INFO: task syz-executor.0:5503 blocked for more than 143 seconds.
      Not tainted 6.8.0-rc5-syzkaller-00329-gab0a97cffa0b #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:27888 pid:5503  tgid:5496  ppid:5429   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5400 [inline]
 __schedule+0xf12/0x5c60 kernel/sched/core.c:6727
 __schedule_loop kernel/sched/core.c:6802 [inline]
 schedule+0xe9/0x280 kernel/sched/core.c:6817
 schedule_timeout+0x25b/0x2a0 kernel/time/timer.c:2159
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common+0x3e4/0x600 kernel/sched/completion.c:116
 __flush_workqueue+0x3e0/0x1340 kernel/workqueue.c:3198
 nbd_start_device_ioctl drivers/block/nbd.c:1443 [inline]
 __nbd_ioctl drivers/block/nbd.c:1504 [inline]
 nbd_ioctl+0x308/0xd60 drivers/block/nbd.c:1544
 blkdev_ioctl+0x2f7/0x770 block/ioctl.c:634
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl fs/ioctl.c:857 [inline]
 __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xd5/0x270 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x6f/0x77
RIP: 0033:0x7fd3c987cae9
RSP: 002b:00007fd3ca5dd0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fd3c999c050 RCX: 00007fd3c987cae9
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003
RBP: 00007fd3c98c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000006e R14: 00007fd3c999c050 R15: 00007ffc8cd45568
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/29:
 #0: ffffffff8d7ad2e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:298 [inline]
 #0: ffffffff8d7ad2e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:750 [inline]
 #0: ffffffff8d7ad2e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x75/0x340 kernel/locking/lockdep.c:6614
2 locks held by getty/4821:
 #0: ffff88802a3550a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc900015c02f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfca/0x1490 drivers/tty/n_tty.c:2201
2 locks held by kworker/u5:2/5074:
 #0: ffff88801fc0e938 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x789/0x15e0 kernel/workqueue.c:2608
 #1: ffffc900034efd80 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x7eb/0x15e0 kernel/workqueue.c:2609
1 lock held by syz-executor.0/8812:
 #0: ffff888020453998 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x151/0xd60 drivers/block/nbd.c:1537
1 lock held by syz-executor.0/8813:
 #0: ffff888020453998 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x151/0xd60 drivers/block/nbd.c:1537

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 29 Comm: khungtaskd Not tainted 6.8.0-rc5-syzkaller-00329-gab0a97cffa0b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline]
 watchdog+0xf87/0x1210 kernel/hung_task.c:379
 kthread+0x2c6/0x3b0 kernel/kthread.c:388
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242
 </TASK>
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4497 Comm: syslogd Not tainted 6.8.0-rc5-syzkaller-00329-gab0a97cffa0b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:__sanitizer_cov_trace_pc+0x59/0x60 kernel/kcov.c:225
Code: 82 d8 15 00 00 83 f8 02 75 20 48 8b 8a e0 15 00 00 8b 92 dc 15 00 00 48 8b 01 48 83 c0 01 48 39 d0 73 07 48 89 01 48 89 34 c1 <c3> cc cc cc cc 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000342f4f0 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffffffff900f5b04 RCX: ffffffff813c4a84
RDX: ffff88807e093b80 RSI: ffffffff813c4a3a RDI: 0000000000000006
RBP: ffffffff900f5b04 R08: 0000000000000006 R09: ffffffff8968c373
R10: ffffffff8968c3d7 R11: 0000000000000001 R12: ffffffff8968c373
R13: ffffffff8968c3d7 R14: dffffc0000000000 R15: ffffffff900f5b08
FS:  00007f0e0e706380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcdb57980c0 CR3: 000000002f354000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 __orc_find+0x7a/0x130 arch/x86/kernel/unwind_orc.c:100
 orc_find arch/x86/kernel/unwind_orc.c:227 [inline]
 unwind_next_frame+0x32d/0x2390 arch/x86/kernel/unwind_orc.c:494
 arch_stack_walk+0x100/0x170 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x96/0xd0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3f/0x60 mm/kasan/generic.c:643
 poison_slab_object mm/kasan/common.c:241 [inline]
 __kasan_slab_free+0x121/0x1c0 mm/kasan/common.c:257
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2121 [inline]
 slab_free mm/slub.c:4299 [inline]
 kmem_cache_free+0x129/0x360 mm/slub.c:4363
 kfree_skbmem+0xef/0x1b0 net/core/skbuff.c:1051
 __kfree_skb net/core/skbuff.c:1109 [inline]
 consume_skb net/core/skbuff.c:1324 [inline]
 consume_skb+0xdf/0x170 net/core/skbuff.c:1318
 __unix_dgram_recvmsg+0x814/0xef0 net/unix/af_unix.c:2453
 unix_dgram_recvmsg+0xd0/0x110 net/unix/af_unix.c:2470
 sock_recvmsg_nosec net/socket.c:1046 [inline]
 sock_recvmsg+0x1f6/0x250 net/socket.c:1068
 sock_read_iter+0x2c7/0x3c0 net/socket.c:1138
 call_read_iter include/linux/fs.h:2081 [inline]
 new_sync_read fs/read_write.c:395 [inline]
 vfs_read+0xa01/0xb80 fs/read_write.c:476
 ksys_read+0x1f8/0x260 fs/read_write.c:619
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xd5/0x270 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x6f/0x77
RIP: 0033:0x7f0e0e85ab6a
Code: 00 3d 00 00 41 00 75 0d 50 48 8d 3d 2d 08 0a 00 e8 ea 7d 01 00 31 c0 e9 07 ff ff ff 64 8b 04 25 18 00 00 00 85 c0 75 1b 0f 05 <48> 3d 00 f0 ff ff 76 6c 48 8b 15 8f a2 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007fff3c215f48 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f0e0e85ab6a
RDX: 00000000000000ff RSI: 00005582f68ca300 RDI: 0000000000000000
RBP: 00005582f68ca2c0 R08: 0000000000000001 R09: 0000000000000000
R10: 00007f0e0e9f93a3 R11: 0000000000000246 R12: 00005582f68ca351
R13: 00005582f68ca300 R14: 0000000000000000 R15: 00007f0e0ea37a80
 </TASK>