INFO: task syz-executor.2:21488 blocked for more than 143 seconds. Not tainted 5.6.0-rc7-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D28328 21488 7375 0x00004004 Call Trace: schedule+0xd0/0x2a0 kernel/sched/core.c:4154 schedule_timeout+0x6db/0xba0 kernel/time/timer.c:1871 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x26a/0x3c0 kernel/sched/completion.c:136 flush_workqueue+0x40a/0x14c0 kernel/workqueue.c:2829 nbd_start_device_ioctl drivers/block/nbd.c:1311 [inline] __nbd_ioctl drivers/block/nbd.c:1386 [inline] nbd_ioctl+0x7ae/0xb7c drivers/block/nbd.c:1426 __blkdev_driver_ioctl block/ioctl.c:321 [inline] blkdev_ioctl+0x25b/0x660 block/ioctl.c:717 block_ioctl+0xe9/0x130 fs/block_dev.c:1983 vfs_ioctl fs/ioctl.c:47 [inline] ksys_ioctl+0x11a/0x180 fs/ioctl.c:763 __do_sys_ioctl fs/ioctl.c:772 [inline] __se_sys_ioctl fs/ioctl.c:770 [inline] __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:770 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45c849 Code: Bad RIP value. RSP: 002b:00007fe4d157ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fe4d157f6d4 RCX: 000000000045c849 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003 RBP: 000000000076bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 0000000000000401 R14: 00000000004c69df R15: 000000000076bf0c Showing all locks held in the system: 1 lock held by khungtaskd/1075: #0: ffffffff897accc0 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5331 2 locks held by kworker/u5:0/1619: #0: ffff888099c64928 ((wq_completion)knbd2-recv){+.+.}, at: __write_once_size include/linux/compiler.h:226 [inline] #0: ffff888099c64928 ((wq_completion)knbd2-recv){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888099c64928 ((wq_completion)knbd2-recv){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: ffff888099c64928 ((wq_completion)knbd2-recv){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: ffff888099c64928 ((wq_completion)knbd2-recv){+.+.}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff888099c64928 ((wq_completion)knbd2-recv){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:642 [inline] #0: ffff888099c64928 ((wq_completion)knbd2-recv){+.+.}, at: process_one_work+0x82a/0x1690 kernel/workqueue.c:2237 #1: ffffc90005807dd0 ((work_completion)(&args->work)){+.+.}, at: process_one_work+0x85e/0x1690 kernel/workqueue.c:2241 1 lock held by in:imklog/6755: #0: ffff88809c3a4ae0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:826 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1075 Comm: khungtaskd Not tainted 5.6.0-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+0x188/0x20d lib/dump_stack.c:118 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xa8c/0x1010 kernel/hung_task.c:289 kthread+0x357/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 4244 Comm: systemd-journal Not tainted 5.6.0-rc7-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:orc_ip arch/x86/kernel/unwind_orc.c:27 [inline] RIP: 0010:__orc_find+0x83/0xf0 arch/x86/kernel/unwind_orc.c:49 Code: 01 c2 48 d1 fa 48 8d 5c 95 00 48 89 d8 48 c1 e8 03 42 0f b6 14 38 48 89 d8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 48 48 63 13 <48> 01 da 48 39 d1 73 b0 4c 8d 63 fc 49 39 ec 73 b3 4d 29 ee 49 c1 RSP: 0018:ffffc90001667728 EFLAGS: 00000046 RAX: 0000000000000007 RBX: ffffffff8a7a5d24 RCX: ffffffff81bd687d RDX: fffffffff7430adf RSI: ffffffff8ad73da0 RDI: ffffffff8a7a5d20 RBP: ffffffff8a7a5d20 R08: 000000000002afca R09: ffffffff8ad73db2 R10: 000000000002afc8 R11: 000000000006e027 R12: ffffffff8a7a5d28 R13: ffffffff8a7a5d20 R14: ffffffff8a7a5d20 R15: dffffc0000000000 FS: 00007f983c7a08c0(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9839c2c000 CR3: 00000000929c7000 CR4: 00000000001426f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: orc_find arch/x86/kernel/unwind_orc.c:173 [inline] unwind_next_frame+0x34b/0x19d0 arch/x86/kernel/unwind_orc.c:407 arch_stack_walk+0x74/0xd0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8c/0xc0 kernel/stacktrace.c:123 save_stack+0x1b/0x80 mm/kasan/common.c:72 set_track mm/kasan/common.c:80 [inline] kasan_set_free_info mm/kasan/common.c:337 [inline] __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:476 __cache_free mm/slab.c:3426 [inline] kmem_cache_free+0x7f/0x320 mm/slab.c:3694 putname+0xe1/0x120 fs/namei.c:259 filename_parentat.isra.0+0x38c/0x400 fs/namei.c:2516 filename_create+0x9e/0x4a0 fs/namei.c:3691 user_path_create fs/namei.c:3766 [inline] do_mkdirat+0xa0/0x280 fs/namei.c:3904 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f983ba5c687 Code: 00 b8 ff ff ff ff c3 0f 1f 40 00 48 8b 05 09 d8 2b 00 64 c7 00 5f 00 00 00 b8 ff ff ff ff c3 0f 1f 40 00 b8 53 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d e1 d7 2b 00 f7 d8 64 89 01 48 RSP: 002b:00007ffec31ea7c8 EFLAGS: 00000293 ORIG_RAX: 0000000000000053 RAX: ffffffffffffffda RBX: 00007ffec31ed6e0 RCX: 00007f983ba5c687 RDX: 00007f983c4cda00 RSI: 00000000000001ed RDI: 0000559e080f78a0 RBP: 00007ffec31ea800 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000069 R11: 0000000000000293 R12: 0000000000000000 R13: 0000000000000000 R14: 00007ffec31ed6e0 R15: 00007ffec31eacf0