INFO: task syz-executor.5:2115 blocked for more than 140 seconds. Not tainted 4.9.171+ #49 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D25112 2115 1 0x00000004 ffff8801d21a2f80 0000000000000000 ffff8801db721000 ffff8801da6f2f80 ffff8801db721018 ffff8801b160f988 ffffffff82801dde ffffffff8281197a 0000000000000000 00ffffff842cb608 ffff8801db7218f0 1ffff100362c1f20 Call Trace: [<0000000066984f73>] schedule+0x92/0x1c0 kernel/sched/core.c:3546 [<00000000b16d8e19>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579 [<00000000e04e474b>] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [<00000000e04e474b>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621 [<000000004399f7ed>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189 [<0000000040aa8496>] loop_reread_partitions+0x7c/0x90 drivers/block/loop.c:638 [<000000008e3a30e2>] loop_clr_fd+0x7dd/0xa60 drivers/block/loop.c:1082 [<00000000d5e8d4b5>] lo_ioctl+0x7b6/0x1a10 drivers/block/loop.c:1415 [<00000000519c9afa>] __blkdev_driver_ioctl block/ioctl.c:294 [inline] [<00000000519c9afa>] blkdev_ioctl+0xe14/0x19e0 block/ioctl.c:590 [<00000000e22a6b78>] block_ioctl+0xde/0x120 fs/block_dev.c:1696 [<0000000097928854>] vfs_ioctl fs/ioctl.c:43 [inline] [<0000000097928854>] file_ioctl fs/ioctl.c:493 [inline] [<0000000097928854>] do_vfs_ioctl+0xb87/0x11d0 fs/ioctl.c:677 [<00000000e080f059>] SYSC_ioctl fs/ioctl.c:694 [inline] [<00000000e080f059>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685 [<000000009bed1a97>] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 [<000000004e230f72>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Showing all locks held in the system: 2 locks held by khungtaskd/24: #0: (rcu_read_lock){......}, at: [<00000000b4158cac>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline] #0: (rcu_read_lock){......}, at: [<00000000b4158cac>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263 #1: (tasklist_lock){.+.+..}, at: [<0000000008f99a5d>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336 2 locks held by getty/2033: #0: (&tty->ldisc_sem){++++++}, at: [<000000008d47ac62>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+...}, at: [<00000000faa0982f>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156 2 locks held by syz-executor.5/2115: #0: (loop_ctl_mutex/1){+.+.+.}, at: [<000000005430fd3d>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405 #1: (&bdev->bd_mutex){+.+.+.}, at: [<000000004399f7ed>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189 1 lock held by syz-executor.3/2120: #0: (&bdev->bd_mutex){+.+.+.}, at: [<000000007ac5de8f>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 2 locks held by syz-executor.0/2123: #0: (&bdev->bd_mutex){+.+.+.}, at: [<000000007ac5de8f>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<0000000064bffb72>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 1 lock held by syz-executor.2/2128: #0: (&bdev->bd_mutex){+.+.+.}, at: [<000000007ac5de8f>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 2 locks held by syz-executor.1/2133: #0: (&bdev->bd_mutex){+.+.+.}, at: [<000000007ac5de8f>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<0000000064bffb72>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 2 locks held by syz-executor.4/2146: #0: (&bdev->bd_mutex){+.+.+.}, at: [<000000007ac5de8f>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<0000000064bffb72>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 2 locks held by blkid/29599: #0: (&bdev->bd_mutex){+.+.+.}, at: [<000000007ac5de8f>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<0000000064bffb72>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 3 locks held by blkid/29600: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000ee59c7da>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1587 #1: (loop_index_mutex){+.+.+.}, at: [<00000000bb71b897>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1664 #2: (loop_ctl_mutex#2){+.+.+.}, at: [<00000000e7f24a37>] __lo_release drivers/block/loop.c:1642 [inline] #2: (loop_ctl_mutex#2){+.+.+.}, at: [<00000000e7f24a37>] lo_release+0x84/0x1b0 drivers/block/loop.c:1665 2 locks held by blkid/29601: #0: (&bdev->bd_mutex){+.+.+.}, at: [<000000007ac5de8f>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<0000000064bffb72>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.171+ #49 ffff8801d98d7cc8 ffffffff81b4fb61 0000000000000001 0000000000000000 0000000000000001 ffffffff81097501 dffffc0000000000 ffff8801d98d7d00 ffffffff81b5adfc 0000000000000001 0000000000000000 0000000000000001 Call Trace: [<000000005bb9d378>] __dump_stack lib/dump_stack.c:15 [inline] [<000000005bb9d378>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<000000000f9c60f1>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99 [<0000000020a99085>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60 [<00000000fa154dfe>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [<000000002465c27c>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [<000000002465c27c>] check_hung_task kernel/hung_task.c:126 [inline] [<000000002465c27c>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline] [<000000002465c27c>] watchdog+0x670/0xaf0 kernel/hung_task.c:263 [<000000004c786cc5>] kthread+0x278/0x310 kernel/kthread.c:211 [<00000000ca22e9c6>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 3 Comm: kworker/0:0 Not tainted 4.9.171+ #49 Workqueue: events_power_efficient gc_workerc task: 0000000077d7f1e8 task.stack: 0000000047b3fadd RIP: 0010:[] c [<00000000b57a6faf>] separate_irq_context kernel/locking/lockdep.c:2988 [inline] RIP: 0010:[] c [<00000000b57a6faf>] __lock_acquire+0x6e8/0x4350 kernel/locking/lockdep.c:3336 RSP: 0000:ffff8801da667960 EFLAGS: 00000806 RAX: 0000000000000000 RBX: 0000000000000251 RCX: ffff8801da603830 RDX: 1ffff1003b4c0714 RSI: ffff8801da6038a8 RDI: ffff8801da6038a1 RBP: ffff8801da667ae8 R08: 0000000000000001 R09: ffff8801da6038c8 R10: ffff8801da6038a8 R11: 0000000000000000 R12: 411f747e01dc507d R13: 0000000000000251 R14: ffff8801da603880 R15: ffff8801da602f80 FS: 0000000000000000(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c423adb010 CR3: 00000001cacf5000 CR4: 00000000001606b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff812080d0c 0000000000000000c 0000000000000000c 000000000000001cc 0000000000000000c ffff8801da602f80c ffff880100000000c 0000000000000002c 0000000000000001c 0000000000000250c 0000000000000001c ffffffff83cae180c Call Trace: [<0000000079cc6577>] lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3756 [<00000000f7d99404>] seqcount_lockdep_reader_access include/linux/seqlock.h:80 [inline] [<00000000f7d99404>] read_seqcount_begin include/linux/seqlock.h:163 [inline] [<00000000f7d99404>] nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:325 [inline] [<00000000f7d99404>] gc_worker+0x11d/0x600 net/netfilter/nf_conntrack_core.c:987 [<0000000096511f0e>] process_one_work+0x88b/0x1600 kernel/workqueue.c:2114 [<000000003c1892a6>] worker_thread+0x5df/0x11d0 kernel/workqueue.c:2251 [<000000004c786cc5>] kthread+0x278/0x310 kernel/kthread.c:211 [<00000000ca22e9c6>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Code: c7a c48 c8b c8c c24 c88 c00 c00 c00 c48 c8d c04 c80 c4c c8d c74 cc1 cd8 c48 cb8 c00 c00 c00 c00 c00 cfc cff cdf c49 c8d c7e c21 c48 c89 cfa c48 cc1 cea c03 c0f cb6 c04 c02 c<48> c89 cfa c83 ce2 c07 c38 cd0 c7f c08 c84 cc0 c0f c85 c72 c2c c00 c00 c49 c8d c7a c