INFO: task syz.1.312:7344 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.312 state:D stack:27408 pid:7344 tgid:7334 ppid:5844 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5352 [inline] __schedule+0x1665/0x5590 kernel/sched/core.c:6964 __schedule_loop kernel/sched/core.c:7047 [inline] schedule+0x164/0x360 kernel/sched/core.c:7062 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7119 rwsem_down_write_slowpath+0x883/0x1080 kernel/locking/rwsem.c:1215 __down_write_common kernel/locking/rwsem.c:1347 [inline] __down_write kernel/locking/rwsem.c:1356 [inline] down_write+0x1bc/0x200 kernel/locking/rwsem.c:1626 mmap_write_lock include/linux/mmap_lock.h:536 [inline] do_mbind mm/mempolicy.c:1529 [inline] kernel_mbind mm/mempolicy.c:1751 [inline] __do_sys_mbind mm/mempolicy.c:1825 [inline] __se_sys_mbind+0x995/0x10f0 mm/mempolicy.c:1821 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: 0033:0x7f4edbf9c799 RSP: 002b:00007f4eda1d5028 EFLAGS: 00000246 ORIG_RAX: 00000000000000ed RAX: ffffffffffffffda RBX: 00007f4edc216180 RCX: 00007f4edbf9c799 RDX: 0000000000000000 RSI: 0000000000800000 RDI: 0000200000001000 RBP: 00007f4edc032c99 R08: 0000000000000000 R09: 0000000000000002 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f4edc216218 R14: 00007f4edc216180 R15: 00007ffe00ff8828 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e75d6a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8e75d6a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8e75d6a0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:5/99: #0: ffff88801b0ac140 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x894/0x1780 kernel/workqueue.c:3261 #1: ffffc90002527c40 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x8bb/0x1780 kernel/workqueue.c:3262 #2: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313 2 locks held by getty/5596: #0: ffff88803328e0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000322b2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45c/0x13c0 drivers/tty/n_tty.c:2211 1 lock held by syz.1.312/7344: #0: ffff8880338c41b8 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:536 [inline] #0: ffff8880338c41b8 (&mm->mmap_lock){++++}-{4:4}, at: do_mbind mm/mempolicy.c:1529 [inline] #0: ffff8880338c41b8 (&mm->mmap_lock){++++}-{4:4}, at: kernel_mbind mm/mempolicy.c:1751 [inline] #0: ffff8880338c41b8 (&mm->mmap_lock){++++}-{4:4}, at: __do_sys_mbind mm/mempolicy.c:1825 [inline] #0: ffff8880338c41b8 (&mm->mmap_lock){++++}-{4:4}, at: __se_sys_mbind+0x995/0x10f0 mm/mempolicy.c:1821 2 locks held by syz.6.821/9418: #0: ffffffff8fbc6d68 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:577 #1: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: fib_net_exit_batch+0x22/0xf0 net/ipv4/fib_frontend.c:1676 2 locks held by syz.8.820/9427: #0: ffffffff8fbc6d68 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:577 #1: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: caif_exit_net+0x6a/0x4b0 net/caif/caif_dev.c:528 1 lock held by syz.7.829/9443: #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: ip_mroute_setsockopt+0x137/0x1090 net/ipv4/ipmr.c:1409 2 locks held by syz.5.828/9444: #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline] #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x3e/0x1c0 drivers/net/tun.c:3436 #1: ffffffff8e7638e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #1: ffffffff8e7638e8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2d0/0x770 kernel/rcu/tree_exp.h:961 1 lock held by syz.4.832/9468: #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: __tun_chr_ioctl+0x3bc/0x1e30 drivers/net/tun.c:3078 2 locks held by syz.4.832/9469: #0: ffff88802a8b26e8 (nlk_cb_mutex-ROUTE){+.+.}-{4:4}, at: __netlink_dump_start+0xfe/0x7e0 net/netlink/af_netlink.c:2404 #1: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dumpit+0x92/0x200 net/core/rtnetlink.c:6826 1 lock held by syz.4.832/9472: #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8fbd5d80 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4071 ============================================= 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:162 [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+0x1002/0x1060 kernel/hung_task.c:561 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: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:63 Code: ed 6a 02 e9 d3 f1 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d b3 e1 14 00 fb f4 cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 RSP: 0018:ffffffff8e407dc0 EFLAGS: 00000246 RAX: 0000000000394a8b RBX: ffffffff819b946a RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8df3af0d RDI: ffffffff8c284e00 RBP: ffffffff8e407eb0 R08: ffff8880b863399b R09: 1ffff110170c6733 R10: dffffc0000000000 R11: ffffed10170c6734 R12: 0000000000000000 R13: 1ffffffff1c925d8 R14: 0000000000000000 R15: 1ffffffff1c925d8 FS: 0000000000000000(0000) GS:ffff888125435000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055ddf19cda38 CR3: 000000007e4ee000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/kernel/process.c:766 [inline] default_idle+0x9/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x72/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x36a/0x5f0 kernel/sched/idle.c:352 cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:451 rest_init+0x2de/0x300 init/main.c:762 start_kernel+0x38f/0x3e0 init/main.c:1214 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x143/0x1c0 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x147