INFO: task syz-executor.3:2113 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.3 D25016 2113 1 0x00000004 ffff8801d0640000 ffff8801d3d6f380 ffff8801db621000 ffff8801d3a92f80 ffff8801db621018 ffff8801aea77a28 ffffffff82801a4e ffffffff82e2bb68 ffffffff81208040 0000000000000000 ffff8801db6218f0 1ffff10035d4ef34 Call Trace: [<0000000099361d18>] schedule+0x92/0x1c0 kernel/sched/core.c:3546 [<00000000334f1d2a>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579 [<00000000b49ff402>] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [<00000000b49ff402>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621 [<00000000936e8bab>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405 [<000000004df4420e>] __blkdev_driver_ioctl block/ioctl.c:294 [inline] [<000000004df4420e>] blkdev_ioctl+0xe14/0x19e0 block/ioctl.c:590 [<0000000080363616>] block_ioctl+0xde/0x120 fs/block_dev.c:1696 [<0000000018cbc354>] vfs_ioctl fs/ioctl.c:43 [inline] [<0000000018cbc354>] file_ioctl fs/ioctl.c:493 [inline] [<0000000018cbc354>] do_vfs_ioctl+0xb87/0x11d0 fs/ioctl.c:677 [<000000009f1b6f51>] SYSC_ioctl fs/ioctl.c:694 [inline] [<000000009f1b6f51>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685 [<000000000c9b6df2>] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 [<000000004c9bdc1f>] 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: [<000000008cc3097f>] check_hung_uninterruptible_tasks kernel/hung_task.c:169 [inline] #0: (rcu_read_lock){......}, at: [<000000008cc3097f>] watchdog+0x14b/0xaf0 kernel/hung_task.c:263 #1: (tasklist_lock){.+.+..}, at: [<00000000a0bf685c>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4339 1 lock held by rsyslogd/1896: #0: (&f->f_pos_lock){+.+.+.}, at: [<00000000e41f13c2>] __fdget_pos+0xa8/0xd0 fs/file.c:782 2 locks held by getty/2023: #0: (&tty->ldisc_sem){++++++}, at: [<00000000506b1d6b>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+...}, at: [<00000000615e11d6>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.3/2113: #0: (loop_ctl_mutex/1){+.+.+.}, at: [<00000000936e8bab>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405 2 locks held by syz-executor.1/2114: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000495ffdfd>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000545b74e7>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 2 locks held by syz-executor.2/2139: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000495ffdfd>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000545b74e7>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 3 locks held by syz-executor.5/2140: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000bb590831>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1587 #1: (loop_index_mutex){+.+.+.}, at: [<000000000e1cce06>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1664 #2: (loop_ctl_mutex#2){+.+.+.}, at: [<000000007c70e769>] __lo_release drivers/block/loop.c:1642 [inline] #2: (loop_ctl_mutex#2){+.+.+.}, at: [<000000007c70e769>] lo_release+0x84/0x1b0 drivers/block/loop.c:1665 1 lock held by syz-executor.4/22534: #0: (loop_ctl_mutex/1){+.+.+.}, at: [<00000000936e8bab>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405 2 locks held by syz-executor.0/22543: #0: (loop_ctl_mutex/1){+.+.+.}, at: [<00000000936e8bab>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405 #1: (&bdev->bd_mutex){+.+.+.}, at: [<00000000b7154f3e>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189 2 locks held by blkid/22544: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000495ffdfd>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000545b74e7>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 2 locks held by blkid/22546: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000495ffdfd>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<00000000545b74e7>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 1 lock held by blkid/22547: #0: (&bdev->bd_mutex){+.+.+.}, at: [<00000000495ffdfd>] __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: [<000000001d2217c8>] __dump_stack lib/dump_stack.c:15 [inline] [<000000001d2217c8>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<0000000074d1e695>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99 [<00000000c35096b2>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60 [<000000002eac9cfc>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [<00000000fc031af6>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [<00000000fc031af6>] check_hung_task kernel/hung_task.c:126 [inline] [<00000000fc031af6>] check_hung_uninterruptible_tasks kernel/hung_task.c:183 [inline] [<00000000fc031af6>] watchdog+0x670/0xaf0 kernel/hung_task.c:263 [<00000000905dbad7>] kthread+0x278/0x310 kernel/kthread.c:211 [<00000000adab8cd8>] 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: 0 Comm: swapper/0 Not tainted 4.9.170+ #48 task: 00000000e09a537e task.stack: 000000002d178b66 RIP: 0010:[] c [<00000000b39fb9e0>] check_preemption_disabled+0x1c/0x200 lib/smp_processor_id.c:13 RSP: 0018:ffff8801db607640 EFLAGS: 00000206 RAX: ffffffff83031180 RBX: ffff8801db6077a0 RCX: 1ffffffff063f7a4 RDX: 0000000000000100 RSI: ffffffff81bb618c RDI: ffffffff82b432e0 RBP: ffff8801db607670 R08: 0000000000000000 R09: ffffffff83031a78 R10: ffffffff83031a58 R11: 0000000000000001 R12: ffff8801d5dd1a80 R13: ffffffff82b432a0 R14: ffffffff82b432e0 R15: ffff8801d6750000 FS: 0000000000000000(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000002639000 CR3: 00000001ce550000 CR4: 00000000001606b0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Stack: ffffed003aa0fa53c ffff8801db6077a0c ffff8801d5dd1a80c ffff8801c4f35500c ffffffff83368380c ffff8801d6750000c ffff8801db607680c ffffffff81bb638cc ffff8801db6076a0c ffffffff812481a5c 5181cfa22f556be8c ffff8801db6077a0c Call Trace: d [<0000000098bd6afa>] debug_smp_processor_id+0x1c/0x20 lib/smp_processor_id.c:56 [<00000000a342cb0a>] __rcu_is_watching kernel/rcu/tree.c:1053 [inline] [<00000000a342cb0a>] rcu_is_watching+0x15/0xb0 kernel/rcu/tree.c:1067 [<000000004660859a>] rcu_read_lock_held+0x81/0xc0 kernel/rcu/update.c:293 [<000000001568853e>] nf_hook_slow+0x17a/0x1f0 net/netfilter/core.c:353 [<00000000e57d1ea1>] nf_hook_thresh include/linux/netfilter.h:191 [inline] [<00000000e57d1ea1>] NF_HOOK_THRESH include/linux/netfilter.h:230 [inline] [<00000000e57d1ea1>] NF_HOOK include/linux/netfilter.h:255 [inline] [<00000000e57d1ea1>] ip_local_deliver+0x3e9/0x4d0 net/ipv4/ip_input.c:257 [<00000000d979a01d>] dst_input include/net/dst.h:513 [inline] [<00000000d979a01d>] ip_rcv_finish+0x5c4/0x14e0 net/ipv4/ip_input.c:395 [<00000000b003974d>] NF_HOOK_THRESH include/linux/netfilter.h:232 [inline] [<00000000b003974d>] NF_HOOK include/linux/netfilter.h:255 [inline] [<00000000b003974d>] ip_rcv+0xa29/0x1040 net/ipv4/ip_input.c:487 [<000000006df1810e>] __netif_receive_skb_core+0x1156/0x2990 net/core/dev.c:4289 [<00000000a6df3389>] __netif_receive_skb+0x58/0x1c0 net/core/dev.c:4327 [<00000000c7b91299>] netif_receive_skb_internal+0xf8/0x380 net/core/dev.c:4355 [<00000000b2f33c83>] napi_skb_finish net/core/dev.c:4713 [inline] [<00000000b2f33c83>] napi_gro_receive+0x200/0x410 net/core/dev.c:4743 [<00000000f7a5a970>] receive_buf drivers/net/virtio_net.c:508 [inline] [<00000000f7a5a970>] virtnet_receive+0x704/0x1cd0 drivers/net/virtio_net.c:728 [<00000000f563ddcf>] virtnet_poll+0x25/0x140 drivers/net/virtio_net.c:746 [<000000007b93f814>] napi_poll net/core/dev.c:5253 [inline] [<000000007b93f814>] net_rx_action+0x3aa/0xdd0 net/core/dev.c:5318 [<0000000049f39ce9>] __do_softirq+0x22d/0x964 kernel/softirq.c:288 [<00000000516d077d>] invoke_softirq kernel/softirq.c:368 [inline] [<00000000516d077d>] irq_exit+0x119/0x160 kernel/softirq.c:409 [<00000000439c6579>] exiting_irq arch/x86/include/asm/apic.h:669 [inline] [<00000000439c6579>] do_IRQ+0x111/0x1d0 arch/x86/kernel/irq.c:252 [<00000000cb930dc9>] common_interrupt+0x9d/0x9d arch/x86/entry/entry_64.S:461 d [<000000007ecd2a9c>] ? native_safe_halt+0x2/0x10 arch/x86/include/asm/irqflags.h:56 [<000000007b490760>] arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:428 [<00000000d23d067d>] default_idle_call+0x36/0x60 kernel/sched/idle.c:97 [<000000007892199e>] cpuidle_idle_call kernel/sched/idle.c:155 [inline] [<000000007892199e>] cpu_idle_loop kernel/sched/idle.c:248 [inline] [<000000007892199e>] cpu_startup_entry+0x283/0x3a0 kernel/sched/idle.c:303 [<00000000c288f969>] rest_init+0x18b/0x194 init/main.c:409 [<000000009bfbfd11>] start_kernel+0x61e/0x652 init/main.c:671 [<0000000018c67039>] x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:196 [<000000007f303873>] x86_64_start_kernel+0x137/0x15a arch/x86/kernel/head64.c:177 Code: c9b c2c c94 cff ce9 c17 cf7 cff cff c66 c0f c1f c44 c00 c00 c55 c48 c89 ce5 c41 c57 c41 c56 c49 c89 cfe c41 c55 c49 c89 cf5 c41 c54 c53 c48 c83 cec c08 ce8 c24 c70 c76 cff c<65> c44 c8b c25 c9c cff c45 c7e c65 c8b c05 cf5 c1b c46 c7e ca9 cff cff cff c7f c74 c