Heh, look what it does... 4====================================================== 4WARNING: possible circular locking dependency detected 4.13.0-rc2-00317-gadc6764a3adf-dirty #797 Tainted: G W 4------------------------------------------------------ 4startpar/582 is trying to acquire lock: c (c(complete)&barr->donec){+.+.}c, at: [<ffffffff8110de4d>] flush_work+0x1fd/0x2c0 4 but task is already holding lock: c (clockc#3c){+.+.}c, at: [<ffffffff8122e866>] lru_add_drain_all_cpuslocked+0x46/0x1a0 4 which lock already depends on the new lock. 4 the existing dependency chain (in reverse order) is: -> #4c (clockc#3c){+.+.}c: __lock_acquire+0x10a5/0x1100 lock_acquire+0xea/0x1f0 __mutex_lock+0x6c/0x960 mutex_lock_nested+0x1b/0x20 lru_add_drain_all_cpuslocked+0x46/0x1a0 lru_add_drain_all+0x13/0x20 SyS_mlockall+0xb8/0x1c0 entry_SYSCALL_64_fastpath+0x23/0xc2 -> #3c (ccpu_hotplug_lock.rw_semc){++++}c: __lock_acquire+0x10a5/0x1100 lock_acquire+0xea/0x1f0 cpus_read_lock+0x2a/0x90 kmem_cache_create+0x2a/0x1d0 scsi_init_sense_cache+0xa0/0xc0 scsi_add_host_with_dma+0x67/0x360 isci_pci_probe+0x873/0xc90 local_pci_probe+0x42/0xa0 work_for_cpu_fn+0x14/0x20 process_one_work+0x273/0x6b0 worker_thread+0x21b/0x3f0 kthread+0x147/0x180 ret_from_fork+0x2a/0x40 -> #2c (cscsi_sense_cache_mutexc){+.+.}c: __lock_acquire+0x10a5/0x1100 lock_acquire+0xea/0x1f0 __mutex_lock+0x6c/0x960 mutex_lock_nested+0x1b/0x20 scsi_init_sense_cache+0x3d/0xc0 scsi_add_host_with_dma+0x67/0x360 isci_pci_probe+0x873/0xc90 local_pci_probe+0x42/0xa0 work_for_cpu_fn+0x14/0x20 process_one_work+0x273/0x6b0 worker_thread+0x21b/0x3f0 kthread+0x147/0x180 ret_from_fork+0x2a/0x40 -> #1c (c(&wfc.work)c){+.+.}c: process_one_work+0x244/0x6b0 worker_thread+0x21b/0x3f0 kthread+0x147/0x180 ret_from_fork+0x2a/0x40 0xffffffffffffffff -> #0c (c(complete)&barr->donec){+.+.}c: check_prev_add+0x3be/0x700 __lock_acquire+0x10a5/0x1100 lock_acquire+0xea/0x1f0 wait_for_completion+0x3b/0x130 flush_work+0x1fd/0x2c0 lru_add_drain_all_cpuslocked+0x158/0x1a0 lru_add_drain_all+0x13/0x20 SyS_mlockall+0xb8/0x1c0 entry_SYSCALL_64_fastpath+0x23/0xc2 other info that might help us debug this: Chain exists of: c(complete)&barr->donec --> ccpu_hotplug_lock.rw_semc --> clockc#3c Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(clockc#3c); lock(ccpu_hotplug_lock.rw_semc); lock(clockc#3c); lock(c(complete)&barr->donec); *** DEADLOCK *** 2 locks held by startpar/582: #0: c (ccpu_hotplug_lock.rw_semc){++++}c, at: [<ffffffff8122e9ce>] lru_add_drain_all+0xe/0x20 #1: c (clockc#3c){+.+.}c, at: [<ffffffff8122e866>] lru_add_drain_all_cpuslocked+0x46/0x1a0 stack backtrace: dCPU: 23 PID: 582 Comm: startpar Tainted: G W 4.13.0-rc2-00317-gadc6764a3adf-dirty #797 dHardware name: Intel Corporation S2600GZ/S2600GZ, BIOS SE5C600.86B.02.02.0002.122320131210 12/23/2013 dCall Trace: d dump_stack+0x86/0xcf d print_circular_bug+0x203/0x2f0 d check_prev_add+0x3be/0x700 d ? add_lock_to_list.isra.30+0xc0/0xc0 d ? is_bpf_text_address+0x82/0xe0 d ? unwind_get_return_address+0x1f/0x30 d __lock_acquire+0x10a5/0x1100 d ? __lock_acquire+0x10a5/0x1100 d ? add_lock_to_list.isra.30+0xc0/0xc0 d lock_acquire+0xea/0x1f0 d ? flush_work+0x1fd/0x2c0 d wait_for_completion+0x3b/0x130 d ? flush_work+0x1fd/0x2c0 d flush_work+0x1fd/0x2c0 d ? flush_workqueue_prep_pwqs+0x1c0/0x1c0 d ? trace_hardirqs_on+0xd/0x10 d lru_add_drain_all_cpuslocked+0x158/0x1a0 d lru_add_drain_all+0x13/0x20 d SyS_mlockall+0xb8/0x1c0 d entry_SYSCALL_64_fastpath+0x23/0xc2 dRIP: 0033:0x7f818d2e54c7 dRSP: 002b:00007fffcce83798 EFLAGS: 00000246c ORIG_RAX: 0000000000000097 dRAX: ffffffffffffffda RBX: 0000000000000046 RCX: 00007f818d2e54c7 dRDX: 0000000000000000 RSI: 00007fffcce83650 RDI: 0000000000000003 dRBP: 000000000002c010 R08: 0000000000000000 R09: 0000000000000000 dR10: 0000000000000008 R11: 0000000000000246 R12: 000000000002d000 dR13: 000000000002c010 R14: 0000000000001000 R15: 00007f818d599b00 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>