[PATCH 3.2 115/152] Fix circular locking dependency (3.3-rc2)
3.2.67-rc1 review patch. If anyone has any objections, please let me know.
--
From: Ming Lei
commit 864533ceb6db336dead389577c102a8b792a121a upstream.
Hi,
On Wed, Feb 8, 2012 at 8:41 PM, Felipe Balbi wrote:
> Hi guys,
>
> I have just triggered the folllowing:
>
> [ 84.860321] ==
> [ 84.860321] [ INFO: possible circular locking dependency detected ]
> [ 84.860321] 3.3.0-rc2-00026-ge4e8a39 #474 Not tainted
> [ 84.860321] ---
> [ 84.860321] bash/949 is trying to acquire lock:
> [ 84.860321] (sysfs_lock){+.+.+.}, at: []
> gpio_value_store+0x24/0xcc
> [ 84.860321]
> [ 84.860321] but task is already holding lock:
> [ 84.860321] (s_active#22){.+}, at: []
> sysfs_write_file+0xdc/0x184
> [ 84.911468]
> [ 84.911468] which lock already depends on the new lock.
> [ 84.911468]
> [ 84.920043]
> [ 84.920043] the existing dependency chain (in reverse order) is:
> [ 84.920043]
> [ 84.927886] -> #1 (s_active#22){.+}:
> [ 84.927886] [] check_prevs_add+0xdc/0x150
> [ 84.927886] [] validate_chain.clone.24+0x564/0x694
> [ 84.927886] [] __lock_acquire+0x49c/0x980
> [ 84.951660] [] lock_acquire+0x98/0x100
> [ 84.951660] [] sysfs_deactivate+0xb0/0x100
> [ 84.962982] [] sysfs_addrm_finish+0x2c/0x6c
> [ 84.962982] [] sysfs_remove_dir+0x84/0x98
> [ 84.962982] [] kobject_del+0x10/0x78
> [ 84.974670] [] device_del+0x140/0x170
> [ 84.974670] [] device_unregister+0xc/0x18
> [ 84.985382] [] gpio_unexport+0xbc/0xdc
> [ 84.985382] [] gpio_free+0x14/0xfc
> [ 85.001708] [] unexport_store+0x78/0x8c
> [ 85.001708] [] class_attr_store+0x18/0x24
> [ 85.007293] [] sysfs_write_file+0x100/0x184
> [ 85.018981] [] vfs_write+0xb4/0x148
> [ 85.018981] [] sys_write+0x40/0x70
> [ 85.018981] [] ret_fast_syscall+0x0/0x3c
> [ 85.035003]
> [ 85.035003] -> #0 (sysfs_lock){+.+.+.}:
> [ 85.035003] [] check_prev_add+0x680/0x698
> [ 85.035003] [] check_prevs_add+0xdc/0x150
> [ 85.052093] [] validate_chain.clone.24+0x564/0x694
> [ 85.052093] [] __lock_acquire+0x49c/0x980
> [ 85.052093] [] lock_acquire+0x98/0x100
> [ 85.069885] [] mutex_lock_nested+0x3c/0x2f4
> [ 85.069885] [] gpio_value_store+0x24/0xcc
> [ 85.069885] [] dev_attr_store+0x18/0x24
> [ 85.087158] [] sysfs_write_file+0x100/0x184
> [ 85.087158] [] vfs_write+0xb4/0x148
> [ 85.098297] [] sys_write+0x40/0x70
> [ 85.098297] [] ret_fast_syscall+0x0/0x3c
> [ 85.109069]
> [ 85.109069] other info that might help us debug this:
> [ 85.109069]
> [ 85.117462] Possible unsafe locking scenario:
> [ 85.117462]
> [ 85.117462] CPU0 CPU1
> [ 85.128417]
> [ 85.128417] lock(s_active#22);
> [ 85.128417] lock(sysfs_lock);
> [ 85.128417] lock(s_active#22);
> [ 85.142486] lock(sysfs_lock);
> [ 85.151794]
> [ 85.151794] *** DEADLOCK ***
> [ 85.151794]
> [ 85.151794] 2 locks held by bash/949:
> [ 85.158020] #0: (>mutex){+.+.+.}, at: []
> sysfs_write_file+0x28/0x184
> [ 85.170349] #1: (s_active#22){.+}, at: []
> sysfs_write_file+0xdc/0x184
> [ 85.170349]
> [ 85.178588] stack backtrace:
> [ 85.178588] [] (unwind_backtrace+0x0/0xf0) from []
> (print_circular_bug+0x100/0x114)
> [ 85.193023] [] (print_circular_bug+0x100/0x114) from
> [] (check_prev_add+0x680/0x698)
> [ 85.193023] [] (check_prev_add+0x680/0x698) from []
> (check_prevs_add+0xdc/0x150)
> [ 85.212524] [] (check_prevs_add+0xdc/0x150) from []
> (validate_chain.clone.24+0x564/0x694)
> [ 85.212524] [] (validate_chain.clone.24+0x564/0x694) from
> [] (__lock_acquire+0x49c/0x980)
> [ 85.233306] [] (__lock_acquire+0x49c/0x980) from []
> (lock_acquire+0x98/0x100)
> [ 85.233306] [] (lock_acquire+0x98/0x100) from []
> (mutex_lock_nested+0x3c/0x2f4)
> [ 85.242614] [] (mutex_lock_nested+0x3c/0x2f4) from []
> (gpio_value_store+0x24/0xcc)
> [ 85.261840] [] (gpio_value_store+0x24/0xcc) from []
> (dev_attr_store+0x18/0x24)
> [ 85.261840] [] (dev_attr_store+0x18/0x24) from []
> (sysfs_write_file+0x100/0x184)
> [ 85.271240] [] (sysfs_write_file+0x100/0x184) from []
> (vfs_write+0xb4/0x148)
> [ 85.290008] [] (vfs_write+0xb4/0x148) from []
> (sys_write+0x40/0x70)
> [ 85.298400] [] (sys_write+0x40/0x70) from []
> (ret_fast_syscall+0x0/0x3c)
> -bash: echo: write error: Operation not permitted
>
> the way to trigger is:
>
> root@legolas:~# cd /sys/class/gpio/
> root@legolas:/sys/class/gpio# echo 2 > export
> root@legolas:/sys/class/gpio# echo 2 > unexport
> root@legolas:/sys/class/gpio# echo 2 > export
> root@legolas:/sys/class/gpio# cd gpio2/
[PATCH 3.2 115/152] Fix circular locking dependency (3.3-rc2)
3.2.67-rc1 review patch. If anyone has any objections, please let me know.
--
From: Ming Lei tom.leim...@gmail.com
commit 864533ceb6db336dead389577c102a8b792a121a upstream.
Hi,
On Wed, Feb 8, 2012 at 8:41 PM, Felipe Balbi ba...@ti.com wrote:
Hi guys,
I have just triggered the folllowing:
[ 84.860321] ==
[ 84.860321] [ INFO: possible circular locking dependency detected ]
[ 84.860321] 3.3.0-rc2-00026-ge4e8a39 #474 Not tainted
[ 84.860321] ---
[ 84.860321] bash/949 is trying to acquire lock:
[ 84.860321] (sysfs_lock){+.+.+.}, at: [c0275358]
gpio_value_store+0x24/0xcc
[ 84.860321]
[ 84.860321] but task is already holding lock:
[ 84.860321] (s_active#22){.+}, at: [c016996c]
sysfs_write_file+0xdc/0x184
[ 84.911468]
[ 84.911468] which lock already depends on the new lock.
[ 84.911468]
[ 84.920043]
[ 84.920043] the existing dependency chain (in reverse order) is:
[ 84.920043]
[ 84.927886] - #1 (s_active#22){.+}:
[ 84.927886] [c008f640] check_prevs_add+0xdc/0x150
[ 84.927886] [c008fc18] validate_chain.clone.24+0x564/0x694
[ 84.927886] [c0090cdc] __lock_acquire+0x49c/0x980
[ 84.951660] [c0091838] lock_acquire+0x98/0x100
[ 84.951660] [c016a8e8] sysfs_deactivate+0xb0/0x100
[ 84.962982] [c016b1b4] sysfs_addrm_finish+0x2c/0x6c
[ 84.962982] [c016b8bc] sysfs_remove_dir+0x84/0x98
[ 84.962982] [c02590d8] kobject_del+0x10/0x78
[ 84.974670] [c02c29e8] device_del+0x140/0x170
[ 84.974670] [c02c2a24] device_unregister+0xc/0x18
[ 84.985382] [c0276894] gpio_unexport+0xbc/0xdc
[ 84.985382] [c02768c8] gpio_free+0x14/0xfc
[ 85.001708] [c0276a28] unexport_store+0x78/0x8c
[ 85.001708] [c02c5af8] class_attr_store+0x18/0x24
[ 85.007293] [c0169990] sysfs_write_file+0x100/0x184
[ 85.018981] [c0109d48] vfs_write+0xb4/0x148
[ 85.018981] [c0109fd0] sys_write+0x40/0x70
[ 85.018981] [c0013cc0] ret_fast_syscall+0x0/0x3c
[ 85.035003]
[ 85.035003] - #0 (sysfs_lock){+.+.+.}:
[ 85.035003] [c008f54c] check_prev_add+0x680/0x698
[ 85.035003] [c008f640] check_prevs_add+0xdc/0x150
[ 85.052093] [c008fc18] validate_chain.clone.24+0x564/0x694
[ 85.052093] [c0090cdc] __lock_acquire+0x49c/0x980
[ 85.052093] [c0091838] lock_acquire+0x98/0x100
[ 85.069885] [c047e280] mutex_lock_nested+0x3c/0x2f4
[ 85.069885] [c0275358] gpio_value_store+0x24/0xcc
[ 85.069885] [c02c18dc] dev_attr_store+0x18/0x24
[ 85.087158] [c0169990] sysfs_write_file+0x100/0x184
[ 85.087158] [c0109d48] vfs_write+0xb4/0x148
[ 85.098297] [c0109fd0] sys_write+0x40/0x70
[ 85.098297] [c0013cc0] ret_fast_syscall+0x0/0x3c
[ 85.109069]
[ 85.109069] other info that might help us debug this:
[ 85.109069]
[ 85.117462] Possible unsafe locking scenario:
[ 85.117462]
[ 85.117462] CPU0 CPU1
[ 85.128417]
[ 85.128417] lock(s_active#22);
[ 85.128417] lock(sysfs_lock);
[ 85.128417] lock(s_active#22);
[ 85.142486] lock(sysfs_lock);
[ 85.151794]
[ 85.151794] *** DEADLOCK ***
[ 85.151794]
[ 85.151794] 2 locks held by bash/949:
[ 85.158020] #0: (buffer-mutex){+.+.+.}, at: [c01698b8]
sysfs_write_file+0x28/0x184
[ 85.170349] #1: (s_active#22){.+}, at: [c016996c]
sysfs_write_file+0xdc/0x184
[ 85.170349]
[ 85.178588] stack backtrace:
[ 85.178588] [c001b824] (unwind_backtrace+0x0/0xf0) from [c008de64]
(print_circular_bug+0x100/0x114)
[ 85.193023] [c008de64] (print_circular_bug+0x100/0x114) from
[c008f54c] (check_prev_add+0x680/0x698)
[ 85.193023] [c008f54c] (check_prev_add+0x680/0x698) from [c008f640]
(check_prevs_add+0xdc/0x150)
[ 85.212524] [c008f640] (check_prevs_add+0xdc/0x150) from [c008fc18]
(validate_chain.clone.24+0x564/0x694)
[ 85.212524] [c008fc18] (validate_chain.clone.24+0x564/0x694) from
[c0090cdc] (__lock_acquire+0x49c/0x980)
[ 85.233306] [c0090cdc] (__lock_acquire+0x49c/0x980) from [c0091838]
(lock_acquire+0x98/0x100)
[ 85.233306] [c0091838] (lock_acquire+0x98/0x100) from [c047e280]
(mutex_lock_nested+0x3c/0x2f4)
[ 85.242614] [c047e280] (mutex_lock_nested+0x3c/0x2f4) from [c0275358]
(gpio_value_store+0x24/0xcc)
[ 85.261840] [c0275358] (gpio_value_store+0x24/0xcc) from [c02c18dc]
(dev_attr_store+0x18/0x24)
[ 85.261840] [c02c18dc] (dev_attr_store+0x18/0x24) from [c0169990]
(sysfs_write_file+0x100/0x184)
[ 85.271240] [c0169990] (sysfs_write_file+0x100/0x184) from [c0109d48]
(vfs_write+0xb4/0x148)
[ 85.290008] [c0109d48] (vfs_write+0xb4/0x148) from [c0109fd0]
