[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]