INFO: task syz.5.3077:20259 blocked for more than 143 seconds.
Tainted: G L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.3077 state:D stack:26648 pid:20259 tgid:20257 ppid:15719
task:syz.5.3077 state:D stack:26648 pid:20259 tgid:20257 ppid:15719 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5526 [inline]
__schedule+0x16d9/0x5700 kernel/sched/core.c:7277
__schedule_loop kernel/sched/core.c:7354 [inline]
rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7661
rt_mutex_slowlock_block+0x55e/0x690 kernel/locking/rtmutex.c:1670
__rt_mutex_slowlock kernel/locking/rtmutex.c:1747 [inline]
__rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1787 [inline]
rt_mutex_slowlock+0x2d4/0x780 kernel/locking/rtmutex.c:1827
__rt_mutex_lock kernel/locking/rtmutex.c:1842 [inline]
__mutex_lock_common kernel/locking/rtmutex_api.c:562 [inline]
mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:580
write_threads+0x3b4/0x610 fs/nfsd/nfsctl.c:436
nfsctl_transaction_write+0x112/0x160 fs/nfsd/nfsctl.c:114
vfs_write+0x29f/0xbb0 fs/read_write.c:685
ksys_write+0x156/0x270 fs/read_write.c:739
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f47a306e159
RSP: 002b:00007f47a12a5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f47a32f6090 RCX: 00007f47a306e159
RDX: 0000000000000002 RSI: 00002000000002c0 RDI: 0000000000000004
RBP: 00007f47a310503b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f47a32f6128 R14: 00007f47a32f6090 R15: 00007ffe2c1e2148
Showing all locks held in the system:
locks held by ktimers/1/29: 9, last CPU#1:
#0: ffffffff8e059500 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3d/0x420 kernel/softirq.c:186
#1: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: psi_task_switch+0x57/0x790 kernel/sched/psi.c:933
#2: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#2: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#2: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: sched_balance_domains+0xe8/0x880 kernel/sched/fair.c:13987
#3: ffff8880b8724160 (tasklet_sync_callback.cb_lock.lock.wait_lock){....}-{2:2}, at: rt_mutex_slowunlock+0xbf/0xa30 kernel/locking/rtmutex.c:1430
#4: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#4: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#4: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#4: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e2/0x400 kernel/locking/spinlock_rt.c:57
#5: ffff888096651c58 (_T->lock){....}-{2:2}, at: rt_mutex_slowunlock+0xbf/0xa30 kernel/locking/rtmutex.c:1430
#6: ffff8880b87293d0 ((lock).lock.wait_lock#3){....}-{2:2}, at: rt_mutex_slowunlock+0xbf/0xa30 kernel/locking/rtmutex.c:1430
#7: ffff888096651cd8 (_T->lock){....}-{2:2}, at: rt_mutex_slowunlock+0xbf/0xa30 kernel/locking/rtmutex.c:1430
#8: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#8: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#8: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: __queue_work+0x225/0x1120 kernel/workqueue.c:2368
locks held by khungtaskd/38: 1, last CPU#0:
#0: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by kworker/u8:8/1113: 3, on CPU#0:
#0: ffff8880325c1138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff8880325c1138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff8880325c1138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff8880325c1138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc90006ad7c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90006ad7c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90006ad7c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc90006ad7c40 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#2: ffffffff8f5d3f78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#2: ffffffff8f5d3f78 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x123/0x16e0 net/ipv6/addrconf.c:4230
locks held by kworker/u8:18/2944: 5, last CPU#0:
#0: ffff888032875938 ((wq_completion)bat_events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888032875938 ((wq_completion)bat_events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888032875938 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff888032875938 ((wq_completion)bat_events){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc9000e8b7c40 ((work_completion)(&(&bat_priv->dat.work)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc9000e8b7c40 ((work_completion)(&(&bat_priv->dat.work)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc9000e8b7c40 ((work_completion)(&(&bat_priv->dat.work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc9000e8b7c40 ((work_completion)(&(&bat_priv->dat.work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#2: ffffffff8e059500 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3d/0x420 kernel/softirq.c:186
#3: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3d/0x420 kernel/softirq.c:186
#4: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#4: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#4: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
#4: ffffffff8e1c3c80 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e2/0x400 kernel/locking/spinlock_rt.c:57
locks held by getty/5347: 2, on CPU#1:
#0: ffff8880328090a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900044d62e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x460/0x1360 drivers/tty/n_tty.c:2211
locks held by kworker/1:9/10735: 3, on CPU#1:
#0: ffff88813ff27938 ((wq_completion)events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88813ff27938 ((wq_completion)events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88813ff27938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff88813ff27938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc900102e7c40 (deferred_process_work){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc900102e7c40 (deferred_process_work){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc900102e7c40 (deferred_process_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc900102e7c40 (deferred_process_work){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#2: ffffffff8f5d3f78 (rtnl_mutex){+.+.}-{4:4}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:104
locks held by kworker/u9:4/11812: 3, on CPU#0:
#0: ffff888066e27938 ((wq_completion)hci5){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888066e27938 ((wq_completion)hci5){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888066e27938 ((wq_completion)hci5){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff888066e27938 ((wq_completion)hci5){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc90004a9fc40 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90004a9fc40 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90004a9fc40 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc90004a9fc40 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#2: ffff88805fa90f80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x1cb/0x3f0 net/bluetooth/hci_sync.c:331
locks held by kworker/1:2/16382: 2, on CPU#1:
#0: ffff88813ff27938 ((wq_completion)events){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88813ff27938 ((wq_completion)events){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88813ff27938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#0: ffff88813ff27938 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
#1: ffffc90006b17c40 ((work_completion)(&dev->recv_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90006b17c40 ((work_completion)(&dev->recv_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90006b17c40 ((work_completion)(&dev->recv_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3361 [inline]
#1: ffffc90006b17c40 ((work_completion)(&dev->recv_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3479
locks held by syz.5.3077/20258: 3, on CPU#0:
#0: ffff8880358f1928 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff888050fd2510 (sb_writers#23){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff888050fd2510 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:867
locks held by syz.5.3077/20259: 3, on CPU#0:
#0: ffff88802fbf8728 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff888050fd2510 (sb_writers#23){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff888050fd2510 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3b4/0x610 fs/nfsd/nfsctl.c:436
locks held by syz.3.3093/20382: 3, on CPU#0:
#0: ffff8880604eb528 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff888061f50510 (sb_writers#23){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff888061f50510 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:708
locks held by syz.3.3093/20385: 3, on CPU#0:
#0: ffff888029e44128 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff888061f50510 (sb_writers#23){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff888061f50510 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:867
locks held by syz.3.3093/20386: 3, on CPU#1:
#0: ffff888029e44328 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff888061f50510 (sb_writers#23){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff888061f50510 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3b4/0x610 fs/nfsd/nfsctl.c:436
locks held by syz.4.3103/20433: 3, on CPU#0:
#0: ffff888033f79328 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff888036ed0510 (sb_writers#23){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff888036ed0510 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:708
locks held by syz.4.3103/20434: 3, on CPU#1:
#0: ffff888033bd1f28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff888036ed0510 (sb_writers#23){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff888036ed0510 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:867
locks held by syz.4.3103/20435: 3, on CPU#0:
#0: ffff888033f78d28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff888036ed0510 (sb_writers#23){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff888036ed0510 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3b4/0x610 fs/nfsd/nfsctl.c:436
locks held by syz-executor/20699: 2, on CPU#0:
#0: ffff88805e2ca0e0 (&type->s_umount_key#68){+.+.}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff88805e2ca0e0 (&type->s_umount_key#68){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff88805e2ca0e0 (&type->s_umount_key#68){+.+.}-{4:4}, at: deactivate_super+0xac/0xe0 fs/super.c:631
#1: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:582
locks held by syz.2.3163/20982: 3, on CPU#1:
#0: ffff88806078a128 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff88805e7dc510 (sb_writers#23){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff88805e7dc510 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:708
locks held by syz.2.3163/20983: 3, on CPU#1:
#0: ffff888059eba728 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff88805e7dc510 (sb_writers#23){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff88805e7dc510 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:867
locks held by syz.2.3163/20989: 3, on CPU#0:
#0: ffff888026abfb28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff88805e7dc510 (sb_writers#23){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff88805e7dc510 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3b4/0x610 fs/nfsd/nfsctl.c:436
locks held by syz-executor/21203: 2, on CPU#1:
#0: ffff88802c3880e0 (&type->s_umount_key#68){+.+.}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff88802c3880e0 (&type->s_umount_key#68){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff88802c3880e0 (&type->s_umount_key#68){+.+.}-{4:4}, at: deactivate_super+0xac/0xe0 fs/super.c:631
#1: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:582
locks held by syz.8.3199/21224: 2, on CPU#1:
#0: ffff88803fee40e0 (&type->s_umount_key#68){+.+.}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff88803fee40e0 (&type->s_umount_key#68){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff88803fee40e0 (&type->s_umount_key#68){+.+.}-{4:4}, at: deactivate_super+0xac/0xe0 fs/super.c:631
#1: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x4e/0xd0 fs/nfsd/nfssvc.c:582
locks held by syz.9.3228/21419: 3, on CPU#0:
#0: ffff8880557b2328 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff88802625e510 (sb_writers#23){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff88802625e510 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:708
locks held by syz.9.3228/21420: 3, on CPU#0:
#0: ffff8880557b3f28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff88802625e510 (sb_writers#23){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff88802625e510 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: write_ports+0xb5/0xd20 fs/nfsd/nfsctl.c:867
locks held by syz.9.3228/21422: 3, on CPU#1:
#0: ffff888062460d28 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff88802625e510 (sb_writers#23){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff88802625e510 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: write_threads+0x3b4/0x610 fs/nfsd/nfsctl.c:436
locks held by syz.6.3244/21519: 3, on CPU#1:
#0: ffff8880125e9528 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x252/0x320 fs/file.c:1259
#1: ffff888033390510 (sb_writers#23){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#1: ffff888033390510 (sb_writers#23){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#2: ffffffff8e4f8418 (nfsd_mutex){+.+.}-{4:4}, at: write_versions+0x95/0xe30 fs/nfsd/nfsctl.c:708
locks held by syz-executor/21751: 1, on CPU#1:
#0: ffffffff8f5d3f78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#0: ffffffff8f5d3f78 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x470/0x19f0 net/ipv4/devinet.c:978
locks held by kworker/u8:7/21757: 1, last CPU#0:
#0: ffff8880b863c320 (&rq->__lock){-...}-{2:2}, at: raw_spin_rq_lock_nested+0x2d/0x160 kernel/sched/core.c:677
locks held by syz-executor/21769: 1, on CPU#1:
#0: ffffffff8f5d3f78 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:134 [inline]
#0: ffffffff8f5d3f78 (rtnl_mutex){+.+.}-{4:4}, at: inet6_rtm_newaddr+0x667/0xe00 net/ipv6/addrconf.c:5063
locks held by syz-executor/22011: 8, last CPU#0:
#0: ffff888034a98510 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2753 [inline]
#0: ffff888034a98510 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x231/0xbb0 fs/read_write.c:683
#1: ffff888092a33878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1d9/0x540 fs/kernfs/file.c:336
#2: ffff8880297e2788 (kn->active#51){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:73 [inline]
#2: ffff8880297e2788 (kn->active#51){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x22c/0x540 fs/kernfs/file.c:337
#3: ffffffff8ee44818 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd6/0x370 drivers/net/netdevsim/bus.c:234
#4: ffff88802c677160 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1104 [inline]
#4: ffff88802c677160 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1171 [inline]
#4: ffff88802c677160 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb9/0x880 drivers/base/dd.c:1369
#5: ffff88802a302310 (&devlink->lock_key#37){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x160 drivers/net/netdevsim/dev.c:1724
#6: ffffffff8f5d3f78 (rtnl_mutex){+.+.}-{4:4}, at: nsim_destroy+0x173/0x800 drivers/net/netdevsim/netdev.c:1193
#7: ffff888071109060 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_lock include/linux/netdevice.h:2861 [inline]
#7: ffff888071109060 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: netdev_lock_ops include/net/netdev_lock.h:42 [inline]
#7: ffff888071109060 (&dev_instance_lock_key#23){+.+.}-{4:4}, at: unregister_netdevice_many_notify+0x11d0/0x2130 net/core/dev.c:12504
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
trigger_all_cpu_backtrace include/linux/nmi.h:164 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
watchdog+0xfd7/0x1030 kernel/hung_task.c:561
kthread+0x38b/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 17 Comm: pr/ttyS0 Tainted: G L syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:409
Code: e8 6e fc 64 fc 44 89 f9 d3 e3 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 5f e7 d0 fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07
RSP: 0018:ffffc900001678b8 EFLAGS: 00000202
RAX: 1ffffffff33d4400 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff85619c70 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff99ea2220 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888125ccb000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f83f609b840 CR3: 000000003fd02000 CR4: 00000000003526f0
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:128 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline]
wait_for_lsr+0x190/0x300 drivers/tty/serial/8250/8250_port.c:2013
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3270 [inline]
__serial8250_console_fifo_write+0xd0/0x3f0 drivers/tty/serial/8250/8250_port.c:3345
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3378 [inline]
__serial8250_console_write drivers/tty/serial/8250/8250_port.c:3429 [inline]
serial8250_console_write+0xac5/0x1230 drivers/tty/serial/8250/8250_port.c:3493
nbcon_emit_next_record+0xef5/0x1a90 kernel/printk/nbcon.c:-1
nbcon_emit_one kernel/printk/nbcon.c:1157 [inline]
nbcon_kthread_func+0x679/0x880 kernel/printk/nbcon.c:1271
kthread+0x38b/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245