INFO: task syz.0.17:6030 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.17 state:D stack:26312 pid:6030 tgid:6025 ppid:5955 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5325 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6929 __schedule_loop kernel/sched/core.c:7011 [inline] schedule+0x165/0x360 kernel/sched/core.c:7026 request_wait_answer fs/fuse/dev.c:585 [inline] __fuse_request_send fs/fuse/dev.c:599 [inline] __fuse_simple_request+0x11cc/0x1bb0 fs/fuse/dev.c:693 fuse_simple_request fs/fuse/fuse_i.h:1250 [inline] fuse_do_setattr+0xfa6/0x1a20 fs/fuse/dir.c:2038 fuse_setattr+0x537/0xae0 fs/fuse/dir.c:2159 notify_change+0xc1a/0xf40 fs/attr.c:546 chmod_common+0x248/0x400 fs/open.c:650 do_fchmodat+0x12d/0x200 fs/open.c:697 __do_sys_chmod fs/open.c:721 [inline] __se_sys_chmod fs/open.c:719 [inline] __x64_sys_chmod+0x62/0x70 fs/open.c:719 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa1e3d8eec9 RSP: 002b:00007fa1e4b3f038 EFLAGS: 00000246 ORIG_RAX: 000000000000005a RAX: ffffffffffffffda RBX: 00007fa1e3fe6090 RCX: 00007fa1e3d8eec9 RDX: 0000000000000000 RSI: 00000000000003ca RDI: 0000200000000100 RBP: 00007fa1e3e11f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa1e3fe6128 R14: 00007fa1e3fe6090 R15: 00007ffe5f255f08 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e13d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e13d2e0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e13d2e0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:2/36: #0: ffff88814cb3f148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88814cb3f148 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc90000ac7ba0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc90000ac7ba0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffffffff8f4e65c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8f4e65c8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x112/0x14b0 net/ipv6/addrconf.c:4194 2 locks held by getty/5583: #0: ffff88814d6e50a0 (&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+0x43e/0x1400 drivers/tty/n_tty.c:2222 2 locks held by syz.0.17/6030: #0: ffff88807adaa420 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:508 #1: ffff88805d0a0148 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: inode_lock_killable include/linux/fs.h:985 [inline] #1: ffff88805d0a0148 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: chmod_common+0x161/0x400 fs/open.c:642 2 locks held by syz.1.18/6068: #0: ffff888078be8420 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:508 #1: ffff88805d290148 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: inode_lock_killable include/linux/fs.h:985 [inline] #1: ffff88805d290148 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: chmod_common+0x161/0x400 fs/open.c:642 2 locks held by syz.2.19/6092: #0: ffff88807a684420 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:508 #1: ffff88805d290848 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: inode_lock_killable include/linux/fs.h:985 [inline] #1: ffff88805d290848 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: chmod_common+0x161/0x400 fs/open.c:642 2 locks held by syz.3.20/6116: #0: ffff888032ef0420 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:508 #1: ffff88805d0a0848 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: inode_lock_killable include/linux/fs.h:985 [inline] #1: ffff88805d0a0848 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: chmod_common+0x161/0x400 fs/open.c:642 2 locks held by syz.4.21/6152: #0: ffff888028fbc420 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:508 #1: ffff88805d0a0f48 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: inode_lock_killable include/linux/fs.h:985 [inline] #1: ffff88805d0a0f48 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: chmod_common+0x161/0x400 fs/open.c:642 2 locks held by syz.5.22/6182: #0: ffff88802f032420 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:508 #1: ffff88805d290f48 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: inode_lock_killable include/linux/fs.h:985 [inline] #1: ffff88805d290f48 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: chmod_common+0x161/0x400 fs/open.c:642 2 locks held by syz.6.23/6213: #0: ffff888056e00420 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:508 #1: ffff88805d0a1648 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: inode_lock_killable include/linux/fs.h:985 [inline] #1: ffff88805d0a1648 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: chmod_common+0x161/0x400 fs/open.c:642 3 locks held by kworker/1:5/6214: #0: ffff88813fe55948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline] #0: ffff88813fe55948 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346 #1: ffffc90003fffba0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline] #1: ffffc90003fffba0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346 #2: ffff88802f2d1240 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x1f7/0x3b0 drivers/net/netdevsim/fib.c:1490 2 locks held by syz.7.24/6243: #0: ffff888057ce4420 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:508 #1: ffff88805d0a1d48 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: inode_lock_killable include/linux/fs.h:985 [inline] #1: ffff88805d0a1d48 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: chmod_common+0x161/0x400 fs/open.c:642 2 locks held by syz.8.25/6280: #0: ffff888057824420 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:508 #1: ffff88805d291648 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: inode_lock_killable include/linux/fs.h:985 [inline] #1: ffff88805d291648 (&type->i_mutex_dir_key#8){+.+.}-{4:4}, at: chmod_common+0x161/0x400 fs/open.c:642 3 locks held by syz-executor/6283: #0: ffffffff8f4e65c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8f4e65c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8f4e65c8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8e9/0x1c80 net/core/rtnetlink.c:4064 #1: ffff8880585c9528 (&wg->device_update_lock){+.+.}-{4:4}, at: wg_open+0x227/0x420 drivers/net/wireguard/device.c:50 #2: ffffffff8e142d78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #2: ffffffff8e142d78 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2f6/0x730 kernel/rcu/tree_exp.h:957 ============================================= 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 10/02/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:337 [inline] watchdog+0xfa9/0xff0 kernel/hung_task.c:500 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x4bc/0x870 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 10/02/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: cc cc cc cc 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 53 31 21 00 f3 0f 1e fa fb f4 48 e7 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffffff8de07d80 EFLAGS: 000002c6 RAX: a4734a5603ae2300 RBX: ffffffff8196d367 RCX: a4734a5603ae2300 RDX: 0000000000000001 RSI: ffffffff8d7f7453 RDI: ffffffff8bc0d6e0 RBP: ffffffff8de07ea8 R08: ffff8880b8632fdb R09: 1ffff110170c65fb R10: dffffc0000000000 R11: ffffed10170c65fc R12: ffffffff8f9dd670 R13: 0000000000000000 R14: 0000000000000000 R15: 1ffffffff1bd2a40 FS: 0000000000000000(0000) GS:ffff888125d22000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fac2091e790 CR3: 000000000df38000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:190 [inline] do_idle+0x1e7/0x510 kernel/sched/idle.c:330 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428 rest_init+0x2de/0x300 init/main.c:757 start_kernel+0x3ae/0x410 init/main.c:1111 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