INFO: task syz-executor.5:2101 blocked for more than 140 seconds. Not tainted 4.9.194+ #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D25016 2101 1 0x00000004 0000000000000087 ffff8801d26a97c0 ffff8801cee95d80 ffff8801db721000 ffff8801d1834740 ffff8801db721018 ffff8801a80276a8 ffffffff8281af8e 0000000000000246 ffffffff831f3ca8 00ff8801d26aa068 ffff8801db7218f0 Call Trace: [<000000007f63203d>] schedule+0x92/0x1c0 kernel/sched/core.c:3546 [<00000000b948b8fa>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579 [<0000000059f65ca0>] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [<0000000059f65ca0>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621 [<00000000d7b00fb4>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 [<00000000710446a2>] blkdev_get+0x2e8/0x920 fs/block_dev.c:1424 [<00000000c1bb7eaf>] blkdev_open+0x1aa/0x250 fs/block_dev.c:1579 [<00000000619efd3c>] do_dentry_open+0x422/0xd20 fs/open.c:791 [<00000000e5ea19d9>] vfs_open+0x105/0x230 fs/open.c:904 [<000000008b4e271a>] do_last fs/namei.c:3541 [inline] [<000000008b4e271a>] path_openat+0xbf5/0x2f60 fs/namei.c:3665 [<0000000061d9b503>] do_filp_open+0x1a1/0x280 fs/namei.c:3699 [<000000007c7e82a2>] do_sys_open+0x2f0/0x610 fs/open.c:1097 [<000000001ce5b0d5>] SYSC_open fs/open.c:1115 [inline] [<000000001ce5b0d5>] SyS_open+0x2d/0x40 fs/open.c:1110 [<0000000014f0d5b5>] do_syscall_64+0x1ad/0x5c0 arch/x86/entry/common.c:288 [<000000007a2a6d00>] 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: [<00000000375c055e>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline] #0: (rcu_read_lock){......}, at: [<00000000375c055e>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263 #1: (tasklist_lock){.+.+..}, at: [<0000000004cffba6>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4336 2 locks held by getty/2019: #0: (&tty->ldisc_sem){++++++}, at: [<0000000032dd8aea>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&ldata->atomic_read_lock){+.+...}, at: [<00000000e5cbba1d>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.5/2101: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000d7b00fb4>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 2 locks held by syz-executor.3/2106: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000d7b00fb4>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<0000000005b8c484>] lo_open+0x1d/0xb0 drivers/block/loop.c:1621 2 locks held by syz-executor.1/2111: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000d7b00fb4>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<0000000005b8c484>] lo_open+0x1d/0xb0 drivers/block/loop.c:1621 2 locks held by syz-executor.4/13309: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000d7b00fb4>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<0000000005b8c484>] lo_open+0x1d/0xb0 drivers/block/loop.c:1621 2 locks held by syz-executor.0/13298: #0: (&lo->lo_ctl_mutex/1){+.+.+.}, at: [<00000000420712af>] lo_ioctl+0x8e/0x1b10 drivers/block/loop.c:1404 #1: (&bdev->bd_mutex){+.+.+.}, at: [<00000000616a8739>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189 2 locks held by syz-executor.2/13306: #0: (loop_index_mutex){+.+.+.}, at: [<00000000ba2aee60>] loop_control_ioctl+0x7a/0x320 drivers/block/loop.c:1973 #1: (&lo->lo_ctl_mutex#2){+.+.+.}, at: [<00000000761d90e1>] loop_control_ioctl+0x17f/0x320 drivers/block/loop.c:1987 2 locks held by blkid/13313: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000d7b00fb4>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<0000000005b8c484>] lo_open+0x1d/0xb0 drivers/block/loop.c:1621 1 lock held by blkid/13314: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000d7b00fb4>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 2 locks held by blkid/13316: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000d7b00fb4>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<0000000005b8c484>] lo_open+0x1d/0xb0 drivers/block/loop.c:1621 1 lock held by blkid/13318: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000d7b00fb4>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.194+ #0 ffff8801d98d7cc8 ffffffff81b67001 0000000000000001 0000000000000000 0000000000000001 ffffffff81099d01 dffffc0000000000 ffff8801d98d7d00 ffffffff81b7229c 0000000000000001 0000000000000000 0000000000000001 Call Trace: [<00000000cd0a5136>] __dump_stack lib/dump_stack.c:15 [inline] [<00000000cd0a5136>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<00000000a72bc053>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99 [<000000000bca680c>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60 [<000000008bad6164>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [<00000000e288e010>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [<00000000e288e010>] check_hung_task kernel/hung_task.c:126 [inline] [<00000000e288e010>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline] [<00000000e288e010>] watchdog+0x670/0xaf0 kernel/hung_task.c:263 [<000000005964f813>] kthread+0x278/0x310 kernel/kthread.c:211 [<00000000200b82dd>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:375 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 351 Comm: kworker/0:2 Not tainted 4.9.194+ #0 Workqueue: events_power_efficient gc_workerc task: 00000000c5ba4be5 task.stack: 000000003cc47fd0 RIP: 0010:[] c [<00000000baa88156>] __lock_acquire+0x417/0x4390 kernel/locking/lockdep.c:3300 RSP: 0018:ffff8801d519f960 EFLAGS: 00000002 RAX: 00000000000e0276 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffff8801d5cdb8cc RSI: 0000000000000276 RDI: ffff8801d5cdb8cc RBP: ffff8801d519fae8 R08: 0000000000000001 R09: 0000000000000001 R10: ffff8801d5cdb8a8 R11: 1ffff1003ab9b714 R12: 0000000000000000 R13: 0000000000000276 R14: 0000000000000003 R15: ffff8801d5cdaf80 FS: 0000000000000000(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000013e43e0 CR3: 00000001d806f000 CR4: 00000000001606b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffffff8120d100c 0000000000000000c 0012001800000000c ffffffff842897b8c 0000000000000011c 1ffff1003aa33f33c ffffe8ff00000000c ffff8801d519f9d8c ffffffff81bcd65cc 0000000000000275c 000060fe24610e28c ffffffff830c31e0c Call Trace: [<00000000c63e47d6>] lock_acquire+0x133/0x3d0 kernel/locking/lockdep.c:3756 [<00000000dafde303>] seqcount_lockdep_reader_access include/linux/seqlock.h:80 [inline] [<00000000dafde303>] read_seqcount_begin include/linux/seqlock.h:163 [inline] [<00000000dafde303>] nf_conntrack_get_ht include/net/netfilter/nf_conntrack.h:325 [inline] [<00000000dafde303>] gc_worker+0x11d/0x600 net/netfilter/nf_conntrack_core.c:1022 [<00000000be92ac3f>] process_one_work+0x88b/0x1600 kernel/workqueue.c:2114 [<00000000fc23758a>] worker_thread+0x5df/0x11d0 kernel/workqueue.c:2251 [<000000005964f813>] kthread+0x278/0x310 kernel/kthread.c:211 [<00000000200b82dd>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:375 Code: ce1 c00 c00 c04 c00 c09 cc8 c31 cc9 c45 c85 cc9 c0f c95 cc1 c81 ce2 cff c1f c00 c00 cc1 ce1 c13 c09 cc8 c8b c4d c20 cc1 ce1 c14 c09 cc8 c09 cd0 c48 c89 cfa c41 c89 c42 c20 c<48> cc1 cea c03 c48 cb8 c00 c00 c00 c00 c00 cfc cff cdf c0f cb6 c14 c02 c48 c89 cf8 c