INFO: task syz.4.2860:16190 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.2860 state:D stack:27040 pid:16190 tgid:16189 ppid:5832 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0x164/0x360 kernel/sched/core.c:7008 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065 __mutex_lock_common kernel/locking/mutex.c:692 [inline] __mutex_lock+0x7fe/0x1300 kernel/locking/mutex.c:776 nfsd_nl_threads_get_doit+0x1c0/0x790 fs/nfsd/nfsctl.c:1693 genl_family_rcv_msg_doit+0x22a/0x330 net/netlink/genetlink.c:1114 genl_family_rcv_msg net/netlink/genetlink.c:1194 [inline] genl_rcv_msg+0x61c/0x7a0 net/netlink/genetlink.c:1209 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1218 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+0x972/0x9f0 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+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5c67d9c799 RSP: 002b:00007f5c68cec028 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f5c68015fa0 RCX: 00007f5c67d9c799 RDX: 0000000024048000 RSI: 0000200000000000 RDI: 0000000000000003 RBP: 00007f5c67e32c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f5c68016038 R14: 00007f5c68015fa0 R15: 00007fff4eed6ae8 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8e75e620 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by getty/5582: #0: ffff88803264e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211 3 locks held by kworker/0:4/5882: #0: ffff88813fe0f148 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #0: ffff88813fe0f148 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0xa52/0x18c0 kernel/workqueue.c:3359 #1: ffffc90003c57c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3252 [inline] #1: ffffc90003c57c40 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa8d/0x18c0 kernel/workqueue.c:3359 #2: ffff888075754240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x202/0x3d0 drivers/net/netdevsim/fib.c:1490 2 locks held by syz.3.1719/12289: #0: ffffffff8fc3cf30 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8ea86788 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_listener_set_doit+0x141/0x1670 fs/nfsd/nfsctl.c:1903 2 locks held by syz.4.2860/16190: #0: ffffffff8fc3cf30 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217 #1: ffffffff8ea86788 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_get_doit+0x1c0/0x790 fs/nfsd/nfsctl.c:1693 1 lock held by syz.1.4736/22965: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 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+0xfd9/0x1030 kernel/hung_task.c:515 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 22965 Comm: syz.1.4736 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:unwind_next_frame+0x1ab9/0x23c0 arch/x86/kernel/unwind_orc.c:695 Code: 48 c7 c2 80 a3 c9 8b e8 c5 3c 2b 00 48 c7 c7 20 e6 75 8e 4c 89 fe e8 36 23 2b 00 e8 11 de 34 00 89 d8 48 81 c4 98 00 00 00 5b <41> 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc cc 4c 8b 7c 24 50 eb 89 RSP: 0018:ffffc90000007818 EFLAGS: 00000092 RAX: 0000000090a63001 RBX: ffffc90000007900 RCX: 0000000000000101 RDX: 0000000000000005 RSI: ffffffff8e16a5d7 RDI: ffff8880361f8000 RBP: dffffc0000000000 R08: ffffc900033c6b28 R09: 0000000000000000 R10: ffffc90000007898 R11: fffff52000000f15 R12: ffffc900033c6b38 R13: ffffc900033c0000 R14: ffffc90000007848 R15: ffffffff81767e95 FS: 0000000000000000(0000) GS:ffff88812545a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000200001000000 CR3: 0000000076e68000 CR4: 00000000003526f0 Call Trace: arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556 insert_work+0x3d/0x330 kernel/workqueue.c:2199 __queue_work+0xbe1/0x1020 kernel/workqueue.c:2358 call_timer_fn+0x192/0x640 kernel/time/timer.c:1748 expire_timers kernel/time/timer.c:1794 [inline] __run_timers kernel/time/timer.c:2373 [inline] __run_timer_base+0x67e/0x8b0 kernel/time/timer.c:2385 run_timer_base kernel/time/timer.c:2394 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2404 handle_softirqs+0x22a/0x870 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x5f/0x150 kernel/softirq.c:723 irq_exit_rcu+0x9/0x30 kernel/softirq.c:739 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:on_stack arch/x86/include/asm/stacktrace.h:56 [inline] RIP: 0010:stack_access_ok arch/x86/kernel/unwind_orc.c:409 [inline] RIP: 0010:deref_stack_reg+0x63/0x230 arch/x86/kernel/unwind_orc.c:419 Code: 48 89 df e8 7f 52 b9 00 4c 8b 04 24 48 be 00 00 00 00 00 fc ff df 48 89 5c 24 10 49 8b 5f 08 4d 8d 77 10 4d 89 f5 49 c1 ed 03 <41> 80 7c 35 00 00 74 16 4c 89 f7 e8 4d 52 b9 00 4c 8b 04 24 48 be RSP: 0018:ffffc900033c6ae0 EFLAGS: 00000a02 RAX: fffffffffffffff0 RBX: ffffc900033c0000 RCX: 0000000000000000 RDX: ffffc900033c6c48 RSI: dffffc0000000000 RDI: ffffc900033c6c08 RBP: dffffc0000000000 R08: ffffc900033c7c80 R09: 0000000000000000 R10: ffffc900033c6c58 R11: fffff52000678d8d R12: 1ffff92000678d82 R13: 1ffff92000678d83 R14: ffffc900033c6c18 R15: ffffc900033c6c08 unwind_next_frame+0x18c6/0x23c0 arch/x86/kernel/unwind_orc.c:-1 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:165 __reset_page_owner+0x71/0x1f0 mm/page_owner.c:320 reset_page_owner include/linux/page_owner.h:25 [inline] __free_pages_prepare mm/page_alloc.c:1433 [inline] free_unref_folios+0xed5/0x16d0 mm/page_alloc.c:3040 folios_put_refs+0x789/0x8d0 mm/swap.c:1002 free_pages_and_swap_cache+0x2e7/0x5b0 mm/swap_state.c:423 __tlb_batch_free_encoded_pages mm/mmu_gather.c:138 [inline] tlb_batch_pages_flush mm/mmu_gather.c:151 [inline] tlb_flush_mmu_free mm/mmu_gather.c:398 [inline] tlb_flush_mmu+0x6d3/0xa30 mm/mmu_gather.c:405 zap_pte_range mm/memory.c:1968 [inline] zap_pmd_range mm/memory.c:2021 [inline] zap_pud_range mm/memory.c:2049 [inline] zap_p4d_range mm/memory.c:2070 [inline] unmap_page_range+0x3c1d/0x48f0 mm/memory.c:2091 unmap_single_vma mm/memory.c:2133 [inline] unmap_vmas+0x48f/0x6a0 mm/memory.c:2171 exit_mmap+0x280/0xa10 mm/mmap.c:1302 __mmput+0x118/0x430 kernel/fork.c:1175 exit_mm+0x168/0x220 kernel/exit.c:581 do_exit+0x6a2/0x23c0 kernel/exit.c:964 do_group_exit+0x21b/0x2d0 kernel/exit.c:1118 get_signal+0x1284/0x1330 kernel/signal.c:3034 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa39e39c799 Code: Unable to access opcode bytes at 0x7fa39e39c76f. RSP: 002b:00007fa39f29e0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca RAX: fffffffffffffe00 RBX: 00007fa39e616188 RCX: 00007fa39e39c799 RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fa39e616188 RBP: 00007fa39e616180 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa39e616218 R14: 00007fffd30a9400 R15: 00007fffd30a94e8