INFO: task syz-executor.4:19011 blocked for more than 143 seconds. Not tainted 5.8.0-rc6-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.4 D28624 19011 7312 0x00004004 Call Trace: context_switch kernel/sched/core.c:3458 [inline] __schedule+0x91f/0x2250 kernel/sched/core.c:4215 schedule+0xd0/0x2a0 kernel/sched/core.c:4290 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1884 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: 0033:0x45c369 Code: Bad RIP value. RSP: 002b:00007ff91815ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000011bc0 RCX: 000000000045c369 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000005 RBP: 000000000078bf38 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c R13: 00007fff0426925f R14: 00007ff91815f9c0 R15: 000000000078bf0c Showing all locks held in the system: 1 lock held by khungtaskd/1153: #0: ffffffff89bc11c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779 2 locks held by kworker/u5:0/1526: #0: ffff88809f808938 ((wq_completion)knbd4-recv){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88809f808938 ((wq_completion)knbd4-recv){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff88809f808938 ((wq_completion)knbd4-recv){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff88809f808938 ((wq_completion)knbd4-recv){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff88809f808938 ((wq_completion)knbd4-recv){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff88809f808938 ((wq_completion)knbd4-recv){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc900052f7da8 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 2 locks held by kworker/u4:5/2764: #0: ffff8880ae735e18 (&rq->lock){-.-.}-{2:2}, at: newidle_balance+0x77f/0xe30 kernel/sched/fair.c:10536 #1: ffff8880ae720f08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x2fb/0x400 kernel/sched/psi.c:817 1 lock held by in:imklog/6496: #0: ffff888097f6bb70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1153 Comm: khungtaskd Not tainted 5.8.0-rc6-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 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3873 Comm: systemd-journal Not tainted 5.8.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x4/0x20 kernel/kcov.c:284 Code: 84 00 00 00 00 00 48 8b 0c 24 0f b7 d6 0f b7 f7 bf 03 00 00 00 e9 cc fe ff ff 66 90 66 2e 0f 1f 84 00 00 00 00 00 48 8b 0c 24 <89> f2 89 fe bf 05 00 00 00 e9 ae fe ff ff 0f 1f 40 00 66 2e 0f 1f RSP: 0018:ffffc900016379e8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff888098c1c79a RCX: ffffffff81cbaee3 RDX: 0000000000000007 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffff88809f320fbf R13: 0000000000000001 R14: dffffc0000000000 R15: ffff88809f320fc0 FS: 00007f67560e28c0(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6753a2a000 CR3: 000000009459d000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: prepend_name+0x173/0x230 fs/d_path.c:49 prepend_path+0x359/0xb20 fs/d_path.c:127 d_absolute_path+0xfa/0x180 fs/d_path.c:201 tomoyo_get_absolute_path security/tomoyo/realpath.c:101 [inline] tomoyo_realpath_from_path+0x282/0x620 security/tomoyo/realpath.c:276 tomoyo_get_realpath security/tomoyo/file.c:151 [inline] tomoyo_path_perm+0x212/0x3f0 security/tomoyo/file.c:822 security_path_truncate+0xcf/0x140 security/security.c:1144 do_sys_ftruncate+0x3f7/0x570 fs/open.c:193 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f67553a5ec7 Code: Bad RIP value. RSP: 002b:00007ffeb8796d08 EFLAGS: 00000202 ORIG_RAX: 000000000000004d RAX: ffffffffffffffda RBX: 00007ffeb8796d40 RCX: 00007f67553a5ec7 RDX: 0000558f67d9ae80 RSI: 0000000000800000 RDI: 0000000000000010 RBP: 00007ffeb8796d38 R08: 0000000000000008 R09: 0000558f67d9b25c R10: 0000558f67d9b1e0 R11: 0000000000000202 R12: 0000558f67d9b1e0 R13: 00007ffeb8796e38 R14: 0000558f67986958 R15: 0005ab4ea4c75099