diff options
| author | Tejun Heo <tj@kernel.org> | 2014-02-03 23:02:54 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-02-08 03:42:40 +0400 |
| commit | a6607930b6cd829fc7f680b48a937d827e0bb931 (patch) | |
| tree | f85197a00523b06416fe964c599bfb74a625c400 /fs/kernfs/dir.c | |
| parent | fee0c54e28f6ca187add93dfca226a8093cfa931 (diff) | |
| download | linux-a6607930b6cd829fc7f680b48a937d827e0bb931.tar.xz | |
kernfs: make kernfs_deactivate() honor KERNFS_LOCKDEP flag
kernfs_deactivate() forgot to check whether KERNFS_LOCKDEP is set
before performing lockdep annotations and ends up feeding
uninitialized lockdep_map to lockdep triggering warning like the
following on USB stick hotunplug.
usb 1-2: USB disconnect, device number 2
INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
CPU: 1 PID: 62 Comm: khubd Not tainted 3.13.0-work+ #82
Hardware name: empty empty/S3992, BIOS 080011 10/26/2007
ffff880065ca7f60 ffff88013a4ffa08 ffffffff81cfb6bd 0000000000000002
ffff88013a4ffac8 ffffffff810f8530 ffff88013a4fc710 0000000000000002
ffff880100000000 ffffffff82a3db50 0000000000000001 ffff88013a4fc710
Call Trace:
[<ffffffff81cfb6bd>] dump_stack+0x4e/0x7a
[<ffffffff810f8530>] __lock_acquire+0x1910/0x1e70
[<ffffffff810f931a>] lock_acquire+0x9a/0x1d0
[<ffffffff8127c75e>] kernfs_deactivate+0xee/0x130
[<ffffffff8127d4c8>] kernfs_addrm_finish+0x38/0x60
[<ffffffff8127d701>] kernfs_remove_by_name_ns+0x51/0xa0
[<ffffffff8127b4f1>] remove_files.isra.1+0x41/0x80
[<ffffffff8127b7e7>] sysfs_remove_group+0x47/0xa0
[<ffffffff8127b873>] sysfs_remove_groups+0x33/0x50
[<ffffffff8177d66d>] device_remove_attrs+0x4d/0x80
[<ffffffff8177e25e>] device_del+0x12e/0x1d0
[<ffffffff819722c2>] usb_disconnect+0x122/0x1a0
[<ffffffff819749b5>] hub_thread+0x3c5/0x1290
[<ffffffff810c6a6d>] kthread+0xed/0x110
[<ffffffff81d0a56c>] ret_from_fork+0x7c/0xb0
Fix it by making kernfs_deactivate() perform lockdep annotations only
if KERNFS_LOCKDEP is set.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Fabio Estevam <festevam@gmail.com>
Reported-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/kernfs/dir.c')
| -rw-r--r-- | fs/kernfs/dir.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 5104cf5d25c5..bd6e18be6e1a 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -187,19 +187,23 @@ static void kernfs_deactivate(struct kernfs_node *kn) kn->u.completion = (void *)&wait; - rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_); + if (kn->flags & KERNFS_LOCKDEP) + rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_); /* atomic_add_return() is a mb(), put_active() will always see * the updated kn->u.completion. */ v = atomic_add_return(KN_DEACTIVATED_BIAS, &kn->active); if (v != KN_DEACTIVATED_BIAS) { - lock_contended(&kn->dep_map, _RET_IP_); + if (kn->flags & KERNFS_LOCKDEP) + lock_contended(&kn->dep_map, _RET_IP_); wait_for_completion(&wait); } - lock_acquired(&kn->dep_map, _RET_IP_); - rwsem_release(&kn->dep_map, 1, _RET_IP_); + if (kn->flags & KERNFS_LOCKDEP) { + lock_acquired(&kn->dep_map, _RET_IP_); + rwsem_release(&kn->dep_map, 1, _RET_IP_); + } } /** |