuck for 22s! 
[systemd-udevd:1667]":
https://groups.google.com/forum/#!msg/linux.kernel/e4tcY4cvHGg/tLZi97S02a0J

I believe you need to pick up the following changes to fix this issue
(they are already in 3.12 and were merged at the same time as the 3
patched mentioned above)

commit 7738a53cf49b034df6d52640f3a2af0c6a0fe0e2
Author: Al Viro <viro@zeniv.linux.org.uk>
Date:   Wed May 28 09:48:44 2014 -0400

    lift the "already marked killed" case into shrink_dentry_list()

commit 3074aefb9a84561ee8ca6ef8863fe2f4dcaaa4ae
Author: Al Viro <viro@zeniv.linux.org.uk>
Date:   Wed May 28 13:51:12 2014 -0400

    split dentry_kill()

commit c06507843fac3251bb8b5c4da8d6bf1964346694
Author: Al Viro <viro@zeniv.linux.org.uk>
Date:   Wed May 28 13:59:13 2014 -0400

    expand dentry_kill(dentry, 0) in shrink_dentry_list()

commit 7162622f8fcb2bb33776e2f61cf1c2b69107954d
Author: Al Viro <viro@zeniv.linux.org.uk>
Date:   Thu May 29 08:54:52 2014 -0400

    shrink_dentry_list(): take parent's ->d_lock earlier

commit a8ff4ae4f9db1042f352e73bda00b72e578b372e
Author: Al Viro <viro@zeniv.linux.org.uk>
Date:   Thu May 29 09:11:45 2014 -0400

    dealing with the rest of shrink_dentry_list() livelock

commit 1077afa0f8f8f59788c59d84436d98866933e1d4
Author: Al Viro <viro@zeniv.linux.org.uk>
Date:   Thu May 29 09:18:26 2014 -0400

    dentry_kill() doesn't need the second argument now

commit 76a9eb416abfdd524fcee2f834d77282d169d6f6
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sat May 31 09:13:21 2014 -0700

    dcache: add missing lockdep annotation

commit 50a754edcdd239bd4282ed3d5010425a46edd520
Author: Al Viro <viro@zeniv.linux.org.uk>
Date:   Thu Jun 12 00:29:13 2014 -0400

    lock_parent: don't step on stale ->d_parent of all-but-freed one

-- 
Guillaume Morin <guillaume@morinfr.org>

             reply	other threads:[~2015-12-03 21:52 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-03 21:52 Guillaume Morin [this message]
2015-12-04  1:52 ` [3.14] Additional fixes after dcache backports Ben Hutchings
2015-12-04  3:43   ` Guillaume Morin
2016-03-01  6:15     ` Greg KH

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