FYI, we noticed the below changes on git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master commit 2a3e4086f8ea51e0825b5eddc6f0f2623193a428 ("Bluetooth: Unwind l2cap_sock_shutdown()") +----------------------------------------------------+------------+------------+ > | ccf76154d8 | 2a3e4086f8 | +----------------------------------------------------+------------+------------+ > boot_successes | 21 | 19 | > boot_failures | 4 | 22 | > Out_of_memory:Kill_process | 4 | 9 | > INFO:possible_circular_locking_dependency_detected | 0 | 21 | > backtrace:rfcomm_run | 0 | 21 | +----------------------------------------------------+------------+------------+ [ 10.385588] ====================================================== [ 10.386400] [ INFO: possible circular locking dependency detected ] [ 10.387216] 4.1.0-12272-g2a3e408 #1 Not tainted [ 10.387862] ------------------------------------------------------- [ 10.388687] krfcommd/220 is trying to acquire lock: [ 10.389368] (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+...}, at: [] lock_sock+0xb/0xd [ 10.390891] [ 10.390891] but task is already holding lock: [ 10.391789] (&chan->lock/2){+.+...}, at: [] l2cap_chan_lock+0x13/0x15 [ 10.393258] [ 10.393258] which lock already depends on the new lock. [ 10.393258] [ 10.394508] [ 10.394508] the existing dependency chain (in reverse order) is: [ 10.395568] -> #1 (&chan->lock/2){+.+...}: [ 10.396642] [] lock_acquire+0x110/0x19c [ 10.397511] [] mutex_lock_nested+0x6b/0x3a0 [ 10.398414] [] l2cap_chan_lock+0x13/0x15 [ 10.399283] [] l2cap_sock_shutdown+0x91/0x2f4 [ 10.400203] [] l2cap_sock_release+0x40/0x8b [ 10.401106] [] sock_release+0x1f/0x7a [ 10.401954] [] rfcomm_session_del+0x2d/0x49 [ 10.402854] [] rfcomm_run+0x603/0x61c [ 10.403701] [] kthread+0xe0/0xe8 [ 10.404508] [] ret_from_fork+0x3f/0x70 [ 10.405363] -> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+...}: [ 10.406551] [] __lock_acquire+0xc1a/0xf15 [ 10.407437] [] lock_acquire+0x110/0x19c [ 10.408305] [] lock_sock_nested+0x7d/0x9b [ 10.409181] [] lock_sock+0xb/0xd [ 10.409986] [] l2cap_sock_shutdown+0x26e/0x2f4 [ 10.410911] [] l2cap_sock_release+0x40/0x8b [ 10.412231] [] sock_release+0x1f/0x7a [ 10.413790] [] rfcomm_session_del+0x2d/0x49 [ 10.415442] [] rfcomm_run+0x603/0x61c [ 10.417001] [] kthread+0xe0/0xe8 [ 10.418516] [] ret_from_fork+0x3f/0x70 [ 10.420089] [ 10.420089] other info that might help us debug this: [ 10.420089] [ 10.422360] Possible unsafe locking scenario: [ 10.422360] [ 10.424011] CPU0 CPU1 [ 10.443069] ---- ---- [ 10.444123] lock(&chan->lock/2); [ 10.445485] lock(sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP); [ 10.447742] lock(&chan->lock/2); [ 10.449588] lock(sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP); [ 10.451152] [ 10.451152] *** DEADLOCK *** [ 10.451152] [ 10.453031] 1 lock held by krfcommd/220: [ 10.454104] #0: (&chan->lock/2){+.+...}, at: [] l2cap_chan_lock+0x13/0x15 [ 10.456993] [ 10.456993] stack backtrace: [ 10.458366] CPU: 1 PID: 220 Comm: krfcommd Not tainted 4.1.0-12272-g2a3e408 #1 [ 10.460253] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 [ 10.462746] ffffffff8510cb10 ffff8800140a3aa8 ffffffff82e4cf86 ffffffff81121ec6 [ 10.465167] ffffffff8510cb10 ffff8800140a3af8 ffffffff82e45287 ffff8800140a3ac8 [ 10.467663] ffff88001409c140 ffff88001409ce80 ffff88001409c140 ffff88001409ce80 [ 10.470091] Call Trace: [ 10.470885] [] dump_stack+0x4c/0x65 [ 10.472185] [] ? console_unlock+0x3fe/0x42d [ 10.473631] [] print_circular_bug+0x1f8/0x209 [ 10.475038] [] __lock_acquire+0xc1a/0xf15 [ 10.476302] [] ? mark_held_locks+0x52/0x68 [ 10.477814] [] lock_acquire+0x110/0x19c [ 10.479177] [] ? lock_sock+0xb/0xd [ 10.480545] [] lock_sock_nested+0x7d/0x9b [ 10.481988] [] ? lock_sock+0xb/0xd [ 10.483278] [] lock_sock+0xb/0xd [ 10.484025] [] l2cap_sock_shutdown+0x26e/0x2f4 [ 10.484833] [] ? rfcomm_process_rx+0xa3f/0xa3f [ 10.485645] [] ? _raw_write_unlock+0x28/0x33 [ 10.486462] [] ? rfcomm_process_rx+0xa3f/0xa3f [ 10.487259] [] l2cap_sock_release+0x40/0x8b [ 10.488073] [] ? rfcomm_process_rx+0xa3f/0xa3f [ 10.488884] [] sock_release+0x1f/0x7a [ 10.489605] [] rfcomm_session_del+0x2d/0x49 [ 10.490404] [] rfcomm_run+0x603/0x61c [ 10.491123] [] ? abort_exclusive_wait+0xa2/0xa2 [ 10.492082] [] ? rfcomm_process_rx+0xa3f/0xa3f [ 10.492979] [] kthread+0xe0/0xe8 [ 10.493662] [] ? _raw_spin_unlock_irq+0x32/0x3d [ 10.494499] [] ? __wait_for_common+0x42/0x16c [ 10.495286] [] ? __kthread_parkme+0xad/0xad [ 10.496103] [] ret_from_fork+0x3f/0x70 [ 10.496841] [] ? __kthread_parkme+0xad/0xad [ 10.497812] Bluetooth: BNEP (Ethernet Emulation) ver 1.3 Thanks, Ying Huang ------------------------------------- lkp@eclists.intel.com https://eclists.intel.com/sympa/info/lkp Unsubscribe by sending email to sympa@eclists.intel.com with subject "Unsubscribe lkp"