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Path: news.gmane.org!not-for-mail
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From: Tejun Heo <tj@kernel.org>
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Newsgroups: gmane.linux.kernel,gmane.linux.usb.general
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Subject: [PATCH driver-core-linus] kernfs: make kernfs_deactivate() honor
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KERNFS_LOCKDEP flag
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Date: Wed, 29 Jan 2014 12:04:03 -0500
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Lines: 73
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Approved: news@gmane.org
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Message-ID: <20140129170403.GJ30842@htj.dyndns.org>
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References: <CAOJe8K20xx3o7HXH3E4pE3=G4pQ-nUf4LYF6sEwy5wYQE23+AA@mail.gmail.com>
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<Pine.LNX.4.44L0.1401291134070.11997-100000@netrider.rowland.org>
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X-Trace: ger.gmane.org 1391015061 4057 80.91.229.3 (29 Jan 2014 17:04:21 GMT)
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X-Complaints-To: usenet@ger.gmane.org
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NNTP-Posting-Date: Wed, 29 Jan 2014 17:04:21 +0000 (UTC)
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Cc: Denis Kirjanov <kda@linux-powerpc.org>,
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linux-kernel@vger.kernel.org, USB list <linux-usb@vger.kernel.org>
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To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
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Fabio Estevam <festevam@gmail.com>,
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Alan Stern <stern@rowland.harvard.edu>
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Original-X-From: linux-kernel-owner@vger.kernel.org Wed Jan 29 18:04:27 2014
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for glk-linux-kernel-3@plane.gmane.org; Wed, 29 Jan 2014 18:04:27 +0100
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In-Reply-To: <Pine.LNX.4.44L0.1401291134070.11997-100000@netrider.rowland.org>
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Xref: news.gmane.org gmane.linux.kernel:1637396 gmane.linux.usb.general:102347
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Archived-At: <http://permalink.gmane.org/gmane.linux.kernel/1637396>
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kernfs_deactivate() forgot to check whether KERNFS_LOCKDEP is set
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before performing lockdep annotations and ends up feeding
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uninitialized lockdep_map to lockdep triggering warning like the
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following on USB stick hotunplug.
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usb 1-2: USB disconnect, device number 2
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INFO: trying to register non-static key.
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the code is fine but needs lockdep annotation.
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turning off the locking correctness validator.
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CPU: 1 PID: 62 Comm: khubd Not tainted 3.13.0-work+ #82
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Hardware name: empty empty/S3992, BIOS 080011 10/26/2007
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ffff880065ca7f60 ffff88013a4ffa08 ffffffff81cfb6bd 0000000000000002
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ffff88013a4ffac8 ffffffff810f8530 ffff88013a4fc710 0000000000000002
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ffff880100000000 ffffffff82a3db50 0000000000000001 ffff88013a4fc710
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Call Trace:
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[<ffffffff81cfb6bd>] dump_stack+0x4e/0x7a
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[<ffffffff810f8530>] __lock_acquire+0x1910/0x1e70
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[<ffffffff810f931a>] lock_acquire+0x9a/0x1d0
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[<ffffffff8127c75e>] kernfs_deactivate+0xee/0x130
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[<ffffffff8127d4c8>] kernfs_addrm_finish+0x38/0x60
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[<ffffffff8127d701>] kernfs_remove_by_name_ns+0x51/0xa0
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[<ffffffff8127b4f1>] remove_files.isra.1+0x41/0x80
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[<ffffffff8127b7e7>] sysfs_remove_group+0x47/0xa0
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[<ffffffff8127b873>] sysfs_remove_groups+0x33/0x50
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[<ffffffff8177d66d>] device_remove_attrs+0x4d/0x80
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[<ffffffff8177e25e>] device_del+0x12e/0x1d0
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[<ffffffff819722c2>] usb_disconnect+0x122/0x1a0
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[<ffffffff819749b5>] hub_thread+0x3c5/0x1290
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[<ffffffff810c6a6d>] kthread+0xed/0x110
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[<ffffffff81d0a56c>] ret_from_fork+0x7c/0xb0
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Fix it by making kernfs_deactivate() perform lockdep annotations only
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if KERNFS_LOCKDEP is set.
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Signed-off-by: Tejun Heo <tj@kernel.org>
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Reported-by: Fabio Estevam <festevam@gmail.com>
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Reported-by: Alan Stern <stern@rowland.harvard.edu>
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---
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fs/kernfs/dir.c | 12 ++++++++----
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1 file changed, 8 insertions(+), 4 deletions(-)
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diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
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index 5104cf5..bd6e18b 100644
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--- a/fs/kernfs/dir.c
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+++ b/fs/kernfs/dir.c
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@@ -187,19 +187,23 @@ static void kernfs_deactivate(struct kernfs_node *kn)
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kn->u.completion = (void *)&wait;
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- rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
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+ if (kn->flags & KERNFS_LOCKDEP)
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+ rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
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/* atomic_add_return() is a mb(), put_active() will always see
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* the updated kn->u.completion.
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*/
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v = atomic_add_return(KN_DEACTIVATED_BIAS, &kn->active);
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if (v != KN_DEACTIVATED_BIAS) {
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- lock_contended(&kn->dep_map, _RET_IP_);
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+ if (kn->flags & KERNFS_LOCKDEP)
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+ lock_contended(&kn->dep_map, _RET_IP_);
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wait_for_completion(&wait);
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}
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- lock_acquired(&kn->dep_map, _RET_IP_);
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- rwsem_release(&kn->dep_map, 1, _RET_IP_);
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+ if (kn->flags & KERNFS_LOCKDEP) {
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+ lock_acquired(&kn->dep_map, _RET_IP_);
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+ rwsem_release(&kn->dep_map, 1, _RET_IP_);
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+ }
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}
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/**
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