INFO: task syz.0.144:7043 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.0.144 state:D stack:25624 pid:7043 tgid:7025 ppid:5807 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5260 [inline] __schedule+0x1472/0x4fe0 kernel/sched/core.c:6867 __schedule_loop kernel/sched/core.c:6949 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7245 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:244 inode_lock_nested include/linux/fs.h:1072 [inline] __start_dirop fs/namei.c:2873 [inline] start_dirop fs/namei.c:2884 [inline] filename_create+0x200/0x370 fs/namei.c:4888 do_mkdirat+0xd2/0x4c0 fs/namei.c:5165 __do_sys_mkdirat fs/namei.c:5195 [inline] __se_sys_mkdirat fs/namei.c:5193 [inline] __x64_sys_mkdirat+0x87/0xa0 fs/namei.c:5193 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: 0033:0x7f489ffe9d97 RSP: 002b:00007f489e224e58 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f489e224ee0 RCX: 00007f489ffe9d97 RDX: 00000000000001ff RSI: 00002000000000c0 RDI: 00000000ffffff9c RBP: 0000000000000000 R08: 0000200000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00002000000000c0 R13: 00007f489e224ea0 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by khungtaskd/38: #0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 6 locks held by kworker/u8:4/68: #0: ffff88801aad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88801aad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340 #0: ffff88801aad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88801aad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340 #1: ffffc9000153fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc9000153fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340 #2: ffffffff8ef2cae0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xfe/0x7b0 net/core/net_namespace.c:670 #3: ffff88803a29f0d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline] #3: ffff88803a29f0d8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline] #3: ffff88803a29f0d8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x117/0x3f0 net/devlink/core.c:506 #4: ffff88805d6c0300 (&devlink->lock_key#10){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:276 [inline] #4: ffff88805d6c0300 (&devlink->lock_key#10){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline] #4: ffff88805d6c0300 (&devlink->lock_key#10){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x129/0x3f0 net/devlink/core.c:506 #5: ffffffff8ef3b3f8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #5: ffffffff8ef3b3f8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x257/0x2f0 net/core/dev.c:2156 4 locks held by kworker/u8:5/160: #0: ffff88814047c938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88814047c938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340 #1: ffffc90003b47bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc90003b47bc0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340 #2: ffff88802499c0d0 (&type->s_umount_key#84){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563 #3: ffff88805e8bd9a8 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108 2 locks held by dhcpcd/5458: #0: ffff88805cfdc928 (nlk_cb_mutex-ROUTE){+.+.}-{4:4}, at: netlink_dump+0xe4/0xe80 net/netlink/af_netlink.c:2267 #1: ffffffff8ef3b3f8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8ef3b3f8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_dumpit+0x92/0x200 net/core/rtnetlink.c:6826 2 locks held by getty/5557: #0: ffff88814e15a0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e7e2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211 4 locks held by syz.0.144/7030: 2 locks held by syz.0.144/7043: #0: ffff88802499c480 (sb_writers#27){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499 #1: ffff88805e8bdd78 (&type->i_mutex_dir_key#19/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1072 [inline] #1: ffff88805e8bdd78 (&type->i_mutex_dir_key#19/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2873 [inline] #1: ffff88805e8bdd78 (&type->i_mutex_dir_key#19/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2884 [inline] #1: ffff88805e8bdd78 (&type->i_mutex_dir_key#19/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:4888 2 locks held by syz.5.217/7612: #0: ffff88802499c0d0 (&type->s_umount_key#84){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff88802499c0d0 (&type->s_umount_key#84){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:121 #1: ffff8880257508c0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:397 [inline] #1: ffff8880257508c0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x1c5/0xc10 fs/fs-writeback.c:2905 3 locks held by kworker/u8:14/8267: #0: ffff88813fe69938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88813fe69938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340 #1: ffffc90005167bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc90005167bc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340 #2: ffffffff8ef3b3f8 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:313 8 locks held by syz-executor/8309: 4 locks held by syz-executor/8355: #0: ffff888035f7c480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2683 [inline] #0: ffff888035f7c480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:682 #1: ffff888032b81878 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343 #2: ffff888143b30968 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff888143b30968 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x540 fs/kernfs/file.c:344 #3: ffffffff8e7aa858 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234 1 lock held by syz-executor/8424: #0: ffffffff8ef3b3f8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8ef3b3f8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8ef3b3f8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4071 2 locks held by syz-executor/8444: #0: ffffffff8e6988a8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8e6988a8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8e6988a8 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8ef3b3f8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8ef3b3f8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8ef3b3f8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8a1/0x1be0 net/core/rtnetlink.c:4071 3 locks held by syz.6.341/8484: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 5458 Comm: dhcpcd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:skb_put+0xfb/0x210 net/core/skbuff.c:2622 Code: 70 48 89 f8 48 c1 e8 03 0f b6 04 10 84 c0 0f 85 df 00 00 00 45 01 6e 70 4d 8d a6 cc 00 00 00 4c 89 e0 48 c1 e8 03 0f b6 04 10 <84> c0 0f 85 e5 00 00 00 45 8b 24 24 89 ef 44 89 e6 e8 cf a2 e7 f8 RSP: 0018:ffffc90003f26e80 EFLAGS: 00000a03 RAX: 0000000000000000 RBX: 0000000000002bbc RCX: ffff888031f9bc80 RDX: dffffc0000000000 RSI: 0000000000000000 RDI: ffff8880579e2430 RBP: 0000000000002bc4 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffed100bea1d78 R12: ffff8880579e248c R13: 0000000000000008 R14: ffff8880579e23c0 R15: ffff88805f50c000 FS: 00007f382be18740(0000) GS:ffff8881265c9000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055558dbf1a68 CR3: 000000002a900000 CR4: 00000000003526f0 Call Trace: __nla_reserve lib/nlattr.c:906 [inline] __nla_put+0x3a/0xd0 lib/nlattr.c:1040 nla_put+0xd0/0x150 lib/nlattr.c:1099 nla_put_u32 include/net/netlink.h:1459 [inline] rtnl_fill_ifinfo+0xc35/0x20f0 net/core/rtnetlink.c:2077 rtnl_dump_ifinfo+0xbb1/0x1180 net/core/rtnetlink.c:2514 rtnl_dumpit+0xa2/0x200 net/core/rtnetlink.c:6827 netlink_dump+0x722/0xe80 net/netlink/af_netlink.c:2325 netlink_recvmsg+0x690/0xa50 net/netlink/af_netlink.c:1976 sock_recvmsg_nosec net/socket.c:1078 [inline] sock_recvmsg+0x22c/0x270 net/socket.c:1100 ____sys_recvmsg+0x1f2/0x4b0 net/socket.c:2812 ___sys_recvmsg+0x215/0x590 net/socket.c:2854 __sys_recvmsg net/socket.c:2887 [inline] __do_sys_recvmsg net/socket.c:2893 [inline] __se_sys_recvmsg net/socket.c:2890 [inline] __x64_sys_recvmsg+0x1c0/0x2a0 net/socket.c:2890 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: 0033:0x7f382bea2407 Code: 48 89 fa 4c 89 df e8 38 aa 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff RSP: 002b:00007ffe908c5040 EFLAGS: 00000202 ORIG_RAX: 000000000000002f RAX: ffffffffffffffda RBX: 00007f382be18740 RCX: 00007f382bea2407 RDX: 0000000000000000 RSI: 00007ffe908c50d0 RDI: 000000000000002c RBP: 00007ffe908c50b4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000001f40 R13: 00007ffe908c50c0 R14: 00007ffe908c51b0 R15: 0000000000000000