INFO: task syz-executor.0:20187 blocked for more than 143 seconds. Not tainted 5.8.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D28720 20187 6962 0x00004004 Call Trace: context_switch kernel/sched/core.c:3458 [inline] __schedule+0x8ea/0x2210 kernel/sched/core.c:4219 schedule+0xd0/0x2a0 kernel/sched/core.c:4294 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1892 do_wait_for_common kernel/sched/completion.c:85 [inline] __wait_for_common kernel/sched/completion.c:106 [inline] wait_for_common kernel/sched/completion.c:117 [inline] wait_for_completion+0x163/0x260 kernel/sched/completion.c:138 flush_workqueue+0x3ff/0x13e0 kernel/workqueue.c:2832 nbd_start_device_ioctl drivers/block/nbd.c:1327 [inline] __nbd_ioctl drivers/block/nbd.c:1402 [inline] nbd_ioctl+0x7ac/0xb77 drivers/block/nbd.c:1442 __blkdev_driver_ioctl block/ioctl.c:224 [inline] blkdev_ioctl+0x255/0x6c0 block/ioctl.c:620 block_ioctl+0xf9/0x140 fs/block_dev.c:1988 vfs_ioctl fs/ioctl.c:48 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:753 __do_sys_ioctl fs/ioctl.c:762 [inline] __se_sys_ioctl fs/ioctl.c:760 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:760 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45cc79 Code: Bad RIP value. RSP: 002b:00007f5b2e6a6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000011bc0 RCX: 000000000045cc79 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 000000000078bf38 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c R13: 00007fffa0ea98af R14: 00007f5b2e6a79c0 R15: 000000000078bf0c Showing all locks held in the system: 2 locks held by kworker/u4:0/7: #0: ffff8880ae635e18 (&rq->lock){-.-.}-{2:2}, at: rq_lock kernel/sched/sched.h:1261 [inline] #0: ffff8880ae635e18 (&rq->lock){-.-.}-{2:2}, at: __schedule+0x22f/0x2210 kernel/sched/core.c:4137 #1: ffffffff89bc11c0 (rcu_read_lock){....}-{1:2}, at: cpu_of kernel/sched/sched.h:1051 [inline] #1: ffffffff89bc11c0 (rcu_read_lock){....}-{1:2}, at: __update_idle_core+0x39/0x3e0 kernel/sched/fair.c:6006 1 lock held by khungtaskd/1154: #0: ffffffff89bc11c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779 2 locks held by kworker/u5:0/1534: #0: ffff888092d2d138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888092d2d138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888092d2d138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888092d2d138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888092d2d138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888092d2d138 ((wq_completion)knbd0-recv){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc900055e7da8 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 1 lock held by in:imklog/6852: #0: ffff88809aff3870 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1154 Comm: khungtaskd Not tainted 5.8.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x18f/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0xd7d/0x1000 kernel/hung_task.c:295 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 7 Comm: kworker/u4:0 Not tainted 5.8.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: bat_events batadv_iv_send_outstanding_bat_ogm_packet RIP: 0010:__sanitizer_cov_trace_const_cmp1+0x0/0x20 kernel/kcov.c:270 Code: 66 2e 0f 1f 84 00 00 00 00 00 48 8b 0c 24 48 89 f2 48 89 fe bf 06 00 00 00 e9 0c ff ff ff 66 90 66 2e 0f 1f 84 00 00 00 00 00 <48> 8b 0c 24 40 0f b6 d6 40 0f b6 f7 bf 01 00 00 00 e9 ea fe ff ff RSP: 0018:ffffc90000cdfb90 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff87c8cdf3 RDX: ffff8880a95e41c0 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: ffffffff8c5a5a27 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88809ea96094 R13: dffffc0000000000 R14: ffff888093564bc0 R15: 00000000000000e3 FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6a40200000 CR3: 00000000a75a7000 CR4: 00000000001406f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: rcu_read_unlock include/linux/rcupdate.h:684 [inline] batadv_iv_ogm_slide_own_bcast_window net/batman-adv/bat_iv_ogm.c:771 [inline] batadv_iv_ogm_schedule_buff+0x77c/0x1410 net/batman-adv/bat_iv_ogm.c:825 batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:869 [inline] batadv_iv_ogm_schedule net/batman-adv/bat_iv_ogm.c:862 [inline] batadv_iv_send_outstanding_bat_ogm_packet+0x5c8/0x800 net/batman-adv/bat_iv_ogm.c:1722 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415 kthread+0x3b5/0x4a0 kernel/kthread.c:291 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293