INFO: task syz-executor.0:5500 blocked for more than 143 seconds.
      Not tainted 6.9.0-syzkaller-12277-g56fb6f92854f #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0  state:D stack:26928 pid:5500  tgid:5499  ppid:5436   flags:0x00004006
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5408 [inline]
 __schedule+0xf15/0x5d00 kernel/sched/core.c:6745
 __schedule_loop kernel/sched/core.c:6822 [inline]
 schedule+0xe7/0x350 kernel/sched/core.c:6837
 schedule_timeout+0x258/0x2a0 kernel/time/timer.c:2557
 do_wait_for_common kernel/sched/completion.c:95 [inline]
 __wait_for_common+0x3de/0x5f0 kernel/sched/completion.c:116
 __flush_workqueue+0x39e/0x1200 kernel/workqueue.c:3972
 nbd_start_device_ioctl drivers/block/nbd.c:1466 [inline]
 __nbd_ioctl drivers/block/nbd.c:1527 [inline]
 nbd_ioctl+0x308/0xfd0 drivers/block/nbd.c:1567
 blkdev_ioctl+0x27c/0x6e0 block/ioctl.c:676
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0x193/0x220 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9dd027cda9
RSP: 002b:00007f9dd0f9f0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f9dd03abf80 RCX: 00007f9dd027cda9
RDX: 0000000000000000 RSI: 000000000000ab03 RDI: 0000000000000003
RBP: 00007f9dd02c947a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f9dd03abf80 R15: 00007ffc69ffa378
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/30:
 #0: ffffffff8dbb17e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #0: ffffffff8dbb17e0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #0: ffffffff8dbb17e0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x75/0x340 kernel/locking/lockdep.c:6614
2 locks held by kworker/u9:1/4477:
 #0: ffff888020a61148 ((wq_completion)nbd0-recv){+.+.}-{0:0}, at: process_one_work+0x12bf/0x1b60 kernel/workqueue.c:3206
 #1: ffffc9000ccd7d80 ((work_completion)(&args->work)){+.+.}-{0:0}, at: process_one_work+0x957/0x1b60 kernel/workqueue.c:3207
2 locks held by getty/4829:
 #0: ffff88802ea290a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
 #1: ffffc90002f062f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xfc8/0x1490 drivers/tty/n_tty.c:2201
1 lock held by syz-executor.0/9421:
 #0: ffff8880209d5998 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x151/0xfd0 drivers/block/nbd.c:1560
1 lock held by syz-executor.0/9422:
 #0: ffff8880209d5998 (&nbd->config_lock){+.+.}-{3:3}, at: nbd_ioctl+0x151/0xfd0 drivers/block/nbd.c:1560

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

NMI backtrace for cpu 1
CPU: 1 PID: 30 Comm: khungtaskd Not tainted 6.9.0-syzkaller-12277-g56fb6f92854f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
 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:162 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:223 [inline]
 watchdog+0xf86/0x1240 kernel/hung_task.c:379
 kthread+0x2c1/0x3a0 kernel/kthread.c:389
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4515 Comm: syslogd Not tainted 6.9.0-syzkaller-12277-g56fb6f92854f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
RIP: 0010:stack_access_ok+0x1d/0x270 arch/x86/kernel/unwind_orc.c:390
Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 41 57 41 56 41 55 41 54 55 48 89 f5 53 48 89 fb 4c 8d 63 08 48 83 ec 10 48 89 54 24 08 <e8> 9e 0f 51 00 4c 89 e2 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03
RSP: 0018:ffffc9000cc374f8 EFLAGS: 00000282
RAX: 0000000000000000 RBX: ffffc9000cc375c0 RCX: 0000000000000001
RDX: 0000000000000008 RSI: ffffc9000cc37ef8 RDI: ffffc9000cc375c0
RBP: ffffc9000cc37ef8 R08: 0000000000000001 R09: 0000000000000004
R10: 0000000000000001 R11: 0000000000000001 R12: ffffc9000cc375c8
R13: ffffc9000cc37f28 R14: 0000000000000001 R15: 0000000000000001
FS:  00007fcfe0856380(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd2437a80c0 CR3: 0000000054f6c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline]
 unwind_next_frame+0x1b94/0x23a0 arch/x86/kernel/unwind_orc.c:648
 arch_stack_walk+0x100/0x170 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x95/0xd0 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+0x3b/0x60 mm/kasan/generic.c:579
 poison_slab_object+0xf7/0x160 mm/kasan/common.c:240
 __kasan_slab_free+0x32/0x50 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2195 [inline]
 slab_free mm/slub.c:4436 [inline]
 kmem_cache_free+0x12f/0x3a0 mm/slub.c:4511
 kfree_skbmem+0x10e/0x200 net/core/skbuff.c:1131
 __kfree_skb net/core/skbuff.c:1188 [inline]
 consume_skb net/core/skbuff.c:1409 [inline]
 consume_skb+0xdd/0x170 net/core/skbuff.c:1403
 __unix_dgram_recvmsg+0x821/0xe50 net/unix/af_unix.c:2469
 unix_dgram_recvmsg+0xd0/0x110 net/unix/af_unix.c:2486
 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
 new_sync_read fs/read_write.c:395 [inline]
 vfs_read+0xa39/0xbd0 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+0xcd/0x250 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcfe09aab6a
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:00007fff17e721d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fcfe09aab6a
RDX: 00000000000000ff RSI: 0000563e6514c300 RDI: 0000000000000000
RBP: 0000563e6514c2c0 R08: 0000000000000001 R09: 0000000000000000
R10: 00007fcfe0b493a3 R11: 0000000000000246 R12: 0000563e6514c348
R13: 0000563e6514c300 R14: 0000000000000000 R15: 00007fcfe0b8da80
 </TASK>