INFO: task syz-executor.1:2138 blocked for more than 140 seconds. Not tainted 4.9.170+ #48 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.1 D24856 2138 1 0x00000004 ffff8801ce5997c0 ffff8801a0443180 ffff8801db721000 ffff8801ae2ac740 ffff8801db721018 ffff8801adce7b28 ffffffff82801a4e 0000000041b58ab3 ffff8801adce7aa0 00ffffff81bb61ac ffff8801db7218f0 1ffff10035b9cf54 Call Trace: [<000000005307c0b2>] schedule+0x92/0x1c0 kernel/sched/core.c:3546 [<00000000bc9d4836>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579 [<0000000045bb61c6>] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [<0000000045bb61c6>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621 [<000000006985ed78>] __lo_release drivers/block/loop.c:1642 [inline] [<000000006985ed78>] lo_release+0x84/0x1b0 drivers/block/loop.c:1665 [<0000000001460305>] __blkdev_put+0x461/0x840 fs/block_dev.c:1606 [<00000000c08534ec>] blkdev_put+0x88/0x560 fs/block_dev.c:1671 [<000000008c516a53>] blkdev_close+0x8b/0xb0 fs/block_dev.c:1678 [<00000000403fd163>] __fput+0x274/0x720 fs/file_table.c:208 [<00000000a34615f3>] ____fput+0x16/0x20 fs/file_table.c:244 [<00000000476783e7>] task_work_run+0x108/0x180 kernel/task_work.c:116 [<00000000983bd3db>] tracehook_notify_resume include/linux/tracehook.h:191 [inline] [<00000000983bd3db>] exit_to_usermode_loop+0x13b/0x160 arch/x86/entry/common.c:162 [<000000001fc872f4>] prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] [<000000001fc872f4>] syscall_return_slowpath arch/x86/entry/common.c:263 [inline] [<000000001fc872f4>] do_syscall_64+0x3f7/0x570 arch/x86/entry/common.c:290 [<0000000004003c13>] 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: [<0000000094994606>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline] #0: (rcu_read_lock){......}, at: [<0000000094994606>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263 #1: (tasklist_lock){.+.+..}, at: [<0000000006ce79fb>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4339 2 locks held by getty/2051: #0: (&tty->ldisc_sem){++++++}, at: [<00000000923bb311>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+...}, at: [<00000000632655c6>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156 3 locks held by syz-executor.1/2138: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000c5e7c3de>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1587 #1: (loop_index_mutex){+.+.+.}, at: [<0000000078d959b5>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1664 #2: (loop_ctl_mutex#2){+.+.+.}, at: [<000000006985ed78>] __lo_release drivers/block/loop.c:1642 [inline] #2: (loop_ctl_mutex#2){+.+.+.}, at: [<000000006985ed78>] lo_release+0x84/0x1b0 drivers/block/loop.c:1665 2 locks held by blkid/12756: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000a053bbe1>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<0000000034f542ad>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 2 locks held by syz-executor.4/12760: #0: (loop_ctl_mutex/1){+.+.+.}, at: [<000000004227126d>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405 #1: (&bdev->bd_mutex){+.+.+.}, at: [<00000000d709bf33>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189 1 lock held by blkid/12761: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000a053bbe1>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.170+ #48 ffff8801d98d7cc8 ffffffff81b4fb21 0000000000000001 0000000000000000 0000000000000001 ffffffff81097401 dffffc0000000000 ffff8801d98d7d00 ffffffff81b5adbc 0000000000000001 0000000000000000 0000000000000001 Call Trace: [<0000000090dec1af>] __dump_stack lib/dump_stack.c:15 [inline] [<0000000090dec1af>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<00000000c38d8e96>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99 [<00000000a5405e67>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60 [<00000000bed3e600>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [<00000000a0a7da08>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [<00000000a0a7da08>] check_hung_task kernel/hung_task.c:126 [inline] [<00000000a0a7da08>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline] [<00000000a0a7da08>] watchdog+0x670/0xaf0 kernel/hung_task.c:263 [<00000000bca6060b>] kthread+0x278/0x310 kernel/kthread.c:211 [<000000000e85f695>] 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: 22809 Comm: syz-executor.0 Not tainted 4.9.170+ #48 task: 000000000b3fa0f8 task.stack: 0000000037ec3631 RIP: 0010:[] c [<00000000bfdd2a6c>] mark_irqflags kernel/locking/lockdep.c:2953 [inline] RIP: 0010:[] c [<00000000bfdd2a6c>] __lock_acquire+0x570/0x4350 kernel/locking/lockdep.c:3302 RSP: 0018:ffff880170387bb0 EFLAGS: 00000002 RAX: 0000000000000001 RBX: 0000000000000002 RCX: 1ffff1003aa6a417 RDX: 1ffffffff07956b2 RSI: ffff8801d5352098 RDI: ffffffff83cab590 RBP: ffff880170387d40 R08: 0000000000000001 R09: ffff8801d53520b8 R10: ffff8801d5352098 R11: 1ffff1003aa6a412 R12: 0000000000000001 R13: 0000000000000237 R14: 0000000000000001 R15: ffff8801d53517c0 FS: 00007f1e5dba5700(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1e5da7a000 CR3: 00000001c72a6000 CR4: 00000000001606b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Stack: 0000004000000008c ffff880170387bc8c ffff880170387c00c ffffffff81bb61acc ffffffff814f8750c 000000000002b6e8c 1ffff1002e070f8cc 0000000000000000c ffff880170387c30c ffffffff81bb61acc ffff880170387c10c 000060fe24614e08c Call Trace: [<0000000044419b76>] lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3759 [<000000006037f7d1>] __raw_spin_lock include/linux/spinlock_api_smp.h:144 [inline] [<000000006037f7d1>] _raw_spin_lock+0x38/0x50 kernel/locking/spinlock.c:151 [<000000002011789b>] spin_lock include/linux/spinlock.h:302 [inline] [<000000002011789b>] browse_rb mm/mmap.c:313 [inline] [<000000002011789b>] validate_mm+0x2fe/0x5a0 mm/mmap.c:380 [<00000000373295d4>] remove_vma_list mm/mmap.c:2518 [inline] [<00000000373295d4>] do_munmap+0x702/0xd00 mm/mmap.c:2740 [<00000000f6e1f94b>] SYSC_munmap mm/mmap.c:2768 [inline] [<00000000f6e1f94b>] SyS_munmap+0x74/0xb0 mm/mmap.c:2760 [<00000000c5fc0046>] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 [<0000000004003c13>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Code: c00 c00 c00 c85 cc0 c74 c1d c4c c89 cd6 c4c c89 cff c4c c89 c54 c24 c70 ce8 c14 ce1 cff cff c4c c8b c54 c24 c70 c85 cc0 c0f c84 cf1 c03 c00 c00 c41 c80 c7a c21 c00 c78 c60 c<49> c8d cbf c30 c10 c00 c00 c48 cb8 c00 c00 c00 c00 c00 cfc cff cdf c48 c89 cfa c48 c