INFO: task syz-executor.2:2118 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.2 D25016 2118 1 0x00000004 ffff8801cfd2df00 ffff8801cb2a7380 ffff8801db721000 ffff8801ca9c0000 ffff8801db721018 ffff8801a7a17b28 ffffffff82801dde 0000000041b58ab3 ffff8801a7a17aa0 00ffffff81bb61ec ffff8801db7218f0 1ffff10034f42f54 Call Trace: [<0000000069d6cc0a>] schedule+0x92/0x1c0 kernel/sched/core.c:3546 [<00000000a0825c21>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579 [<00000000e458b5d5>] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [<00000000e458b5d5>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621 [<0000000073173d24>] __lo_release drivers/block/loop.c:1642 [inline] [<0000000073173d24>] lo_release+0x84/0x1b0 drivers/block/loop.c:1665 [<00000000f6a43057>] __blkdev_put+0x461/0x840 fs/block_dev.c:1606 [<0000000032048980>] blkdev_put+0x88/0x560 fs/block_dev.c:1671 [<000000005261c46b>] blkdev_close+0x8b/0xb0 fs/block_dev.c:1678 [<0000000023df72d4>] __fput+0x274/0x720 fs/file_table.c:208 [<000000009225d6a3>] ____fput+0x16/0x20 fs/file_table.c:244 [<000000005d3736c7>] task_work_run+0x108/0x180 kernel/task_work.c:116 [<00000000069bc0f0>] tracehook_notify_resume include/linux/tracehook.h:191 [inline] [<00000000069bc0f0>] exit_to_usermode_loop+0x13b/0x160 arch/x86/entry/common.c:162 [<000000005a3932a7>] prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] [<000000005a3932a7>] syscall_return_slowpath arch/x86/entry/common.c:263 [inline] [<000000005a3932a7>] do_syscall_64+0x3f7/0x570 arch/x86/entry/common.c:290 [<0000000076fe62b7>] 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: [<000000006133ea00>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline] #0: (rcu_read_lock){......}, at: [<000000006133ea00>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263 #1: (tasklist_lock){.+.+..}, at: [<00000000d875d762>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336 2 locks held by getty/2023: #0: (&tty->ldisc_sem){++++++}, at: [<00000000c30925eb>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+...}, at: [<0000000019e19326>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156 3 locks held by syz-executor.2/2118: #0: (&bdev->bd_mutex){+.+.+.}, at: [<000000003f0b7f81>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1587 #1: (loop_index_mutex){+.+.+.}, at: [<00000000b895ed64>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1664 #2: (loop_ctl_mutex#2){+.+.+.}, at: [<0000000073173d24>] __lo_release drivers/block/loop.c:1642 [inline] #2: (loop_ctl_mutex#2){+.+.+.}, at: [<0000000073173d24>] lo_release+0x84/0x1b0 drivers/block/loop.c:1665 2 locks held by syz-executor.0/11425: #0: (&bdev->bd_mutex){+.+.+.}, at: [<000000002863e513>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<000000001f84505b>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 1 lock held by syz-executor.1/15332: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000e00211a3>] blkdev_put+0x2b/0x560 fs/block_dev.c:1629 2 locks held by syz-executor.4/20620: #0: (&bdev->bd_mutex){+.+.+.}, at: [<000000002863e513>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<000000001f84505b>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 2 locks held by syz-executor.1/21470: #0: (loop_ctl_mutex/1){+.+.+.}, at: [<0000000041c7c2c6>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405 #1: (&bdev->bd_mutex){+.+.+.}, at: [<000000004a11649c>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189 2 locks held by blkid/21473: #0: (&bdev->bd_mutex){+.+.+.}, at: [<000000002863e513>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<000000001f84505b>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 24 Comm: khungtaskd Not tainted 4.9.171+ #49 ffff8801d98d7cc8 ffffffff81b4fb61 0000000000000000 0000000000000000 0000000000000000 ffffffff81097501 dffffc0000000000 ffff8801d98d7d00 ffffffff81b5adfc 0000000000000000 0000000000000000 0000000000000000 Call Trace: [<000000006b4627c2>] __dump_stack lib/dump_stack.c:15 [inline] [<000000006b4627c2>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<000000008d8a7409>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99 [<000000005707c2da>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60 [<0000000037e26f91>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [<0000000092e0438b>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [<0000000092e0438b>] check_hung_task kernel/hung_task.c:126 [inline] [<0000000092e0438b>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline] [<0000000092e0438b>] watchdog+0x670/0xaf0 kernel/hung_task.c:263 [<000000008919343f>] kthread+0x278/0x310 kernel/kthread.c:211 [<00000000f9b0cace>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 15260 Comm: syz-executor.3 Not tainted 4.9.171+ #49 task: 00000000e8bc40c3 task.stack: 000000002950ab69 RIP: 0010:[] c [<00000000356b6f66>] __sanitizer_cov_trace_pc+0x4/0x50 kernel/kcov.c:96 RSP: 0018:ffff8801af037b58 EFLAGS: 00000296 RAX: 0000000000000008 RBX: 0000000000000007 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffffffff81b9bf80 RDI: ffffffff833ed000 RBP: ffff8801af037b58 R08: ffffffff84231508 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000008 R13: 0000000000000002 R14: ffffffff833ed000 R15: dffffc0000000000 FS: 00007f91a9c07700(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6a3dc0f000 CR3: 00000001d6ff9000 CR4: 00000000001606b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Stack: ffff8801af037b80c ffffffff81b9bff4c 00000000000009d7c ffffffff842314a8c fffffbfff067dc2cc ffff8801af037bd8c ffffffff812460fdc ffff8801af037d30c 0000000000000046c 1ffffffff0846295c 00000001cf20b748c fffffbfff067dc2cc Call Trace: [<00000000566e8420>] find_next_bit+0x44/0x50 lib/find_bit.c:64 [<00000000d4b9005e>] cpumask_next include/linux/cpumask.h:195 [inline] [<00000000d4b9005e>] srcu_readers_seq_idx.isra.0+0xbd/0x160 kernel/rcu/srcu.c:153 [<00000000800e7dc6>] srcu_readers_active_idx_check kernel/rcu/srcu.c:190 [inline] [<00000000800e7dc6>] try_check_zero+0x53/0x1d0 kernel/rcu/srcu.c:342 [<000000002087ddaf>] srcu_advance_batches+0x7c/0x430 kernel/rcu/srcu.c:573 [<000000002d44de45>] __synchronize_srcu+0x16d/0x3d0 kernel/rcu/srcu.c:434 [<00000000636437a8>] synchronize_srcu+0x1f/0x40 kernel/rcu/srcu.c:492 [<00000000fa5c6b53>] fsnotify_mark_destroy_list+0x110/0x390 fs/notify/mark.c:551 [<000000006b89e0b2>] fsnotify_destroy_group+0x6b/0x120 fs/notify/group.c:76 [<00000000c0b28c9d>] inotify_new_group fs/notify/inotify/inotify_user.c:660 [inline] [<00000000c0b28c9d>] SYSC_inotify_init1 fs/notify/inotify/inotify_user.c:682 [inline] [<00000000c0b28c9d>] SyS_inotify_init1+0x2be/0x350 fs/notify/inotify/inotify_user.c:669 [<00000000dade9456>] sys_inotify_init+0x10/0x20 fs/notify/inotify/inotify_user.c:696 [<0000000055dce996>] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 [<0000000076fe62b7>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Code: c89 cdf ce8 c70 cbc c1d c00 ce9 c9a cfe cff cff c4c c89 cef ce8 c63 cbc c1d c00 ce9 c1e cfe cff cff c66 c2e c0f c1f c84 c00 c00 c00 c00 c00 c0f c1f c40 c00 c55 c48 c89 ce5 c<48> c8b c75 c08 c65 c48 c8b c04 c25 c00 c7e c01 c00 c65 c8b c15 c88 cab ccf c7e c81 c