INFO: task syz-executor7:7442 blocked for more than 120 seconds. Not tainted 4.16.0-rc6+ #366 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor7 D25792 7442 4237 0x00000004 Call Trace: context_switch kernel/sched/core.c:2862 [inline] __schedule+0x8fb/0x1ec0 kernel/sched/core.c:3440 schedule+0xf5/0x430 kernel/sched/core.c:3499 cgroup_lock_and_drain_offline+0x217/0x670 kernel/cgroup/cgroup.c:2808 cgroup_kn_lock_live+0x320/0x580 kernel/cgroup/cgroup.c:1533 cgroup_subtree_control_write+0x316/0xb00 kernel/cgroup/cgroup.c:3108 cgroup_file_write+0x2ae/0x710 kernel/cgroup/cgroup.c:3429 kernfs_fop_write+0x2bc/0x440 fs/kernfs/file.c:316 __vfs_write+0xef/0x970 fs/read_write.c:480 vfs_write+0x189/0x510 fs/read_write.c:544 SYSC_write fs/read_write.c:589 [inline] SyS_write+0xef/0x220 fs/read_write.c:581 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x454879 RSP: 002b:00007fd735202c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fd7352036d4 RCX: 0000000000454879 RDX: 0000000000000006 RSI: 00000000200000c0 RDI: 0000000000000015 RBP: 000000000072c010 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000067e R14: 00000000006fac70 R15: 0000000000000002 Showing all locks held in the system: 4 locks held by kworker/0:0/3: #0: ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<00000000dffad8ef>] work_static include/linux/workqueue.h:198 [inline] #0: ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<00000000dffad8ef>] set_work_data kernel/workqueue.c:619 [inline] #0: ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<00000000dffad8ef>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<00000000dffad8ef>] process_one_work+0xb12/0x1bb0 kernel/workqueue.c:2084 #1: ((work_completion)(&cw->work)){+.+.}, at: [<000000008b7c0527>] process_one_work+0xb89/0x1bb0 kernel/workqueue.c:2088 #2: (cpu_hotplug_lock.rw_sem){++++}, at: [<00000000cf654026>] get_online_cpus include/linux/cpu.h:124 [inline] #2: (cpu_hotplug_lock.rw_sem){++++}, at: [<00000000cf654026>] memcg_create_kmem_cache+0x16/0x170 mm/slab_common.c:619 #3: (slab_mutex){+.+.}, at: [<00000000eb33d879>] memcg_create_kmem_cache+0x24/0x170 mm/slab_common.c:622 4 locks held by kworker/1:0/17: #0: ((wq_completion)"cgroup_destroy"){+.+.}, at: [<00000000dffad8ef>] work_static include/linux/workqueue.h:198 [inline] #0: ((wq_completion)"cgroup_destroy"){+.+.}, at: [<00000000dffad8ef>] set_work_data kernel/workqueue.c:619 [inline] #0: ((wq_completion)"cgroup_destroy"){+.+.}, at: [<00000000dffad8ef>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ((wq_completion)"cgroup_destroy"){+.+.}, at: [<00000000dffad8ef>] process_one_work+0xb12/0x1bb0 kernel/workqueue.c:2084 #1: ((work_completion)(&css->destroy_work)#3){+.+.}, at: [<000000008b7c0527>] process_one_work+0xb89/0x1bb0 kernel/workqueue.c:2088 #2: (cpu_hotplug_lock.rw_sem){++++}, at: [<00000000c067a924>] get_online_cpus include/linux/cpu.h:124 [inline] #2: (cpu_hotplug_lock.rw_sem){++++}, at: [<00000000c067a924>] memcg_destroy_kmem_caches+0xf/0x80 mm/slab_common.c:771 #3: (slab_mutex){+.+.}, at: [<0000000058b626fe>] memcg_destroy_kmem_caches+0x24/0x80 mm/slab_common.c:774 4 locks held by kworker/1:1/23: #0: ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<00000000dffad8ef>] work_static include/linux/workqueue.h:198 [inline] #0: ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<00000000dffad8ef>] set_work_data kernel/workqueue.c:619 [inline] #0: ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<00000000dffad8ef>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ((wq_completion)"memcg_kmem_cache"){+.+.}, at: [<00000000dffad8ef>] process_one_work+0xb12/0x1bb0 kernel/workqueue.c:2084 #1: ((work_completion)(&cw->work)){+.+.}, at: [<000000008b7c0527>] process_one_work+0xb89/0x1bb0 kernel/workqueue.c:2088 #2: (cpu_hotplug_lock.rw_sem){++++}, at: [<00000000cf654026>] get_online_cpus include/linux/cpu.h:124 [inline] #2: (cpu_hotplug_lock.rw_sem){++++}, at: [<00000000cf654026>] memcg_create_kmem_cache+0x16/0x170 mm/slab_common.c:619 #3: (slab_mutex){+.+.}, at: [<00000000eb33d879>] memcg_create_kmem_cache+0x24/0x170 mm/slab_common.c:622 2 locks held by khungtaskd/801: #0: (rcu_read_lock){....}, at: [<000000006d144724>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<000000006d144724>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<0000000051fd607c>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470 2 locks held by getty/4157: #0: (&tty->ldisc_sem){++++}, at: [<0000000023771ea7>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000195fc6d2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4158: #0: (&tty->ldisc_sem){++++}, at: [<0000000023771ea7>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000195fc6d2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4159: #0: (&tty->ldisc_sem){++++}, at: [<0000000023771ea7>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000195fc6d2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4160: #0: (&tty->ldisc_sem){++++}, at: [<0000000023771ea7>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000195fc6d2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4161: #0: (&tty->ldisc_sem){++++}, at: [<0000000023771ea7>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000195fc6d2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/4162: #0: (&tty->ldisc_sem){++++}, at: [<0000000023771ea7>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000195fc6d2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 2 locks held by getty/23887: #0: (&tty->ldisc_sem){++++}, at: [<0000000023771ea7>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<00000000195fc6d2>] n_tty_read+0x2ef/0x1a40 drivers/tty/n_tty.c:2131 3 locks held by syz-executor7/7442: #0: (&f->f_pos_lock){+.+.}, at: [<00000000278b79a3>] __fdget_pos+0x12b/0x190 fs/file.c:765 #1: (sb_writers#10){.+.+}, at: [<00000000b21f4955>] file_start_write include/linux/fs.h:2709 [inline] #1: (sb_writers#10){.+.+}, at: [<00000000b21f4955>] vfs_write+0x407/0x510 fs/read_write.c:543 #2: (&of->mutex){+.+.}, at: [<00000000e434432f>] kernfs_fop_write+0x208/0x440 fs/kernfs/file.c:307 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 801 Comm: khungtaskd Not tainted 4.16.0-rc6+ #366 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x24d lib/dump_stack.c:53 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x123/0x180 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline] check_hung_task kernel/hung_task.c:132 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0x90c/0xd60 kernel/hung_task.c:249 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 1894 Comm: kworker/0:3 Not tainted 4.16.0-rc6+ #366 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: cgroup_destroy css_free_work_fn RIP: 0010:qlist_move_cache+0x73/0xf0 mm/kasan/quarantine.c:275 RSP: 0018:ffff8801d1ddf0c8 EFLAGS: 00000082 RAX: ffff8801cec99a80 RBX: 000077ff80000000 RCX: ffff8801cec99a80 RDX: ffff88018fc7d380 RSI: ffff8801d1ddf0e8 RDI: ffffffff885e9b40 RBP: ffff8801d1ddf0d8 R08: ffff8801c3fe1500 R09: 0000000080000000 R10: ffff880179a58a80 R11: ffffea0000000000 R12: ffffea00064b061f R13: ffffffff86fd55a0 R14: ffffffff885ef2a0 R15: ffff88018fc7d380 FS: 0000000000000000(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 0000000006e22004 CR4: 00000000001606f0 DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: quarantine_remove_cache+0x79/0xf0 mm/kasan/quarantine.c:317 kasan_cache_shutdown+0x9/0x10 mm/kasan/kasan.c:381 shutdown_cache+0x15/0x1b0 mm/slab_common.c:577 memcg_destroy_kmem_caches+0x62/0x80 mm/slab_common.c:781 memcg_free_kmem mm/memcontrol.c:2856 [inline] mem_cgroup_css_free+0x2a4/0x3f0 mm/memcontrol.c:4298 css_free_work_fn+0x1c8/0x1420 kernel/cgroup/cgroup.c:4541 process_one_work+0xc47/0x1bb0 kernel/workqueue.c:2113 worker_thread+0x223/0x1990 kernel/workqueue.c:2247 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406 Code: 3f 00 8b 40 14 74 7f 4c 8b 47 08 49 89 08 48 89 4f 08 48 c7 01 00 00 00 00 4c 89 d1 48 01 47 10 4d 85 d2 74 5c 48 89 c8 4c 8b 11 <4c> 01 c8 72 62 49 89 d8 4c 01 c0 48 c1 e8 0c 48 c1 e0 06 4c 01