Re: 3.4+ tty lockdep trace

[Sasha Levin <levinsasha928@xxxxxxxxx>]

On Thu, May 24, 2012 at 1:10 PM, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote:
>> I'm still seeing the warning with this patch:
>
> Can you attach the trace that went with the trigger as well ?

Ofcourse, attached as a file.

[   36.332022] ======================================================
[   36.333749] [ INFO: possible circular locking dependency detected ]
[   36.333749] 3.4.0-next-20120524-sasha-00002-g11dc651 #273 Tainted: G        W   
[   36.333749] -------------------------------------------------------
[   36.333749] trinity/4980 is trying to acquire lock:
[   36.333749]  (&tty->legacy_mutex){+.+.+.}, at: [<ffffffff82f71fdb>] tty_lock_nested+0x7b/0x90
[   36.333749] 
[   36.333749] but task is already holding lock:
[   36.333749]  (&tty->legacy_mutex/1){+.+...}, at: [<ffffffff82f71fdb>] tty_lock_nested+0x7b/0x90
[   36.333749] 
[   36.333749] which lock already depends on the new lock.
[   36.333749] 
[   36.333749] 
[   36.333749] the existing dependency chain (in reverse order) is:
[   36.333749] 
[   36.333749] -> #1 (&tty->legacy_mutex/1){+.+...}:
[   36.333749]        [<ffffffff8114a23e>] validate_chain+0x69e/0x790
[   36.333749]        [<ffffffff8114a753>] __lock_acquire+0x423/0x4c0
[   36.333749]        [<ffffffff8114a97a>] lock_acquire+0x18a/0x1e0
[   36.333749]        [<ffffffff82f6e410>] __mutex_lock_common+0x60/0x590
[   36.333749]        [<ffffffff82f6ea70>] mutex_lock_nested+0x40/0x50
[   36.333749]        [<ffffffff82f71fdb>] tty_lock_nested+0x7b/0x90
[   36.333749]        [<ffffffff82f7202e>] tty_lock_pair+0x2e/0x70
[   36.333749]        [<ffffffff81b0f962>] tty_release+0x182/0x4d0
[   36.333749]        [<ffffffff81232d4a>] __fput+0x11a/0x2c0
[   36.333749]        [<ffffffff81232f05>] fput+0x15/0x20
[   36.333749]        [<ffffffff8122f212>] filp_close+0x82/0xa0
[   36.333749]        [<ffffffff810d6514>] close_files+0x1b4/0x200
[   36.333749]        [<ffffffff810d6581>] put_files_struct+0x21/0x180
[   36.333749]        [<ffffffff810d672d>] exit_files+0x4d/0x60
[   36.333749]        [<ffffffff810d89f2>] do_exit+0x322/0x510
[   36.333749]        [<ffffffff810d8c81>] do_group_exit+0xa1/0xe0
[   36.333749]        [<ffffffff810ed5b8>] get_signal_to_deliver+0x4f8/0x580
[   36.333749]        [<ffffffff81065ae2>] do_signal+0x42/0x120
[   36.402106]        [<ffffffff81065c14>] do_notify_resume+0x54/0xb0
[   36.402106]        [<ffffffff82f723bb>] retint_signal+0x4d/0x92
[   36.402106] 
[   36.402106] -> #0 (&tty->legacy_mutex){+.+.+.}:
[   36.402106]        [<ffffffff811497ef>] check_prev_add+0x11f/0x4d0
[   36.402106]        [<ffffffff8114a23e>] validate_chain+0x69e/0x790
[   36.402106]        [<ffffffff8114a753>] __lock_acquire+0x423/0x4c0
[   36.402106]        [<ffffffff8114a97a>] lock_acquire+0x18a/0x1e0
[   36.402106]        [<ffffffff82f6e410>] __mutex_lock_common+0x60/0x590
[   36.402106]        [<ffffffff82f6ea70>] mutex_lock_nested+0x40/0x50
[   36.402106]        [<ffffffff82f71fdb>] tty_lock_nested+0x7b/0x90
[   36.402106]        [<ffffffff82f71ffb>] tty_lock+0xb/0x10
[   36.402106]        [<ffffffff81b155f7>] tty_ldisc_release+0x47/0xb0
[   36.402106]        [<ffffffff81b0fc33>] tty_release+0x453/0x4d0
[   36.402106]        [<ffffffff81232d4a>] __fput+0x11a/0x2c0
[   36.402106]        [<ffffffff81232f05>] fput+0x15/0x20
[   36.402106]        [<ffffffff8122f212>] filp_close+0x82/0xa0
[   36.402106]        [<ffffffff810d6514>] close_files+0x1b4/0x200
[   36.402106]        [<ffffffff810d6581>] put_files_struct+0x21/0x180
[   36.402106]        [<ffffffff810d672d>] exit_files+0x4d/0x60
[   36.402106]        [<ffffffff810d89f2>] do_exit+0x322/0x510
[   36.402106]        [<ffffffff810d8c81>] do_group_exit+0xa1/0xe0
[   36.402106]        [<ffffffff810ed5b8>] get_signal_to_deliver+0x4f8/0x580
[   36.402106]        [<ffffffff81065ae2>] do_signal+0x42/0x120
[   36.402106]        [<ffffffff81065c14>] do_notify_resume+0x54/0xb0
[   36.402106]        [<ffffffff82f723bb>] retint_signal+0x4d/0x92
[   36.402106] 
[   36.402106] other info that might help us debug this:
[   36.402106] 
[   36.402106]  Possible unsafe locking scenario:
[   36.402106] 
[   36.402106]        CPU0                    CPU1
[   36.402106]        ----                    ----
[   36.402106]   lock(&tty->legacy_mutex/1);
[   36.402106]                                lock(&tty->legacy_mutex);
[   36.402106]                                lock(&tty->legacy_mutex/1);
[   36.402106]   lock(&tty->legacy_mutex);
[   36.402106] 
[   36.402106]  *** DEADLOCK ***
[   36.402106] 
[   36.402106] 1 lock held by trinity/4980:
[   36.402106]  #0:  (&tty->legacy_mutex/1){+.+...}, at: [<ffffffff82f71fdb>] tty_lock_nested+0x7b/0x90
[   36.402106] 
[   36.402106] stack backtrace:
[   36.402106] Pid: 4980, comm: trinity Tainted: G        W    3.4.0-next-20120524-sasha-00002-g11dc651 #273
[   36.402106] Call Trace:
[   36.402106]  [<ffffffff811477d5>] print_circular_bug+0x105/0x120
[   36.402106]  [<ffffffff811497ef>] check_prev_add+0x11f/0x4d0
[   36.402106]  [<ffffffff8114a23e>] validate_chain+0x69e/0x790
[   36.402106]  [<ffffffff8111a5f8>] ? sched_clock_cpu+0x108/0x120
[   36.402106]  [<ffffffff8114a753>] __lock_acquire+0x423/0x4c0
[   36.402106]  [<ffffffff8114a97a>] lock_acquire+0x18a/0x1e0
[   36.402106]  [<ffffffff82f71fdb>] ? tty_lock_nested+0x7b/0x90
[   36.402106]  [<ffffffff82f6e410>] __mutex_lock_common+0x60/0x590
[   36.402106]  [<ffffffff82f71fdb>] ? tty_lock_nested+0x7b/0x90
[   36.402106]  [<ffffffff8114aea2>] ? __lock_release+0x1c2/0x1e0
[   36.402106]  [<ffffffff810f5240>] ? flush_scheduled_work+0x20/0x20
[   36.402106]  [<ffffffff82f71fdb>] ? tty_lock_nested+0x7b/0x90
[   36.402106]  [<ffffffff82f6ea70>] mutex_lock_nested+0x40/0x50
[   36.402106]  [<ffffffff82f71fdb>] tty_lock_nested+0x7b/0x90
[   36.402106]  [<ffffffff82f71ffb>] tty_lock+0xb/0x10
[   36.402106]  [<ffffffff81b155f7>] tty_ldisc_release+0x47/0xb0
[   36.402106]  [<ffffffff81b0fc33>] tty_release+0x453/0x4d0
[   36.402106]  [<ffffffff812836cb>] ? vfs_lock_file+0x3b/0x40
[   36.402106]  [<ffffffff81232d4a>] __fput+0x11a/0x2c0
[   36.402106]  [<ffffffff81232f05>] fput+0x15/0x20
[   36.402106]  [<ffffffff8122f212>] filp_close+0x82/0xa0
[   36.402106]  [<ffffffff810d6514>] close_files+0x1b4/0x200
[   36.402106]  [<ffffffff810d6360>] ? wait_task_stopped+0x3d0/0x3d0
[   36.402106]  [<ffffffff810d6725>] ? exit_files+0x45/0x60
[   36.402106]  [<ffffffff810d6581>] put_files_struct+0x21/0x180
[   36.402106]  [<ffffffff82f71a10>] ? _raw_spin_unlock+0x30/0x60
[   36.402106]  [<ffffffff810d672d>] exit_files+0x4d/0x60
[   36.402106]  [<ffffffff810d89f2>] do_exit+0x322/0x510
[   36.402106]  [<ffffffff810d8c81>] do_group_exit+0xa1/0xe0
[   36.402106]  [<ffffffff810ed5b8>] get_signal_to_deliver+0x4f8/0x580
[   36.402106]  [<ffffffff81065ae2>] do_signal+0x42/0x120
[   36.402106]  [<ffffffff81090000>] ? create_irq+0x10/0x30
[   36.402106]  [<ffffffff811ee78e>] ? might_fault+0x4e/0xa0
[   36.402106]  [<ffffffff82f7237f>] ? retint_signal+0x11/0x92
[   36.402106]  [<ffffffff81065c14>] do_notify_resume+0x54/0xb0
[   36.402106]  [<ffffffff82f723bb>] retint_signal+0x4d/0x92