Re: [v2.6.26-rc1] possible circular locking in ecryptfs

[Ingo Molnar]

* Cyrill Gorcunov <gorcunov@xxxxxxxxx> wrote:

> [Ingo Molnar - Fri, May 09, 2008 at 11:44:23AM +0200]
> | 
> | * Ingo Molnar <mingo@xxxxxxx> wrote:
> | 
> | > x86.git testing found the following "possible circular locking" 
> | > lockdep warning, generated by the ecryptfs code:
> | 
> | the correct URL for the config is:
> | 
> |   http://redhat.com/~mingo/misc/config-Wed_May__7_16_17_31_CEST_2008.bad
> | 
> | this is reproducible, it happened a second time since i originally 
> | reported it.
> | 
> | 	Ingo
> 
> Hi Ingo, I've just sent patch, could you test it, please?
> 
> http://lkml.org/lkml/2008/5/10/20

that patch is now upstream - but see below there's still a circular 
dependency.

	Ingo

[   21.530026] 
[   21.530026] =======================================================
[   21.530026] [ INFO: possible circular locking dependency detected ]
[   21.530026] 2.6.26-rc2-sched-devel.git #1205
[   21.530026] -------------------------------------------------------
[   21.530026] multipath.stati/1379 is trying to acquire lock:
[   21.530026]  (&ecryptfs_daemon_hash_mux){--..}, at: [<c020cca2>] ecryptfs_miscdev_open+0x22/0x140
[   21.530026] 
[   21.530026] but task is already holding lock:
[   21.530026]  (misc_mtx){--..}, at: [<c02f4b92>] misc_open+0x22/0x120
[   21.530026] 
[   21.530026] which lock already depends on the new lock.
[   21.530026] 
[   21.530026] 
[   21.530026] the existing dependency chain (in reverse order) is:
[   21.530026] 
[   21.530026] -> #1 (misc_mtx){--..}:
[   21.530026]        [<c01438aa>] __lock_acquire+0xc3a/0x1100
[   21.530026]        [<c0143de6>] lock_acquire+0x76/0xa0
[   21.530026]        [<c05d032a>] mutex_lock_nested+0x7a/0x280
[   21.530026]        [<c02f4cb5>] misc_register+0x25/0x140
[   21.530026]        [<c020cb5c>] ecryptfs_init_ecryptfs_miscdev+0x2c/0x60
[   21.530026]        [<c020c5fe>] ecryptfs_init_messaging+0x1ee/0x280
[   21.530026]        [<c0837662>] ecryptfs_init+0xc2/0x1b0
[   21.530026]        [<c0824852>] kernel_init+0x132/0x250
[   21.530026]        [<c010365f>] kernel_thread_helper+0x7/0x10
[   21.530026]        [<ffffffff>] 0xffffffff
[   21.530026] 
[   21.530026] -> #0 (&ecryptfs_daemon_hash_mux){--..}:
[   21.530026]        [<c01436cd>] __lock_acquire+0xa5d/0x1100
[   21.530026]        [<c0143de6>] lock_acquire+0x76/0xa0
[   21.530026]        [<c05d032a>] mutex_lock_nested+0x7a/0x280
[   21.530026]        [<c020cca2>] ecryptfs_miscdev_open+0x22/0x140
[   21.530026]        [<c02f4bf2>] misc_open+0x82/0x120
[   21.530026]        [<c0187c26>] chrdev_open+0x86/0x150
[   21.530026]        [<c0183289>] __dentry_open+0xa9/0x260
[   21.530026]        [<c0183487>] nameidata_to_filp+0x47/0x60
[   21.530026]        [<c018fda4>] do_filp_open+0x184/0x7a0
[   21.530026]        [<c01830aa>] do_sys_open+0x4a/0xb0
[   21.530026]        [<c018317e>] sys_open+0x2e/0x40
[   21.530026]        [<c010330e>] syscall_call+0x7/0xb
[   21.530026]        [<ffffffff>] 0xffffffff
[   21.530026] 
[   21.530026] other info that might help us debug this:
[   21.530026] 
[   21.530026] 1 lock held by multipath.stati/1379:
[   21.530026]  #0:  (misc_mtx){--..}, at: [<c02f4b92>] misc_open+0x22/0x120
[   21.530026] 
[   21.530026] stack backtrace:
[   21.530026] Pid: 1379, comm: multipath.stati Not tainted 2.6.26-rc2-sched-devel.git #1205
[   21.530026]  [<c014179e>] print_circular_bug_tail+0x6e/0x80
[   21.530026]  [<c01436cd>] __lock_acquire+0xa5d/0x1100
[   21.530026]  [<c0142eec>] ? __lock_acquire+0x27c/0x1100
[   21.530026]  [<c0143de6>] lock_acquire+0x76/0xa0
[   21.530026]  [<c020cca2>] ? ecryptfs_miscdev_open+0x22/0x140
[   21.530026]  [<c020cca2>] ? ecryptfs_miscdev_open+0x22/0x140
[   21.530026]  [<c05d032a>] mutex_lock_nested+0x7a/0x280
[   21.530026]  [<c020cca2>] ? ecryptfs_miscdev_open+0x22/0x140
[   21.530026]  [<c020cca2>] ecryptfs_miscdev_open+0x22/0x140
[   21.530026]  [<c02f4bf2>] misc_open+0x82/0x120
[   21.530026]  [<c0187c26>] chrdev_open+0x86/0x150
[   21.530026]  [<c0183289>] __dentry_open+0xa9/0x260
[   21.530026]  [<c0183487>] nameidata_to_filp+0x47/0x60
[   21.530026]  [<c0187ba0>] ? chrdev_open+0x0/0x150
[   21.530026]  [<c018fda4>] do_filp_open+0x184/0x7a0
[   21.530026]  [<c01168e9>] ? kernel_map_pages+0xb9/0x140
[   21.530026]  [<c018068b>] ? poison_obj+0x2b/0x50
[   21.530026]  [<c011b82b>] ? sub_preempt_count+0x4b/0x70
[   21.530026]  [<c05d1efc>] ? _spin_unlock+0x2c/0x50
[   21.530026]  [<c01830aa>] do_sys_open+0x4a/0xb0
[   21.530026]  [<c0288a8c>] ? trace_hardirqs_on_thunk+0xc/0x10
[   21.530026]  [<c018317e>] sys_open+0x2e/0x40
[   21.530026]  [<c010330e>] syscall_call+0x7/0xb
[   21.530026]  =======================
[   36.921087] EXT3 FS on sda1, internal journal
[   38.441628] kjournald starting.  Commit interval 5 seconds
[   38.441628] EXT3 FS on sda5, internal journal
[   38.511628] EXT3-fs: mounted filesystem with ordered data mode.
[   41.510014] PM: Removing info for No Bus:vcs1
[   41.521496] PM: Removing info for No Bus:vcsa1
[   41.581496] PM: Adding info for No Bus:vcs1
[   41.590045] PM: Adding info for No Bus:vcsa1
[   41.590045] PM: Removing info for No Bus:vcs1
[   41.590045] PM: Removing info for No Bus:vcsa1
[   41.603425] PM: Adding info for No Bus:vcs1
[   41.603425] PM: Adding info for No Bus:vcsa1
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