====================================================== WARNING: possible circular locking dependency detected 4.13.0-rc6-next-20170823+ #7 Not tainted ------------------------------------------------------ kworker/0:2/1336 is trying to acquire lock: ((delayed_fput_work).work){+.+.}, at: [] process_one_work+0xb2c/0x1be0 kernel/workqueue.c:2094 but now in release context of a crosslock acquired at the following: ((complete)&rcu.completion){+.+.}, at: [] __synchronize_srcu+0x1b5/0x250 kernel/rcu/srcutree.c:898 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 ((complete)&rcu.completion){+.+.}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x3286/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 complete_acquire include/linux/completion.h:39 [inline] __wait_for_common kernel/sched/completion.c:108 [inline] wait_for_common kernel/sched/completion.c:122 [inline] wait_for_completion+0xc8/0x770 kernel/sched/completion.c:143 __synchronize_srcu+0x1b5/0x250 kernel/rcu/srcutree.c:898 synchronize_srcu_expedited kernel/rcu/srcutree.c:923 [inline] synchronize_srcu+0x1a3/0x560 kernel/rcu/srcutree.c:974 quarantine_remove_cache+0xd7/0xf0 mm/kasan/quarantine.c:327 kasan_cache_shrink+0x9/0x10 mm/kasan/kasan.c:380 kmem_cache_shrink+0x15/0x30 mm/slab_common.c:857 acpi_os_purge_cache+0x15/0x20 drivers/acpi/osl.c:1560 acpi_purge_cached_objects+0x38/0xc9 drivers/acpi/acpica/utxface.c:271 acpi_initialize_objects+0xc5/0x112 drivers/acpi/acpica/utxfinit.c:302 acpi_bus_init drivers/acpi/bus.c:1131 [inline] acpi_init+0x23c/0x8e6 drivers/acpi/bus.c:1220 do_one_initcall+0x9e/0x330 init/main.c:825 do_initcall_level init/main.c:891 [inline] do_initcalls init/main.c:899 [inline] do_basic_setup init/main.c:917 [inline] kernel_init_freeable+0x46e/0x526 init/main.c:1067 kernel_init+0x13/0x172 init/main.c:992 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 -> #4 (cpu_hotplug_lock.rw_sem){++++}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x3286/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:35 [inline] percpu_down_read include/linux/percpu-rwsem.h:58 [inline] cpus_read_lock+0x42/0x90 kernel/cpu.c:218 get_online_cpus include/linux/cpu.h:126 [inline] kmem_cache_create+0x26/0x2a0 mm/slab_common.c:431 bio_find_or_create_slab block/bio.c:115 [inline] bioset_create+0x42c/0x850 block/bio.c:1981 init_bio+0x193/0x1b6 block/bio.c:2125 do_one_initcall+0x9e/0x330 init/main.c:825 do_initcall_level init/main.c:891 [inline] do_initcalls init/main.c:899 [inline] do_basic_setup init/main.c:917 [inline] kernel_init_freeable+0x46e/0x526 init/main.c:1067 kernel_init+0x13/0x172 init/main.c:992 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 -> #3 (bio_slab_lock){+.+.}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x3286/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1870 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 bio_find_or_create_slab block/bio.c:80 [inline] bioset_create+0x261/0x850 block/bio.c:1981 blk_alloc_queue_node+0x139/0xba0 block/blk-core.c:826 blk_mq_init_queue+0x46/0x90 block/blk-mq.c:2264 loop_add+0x2f0/0x990 drivers/block/loop.c:1796 loop_init+0x1ae/0x20a drivers/block/loop.c:2056 do_one_initcall+0x9e/0x330 init/main.c:825 do_initcall_level init/main.c:891 [inline] do_initcalls init/main.c:899 [inline] do_basic_setup init/main.c:917 [inline] kernel_init_freeable+0x46e/0x526 init/main.c:1067 kernel_init+0x13/0x172 init/main.c:992 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 -> #2 (loop_index_mutex){+.+.}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x3286/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1870 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 lo_open+0x1b/0xa0 drivers/block/loop.c:1586 __blkdev_get+0x2cd/0xf60 fs/block_dev.c:1463 blkdev_get+0x3a1/0xad0 fs/block_dev.c:1600 blkdev_open+0x1ff/0x2c0 fs/block_dev.c:1756 do_dentry_open+0x67f/0xd70 fs/open.c:752 vfs_open+0x107/0x220 fs/open.c:866 do_last fs/namei.c:3388 [inline] path_openat+0x1157/0x3520 fs/namei.c:3528 do_filp_open+0x25b/0x3b0 fs/namei.c:3563 do_sys_open+0x502/0x6d0 fs/open.c:1059 SYSC_open fs/open.c:1077 [inline] SyS_open+0x2d/0x40 fs/open.c:1072 entry_SYSCALL_64_fastpath+0x1f/0xbe -> #1 (&bdev->bd_mutex){+.+.}: check_prevs_add kernel/locking/lockdep.c:2020 [inline] validate_chain kernel/locking/lockdep.c:2469 [inline] __lock_acquire+0x3286/0x4620 kernel/locking/lockdep.c:3498 lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:4002 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1870 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 blkdev_put+0x2a/0x4f0 fs/block_dev.c:1800 blkdev_close+0x91/0xc0 fs/block_dev.c:1849 __fput+0x333/0x7f0 fs/file_table.c:210 delayed_fput+0x44/0x70 fs/file_table.c:240 process_one_work+0xbfd/0x1be0 kernel/workqueue.c:2098 worker_thread+0x223/0x1860 kernel/workqueue.c:2233 kthread+0x39c/0x470 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 -> #0 ((delayed_fput_work).work){+.+.}: process_one_work+0xba5/0x1be0 kernel/workqueue.c:2095 worker_thread+0x223/0x1860 kernel/workqueue.c:2233 kthread+0x39c/0x470 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 0xffffffffffffffff other info that might help us debug this: Chain exists of: (delayed_fput_work).work --> cpu_hotplug_lock.rw_sem --> (complete)&rcu.completion Possible unsafe locking scenario by crosslock: CPU0 CPU1 ---- ---- lock(cpu_hotplug_lock.rw_sem); lock((complete)&rcu.completion); lock((delayed_fput_work).work); unlock((complete)&rcu.completion); *** DEADLOCK *** 3 locks held by kworker/0:2/1336: #0: ("events_power_efficient"){.+.+}, at: [] __write_once_size include/linux/compiler.h:305 [inline] #0: ("events_power_efficient"){.+.+}, at: [] atomic64_set arch/x86/include/asm/atomic64_64.h:33 [inline] #0: ("events_power_efficient"){.+.+}, at: [] atomic_long_set include/asm-generic/atomic-long.h:56 [inline] #0: ("events_power_efficient"){.+.+}, at: [] set_work_data kernel/workqueue.c:617 [inline] #0: ("events_power_efficient"){.+.+}, at: [] set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: ("events_power_efficient"){.+.+}, at: [] process_one_work+0xad4/0x1be0 kernel/workqueue.c:2090 #1: ((&(&sdp->work)->work)){+.+.}, at: [] process_one_work+0xb2c/0x1be0 kernel/workqueue.c:2094 #2: (&x->wait#5){....}, at: [] complete+0x18/0x80 kernel/sched/completion.c:34 stack backtrace: CPU: 0 PID: 1336 Comm: kworker/0:2 Not tainted 4.13.0-rc6-next-20170823+ #7 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: events_power_efficient srcu_invoke_callbacks Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 print_circular_bug+0x503/0x710 kernel/locking/lockdep.c:1259 check_prev_add+0x865/0x1520 kernel/locking/lockdep.c:1894 commit_xhlock kernel/locking/lockdep.c:5002 [inline] commit_xhlocks kernel/locking/lockdep.c:5046 [inline] lock_commit_crosslock+0xe73/0x1d10 kernel/locking/lockdep.c:5085 complete_release_commit include/linux/completion.h:49 [inline] complete+0x24/0x80 kernel/sched/completion.c:39 wakeme_after_rcu+0xd/0x10 kernel/rcu/update.c:376 srcu_invoke_callbacks+0x280/0x4d0 kernel/rcu/srcutree.c:1161 process_one_work+0xbfd/0x1be0 kernel/workqueue.c:2098 worker_thread+0x223/0x1860 kernel/workqueue.c:2233 kthread+0x39c/0x470 kernel/kthread.c:231 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431