INFO: task syz-executor.5:16847 blocked for more than 143 seconds. Not tainted 5.8.0-rc5-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D28760 16847 7372 0x00004004 Call Trace: context_switch kernel/sched/core.c:3453 [inline] __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4178 schedule+0xd0/0x2a0 kernel/sched/core.c:4253 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1873 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: 0033:0x45c1d9 Code: Bad RIP value. RSP: 002b:00007f08a9797c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000010b00 RCX: 000000000045c1d9 RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000005 RBP: 000000000078bf38 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c R13: 00007fff709be1cf R14: 00007f08a97989c0 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 3 locks held by in:imklog/6462: #0: ffff88809deeb430 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826 #1: ffffffff89bb5c38 (logbuf_lock){-.-.}-{2:2}, at: is_bpf_text_address+0x0/0x160 kernel/bpf/core.c:691 #2: ffff8880ae720f08 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x2fb/0x400 kernel/sched/psi.c:817 2 locks held by kworker/u5:2/14245: #0: ffff888091c0c138 ((wq_completion)knbd5-recv){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888091c0c138 ((wq_completion)knbd5-recv){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline] #0: ffff888091c0c138 ((wq_completion)knbd5-recv){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline] #0: ffff888091c0c138 ((wq_completion)knbd5-recv){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline] #0: ffff888091c0c138 ((wq_completion)knbd5-recv){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888091c0c138 ((wq_completion)knbd5-recv){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240 #1: ffffc900040e7da8 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1153 Comm: khungtaskd Not tainted 5.8.0-rc5-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: 3881 Comm: systemd-journal Not tainted 5.8.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:stack_trace_save+0x14/0xc0 kernel/stacktrace.c:115 Code: e8 81 5d 50 00 48 8b 34 24 e9 59 ff ff ff 0f 1f 84 00 00 00 00 00 48 b8 00 00 00 00 00 fc ff df 53 83 c2 01 31 c9 48 83 c4 80 <48> 89 e3 48 c7 04 24 b3 8a b5 41 48 c7 44 24 08 24 5a 68 89 48 c1 RSP: 0018:ffffc90001657b58 EFLAGS: 00000083 RAX: dffffc0000000000 RBX: 0000000000000001 RCX: 0000000000000000 RDX: 0000000000000001 RSI: 0000000000000040 RDI: ffffc90001657be8 RBP: ffff88809920bfb8 R08: 0000000000000001 R09: ffffed10132417e0 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000800 R13: ffff8880aa1d0a80 R14: dffffc0000000000 R15: 0000000000000000 FS: 00007f235f4a08c0(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f235c8f9000 CR3: 00000000a916c000 CR4: 00000000001406e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: save_stack+0x1b/0x40 mm/kasan/common.c:48 set_track mm/kasan/common.c:56 [inline] kasan_set_free_info mm/kasan/common.c:316 [inline] __kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455 __cache_free mm/slab.c:3426 [inline] kmem_cache_free+0x7f/0x310 mm/slab.c:3694 __put_cred+0x1de/0x250 kernel/cred.c:148 put_cred include/linux/cred.h:287 [inline] put_cred include/linux/cred.h:280 [inline] revert_creds+0x1a8/0x1f0 kernel/cred.c:598 do_faccessat+0x2ca/0x820 fs/open.c:464 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f235e75c9c7 Code: Bad RIP value. RSP: 002b:00007ffc7efa03b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000015 RAX: ffffffffffffffda RBX: 00007ffc7efa33e0 RCX: 00007f235e75c9c7 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 000055ff4666a9a3 RBP: 00007ffc7efa0500 R08: 000055ff466603e5 R09: 0000000000000018 R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 000055ff4819e8c0 R15: 00007ffc7efa09f0