INFO: task syz.1.6867:31125 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.6867 state:D stack:27104 pid:31125 tgid:31124 ppid:26382 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0x14ea/0x5050 kernel/sched/core.c:6867 __schedule_loop kernel/sched/core.c:6949 [inline] schedule+0x164/0x360 kernel/sched/core.c:6964 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7021 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0x7fe/0x1300 kernel/locking/mutex.c:776 nfsd_nl_threads_get_doit+0x1ba/0x700 fs/nfsd/nfsctl.c:1678 genl_family_rcv_msg_doit+0x22a/0x330 net/netlink/genetlink.c:1115 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0x61c/0x7a0 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] ____sys_sendmsg+0xa68/0xad0 net/socket.c:2592 ___sys_sendmsg+0x2a5/0x360 net/socket.c:2646 __sys_sendmsg net/socket.c:2678 [inline] __do_sys_sendmsg net/socket.c:2683 [inline] __se_sys_sendmsg net/socket.c:2681 [inline] __x64_sys_sendmsg+0x1bd/0x2a0 net/socket.c:2681 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7ab379aeb9 RSP: 002b:00007f7ab46d9028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f7ab3a15fa0 RCX: 00007f7ab379aeb9 RDX: 0000000024048000 RSI: 0000200000000000 RDI: 0000000000000006 RBP: 00007f7ab3808c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f7ab3a16038 R14: 00007f7ab3a15fa0 R15: 00007ffcffe88ff8 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5586: #0: ffff88814e5100a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000363b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211 4 locks held by kworker/u8:21/20628: #0: ffff8880b873a918 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:639 #1: ffff8880b8724588 (psi_seq){-.-.}-{0:0}, at: psi_task_switch+0x53/0x880 kernel/sched/psi.c:933 #2: ffff88805dc80788 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: class_wiphy_constructor include/net/cfg80211.h:6360 [inline] #2: ffff88805dc80788 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: cfg80211_wiphy_work+0xb4/0x450 net/wireless/core.c:424 #3: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #3: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #3: ffffffff8e55a360 (rcu_read_lock){....}-{1:3}, at: ieee80211_sta_active_ibss+0xc3/0x330 net/mac80211/ibss.c:635 2 locks held by syz.0.5116/24746: #0: ffffffff8fa1a130 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e879368 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x141/0x16c0 fs/nfsd/nfsctl.c:1886 2 locks held by syz.1.6867/31125: #0: ffffffff8fa1a130 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e879368 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_get_doit+0x1ba/0x700 fs/nfsd/nfsctl.c:1678 2 locks held by syz.6.7536/1100: #0: ffffffff8fa1a130 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e879368 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_get_doit+0x1ba/0x700 fs/nfsd/nfsctl.c:1678 2 locks held by syz.5.8044/3069: #0: ffffffff8fa1a130 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e879368 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_get_doit+0x10a/0x5e0 fs/nfsd/nfsctl.c:2036 2 locks held by syz.4.8202/3606: #0: ffffffff8fa1a130 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8e879368 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_version_set_doit+0xcd/0x7a0 fs/nfsd/nfsctl.c:1736 7 locks held by syz-executor/4106: #0: ffff88803388a420 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2683 [inline] #0: ffff88803388a420 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x227/0xb90 fs/read_write.c:682 #1: ffff88814dd03c88 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1de/0x540 fs/kernfs/file.c:343 #2: ffff88802758fa58 (kn->active#53){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff88802758fa58 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x231/0x540 fs/kernfs/file.c:344 #3: ffffffff8f222548 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: new_device_store+0x13c/0x710 drivers/net/netdevsim/bus.c:184 #4: ffff8880298720e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #4: ffff8880298720e8 (&dev->mutex){....}-{4:4}, at: __device_attach+0x88/0x450 drivers/base/dd.c:1008 #5: ffff888029870250 (&devlink->lock_key#19){+.+.}-{4:4}, at: nsim_drv_probe+0xc9/0xc20 drivers/net/netdevsim/dev.c:1637 #6: ffffffff8f9ac088 (rtnl_mutex){+.+.}-{4:4}, at: register_nexthop_notifier+0x88/0x290 net/ipv4/nexthop.c:3971 1 lock held by syz.8.8384/4255: #0: ffffffff8e560b40 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x4c/0x580 kernel/rcu/tree.c:3816 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:161 [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:346 [inline] watchdog+0xf90/0xfe0 kernel/hung_task.c:515 kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 12309 Comm: kworker/1:10 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 Workqueue: 0x0 (rcu_gp) RIP: 0010:move_linked_works kernel/workqueue.c:1148 [inline] RIP: 0010:assign_work kernel/workqueue.c:-1 [inline] RIP: 0010:worker_thread+0xd68/0x1360 kernel/workqueue.c:3420 Code: 49 bc 00 00 00 00 00 fc ff df 4c 89 e8 48 c1 e8 03 42 80 3c 20 00 4c 8b 7c 24 28 74 08 4c 89 ef e8 1d b2 9e 00 41 f6 45 00 08 <74> 15 4c 8d 6b f8 e8 cd 65 36 00 e9 1f fe ff ff e8 c3 65 36 00 eb RSP: 0018:ffffc900039cfc80 EFLAGS: 00000046 RAX: 1ffff11003956a5a RBX: ffff8880b873a0e0 RCX: dffffc0000000000 RDX: 0000000000000000 RSI: ffff888031e19440 RDI: ffff88801cab52d8 RBP: ffff88801cab52d8 R08: ffff888031e19427 R09: 0000000000000000 R10: ffff888031e19410 R11: ffffed10063c3285 R12: dffffc0000000000 R13: ffff88801cab52d0 R14: 0000000000000000 R15: ffff88802b0317b8 FS: 0000000000000000(0000) GS:ffff8881257f5000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fee4ff435c0 CR3: 000000007d8f6000 CR4: 00000000003526f0 Call Trace: kthread+0x726/0x8b0 kernel/kthread.c:463 ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246