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authorTejun Heo <tj@kernel.org>2014-02-03 23:02:54 +0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-02-08 03:42:40 +0400
commita6607930b6cd829fc7f680b48a937d827e0bb931 (patch)
treef85197a00523b06416fe964c599bfb74a625c400 /fs/kernfs
parentfee0c54e28f6ca187add93dfca226a8093cfa931 (diff)
downloadlinux-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')
-rw-r--r--fs/kernfs/dir.c12
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_);
+ }
}
/**