INFO: task syz.4.324:5529 blocked for more than 143 seconds. Not tainted 6.1.132-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.324 state:D stack:17368 pid:5529 ppid:4256 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5244 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6561 schedule+0xbf/0x180 kernel/sched/core.c:6637 wb_wait_for_completion+0x162/0x290 fs/fs-writeback.c:191 sync_inodes_sb+0x28f/0xb10 fs/fs-writeback.c:2739 sync_filesystem+0x16b/0x220 fs/sync.c:64 generic_shutdown_super+0x6b/0x340 fs/super.c:474 kill_block_super+0x7a/0xe0 fs/super.c:1470 deactivate_locked_super+0xa0/0x110 fs/super.c:332 cleanup_mnt+0x490/0x520 fs/namespace.c:1186 task_work_run+0x246/0x300 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0xa6e/0x26a0 kernel/exit.c:871 do_group_exit+0x202/0x2b0 kernel/exit.c:1021 get_signal+0x16cb/0x17a0 kernel/signal.c:2871 arch_do_signal_or_restart+0xb0/0x1a10 arch/x86/kernel/signal.c:871 exit_to_user_mode_loop+0x6a/0x100 kernel/entry/common.c:174 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fe56458d169 RSP: 002b:00007fe5643de038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffff8b RBX: 00007fe5647a6160 RCX: 00007fe56458d169 RDX: 0000000000000009 RSI: 000000000060000b RDI: 0000200000000000 RBP: 00007fe56460e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007fe5647a6160 R15: 00007ffd88bc2a68 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8d32e910 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffffffff8d32f110 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517 1 lock held by khungtaskd/28: #0: ffffffff8d32e740 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8d32e740 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8d32e740 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6510 5 locks held by kworker/u4:2/33: #0: ffff888017e16938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #1: ffffc90000a9fd20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #2: ffffffff8e543c50 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x166/0xd20 net/core/net_namespace.c:594 #3: ffffffff8e5507a8 (rtnl_mutex){+.+.}-{3:3}, at: default_device_exit_batch+0xe5/0xa20 net/core/dev.c:11477 #4: ffffffff8d333d78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline] #4: ffffffff8d333d78 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x4f0/0x930 kernel/rcu/tree_exp.h:962 4 locks held by udevd/3623: #0: ffff88805dc4e9e0 ( &p->lock ){+.+.}-{3:3} , at: seq_read_iter+0xae/0xd10 fs/seq_file.c:182 #1: ffff8880282bd888 (&of->mutex){+.+.}-{3:3}, at: kernfs_seq_start+0x4f/0x3a0 fs/kernfs/file.c:154 #2: ffff8880737d2490 (kn->active#5){++++}-{0:0}, at: kernfs_seq_start+0x6e/0x3a0 fs/kernfs/file.c:155 #3: ffff88807d67d0e8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline] #3: ffff88807d67d0e8 (&dev->mutex){....}-{3:3}, at: uevent_show+0x176/0x330 drivers/base/core.c:2669 2 locks held by dhcpcd/3916: #0: ffffffff8e5b17f0 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:860 #1: ffffffff8e5b16a8 (genl_mutex){+.+.}-{3:3}, at: genl_lock net/netlink/genetlink.c:33 [inline] #1: ffffffff8e5b16a8 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg+0x125/0xf50 net/netlink/genetlink.c:848 2 locks held by getty/4007: #0: ffff88814ceda098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc9000325e2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x54a/0x1620 drivers/tty/n_tty.c:2198 3 locks held by kworker/0:4/4295: #0: ffff88814cb7f138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #1: ffffc90003f67d20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #2: ffffffff8e5507a8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xcc/0x16e0 net/ipv6/addrconf.c:4134 4 locks held by kworker/1:6/4301: 4 locks held by kworker/u4:9/4352: #0: ffff88801b292138 ( (wq_completion)writeback ){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #1: ffffc9000456fd20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #2: ffff888073eee650 (sb_internal#3){.+.+}-{0:0}, at: xfs_bmapi_convert_delalloc+0x263/0x12f0 fs/xfs/libxfs/xfs_bmap.c:4512 #3: ffff8880558caf98 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_bmapi_convert_delalloc+0x291/0x12f0 fs/xfs/libxfs/xfs_bmap.c:4517 2 locks held by kworker/u4:10/4361: 2 locks held by syz.4.324/5529: #0: ffff888073eee0e0 (&type->s_umount_key#101){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:362 #1: ffff8881433f07d0 ( &bdi->wb_switch_rwsem ){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline] ){+.+.}-{3:3}, at: sync_inodes_sb+0x270/0xb10 fs/fs-writeback.c:2737 3 locks held by kworker/1:13/6926: #0: ffff888017c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #1: ffffc90003ae7d20 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #2: ffffffff8e5507a8 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:104 3 locks held by kworker/u4:21/6945: #0: ffff888017c79138 ((wq_completion)events_unbound){+.+.}-{0:0} , at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #1: ffffc90003b77d20 ( (linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #2: ffffffff8e5507a8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263 3 locks held by kworker/1:18/8244: #0: ffff88814cb7f138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #1: ffffc90003847d20 ( (work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #2: ffffffff8e5507a8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xcc/0x16e0 net/ipv6/addrconf.c:4134 1 lock held by syz-executor/8762: #0: ffffffff8e5507a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8e5507a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7cb/0x1000 net/core/rtnetlink.c:6147 3 locks held by syz-executor/8763: #0: ffffffff8e5b17f0 (cb_lock){++++}-{3:3}, at: genl_rcv+0x15/0x40 net/netlink/genetlink.c:860 #1: ffffffff8e5b16a8 (genl_mutex){+.+.}-{3:3}, at: genl_lock net/netlink/genetlink.c:33 [inline] #1: ffffffff8e5b16a8 (genl_mutex){+.+.}-{3:3}, at: genl_rcv_msg+0x125/0xf50 net/netlink/genetlink.c:848 #2: ffffffff8e5507a8 (rtnl_mutex){+.+.}-{3:3} , at: ieee80211_register_hw+0x31ed/0x3f10 net/mac80211/main.c:1394 1 lock held by syz-executor/8919: #0: ffffffff8e5507a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8e5507a8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7cb/0x1000 net/core/rtnetlink.c:6147 7 locks held by syz-executor/9077: #0: ffff88807f12c460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x269/0xbc0 fs/read_write.c:580 #1: ffff8880594fdc88 ( &of->mutex ){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e7/0x4f0 fs/kernfs/file.c:325 #2: ffff88802785f0f0 (kn->active#51){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x20b/0x4f0 fs/kernfs/file.c:326 #3: ffffffff8de61a68 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: new_device_store+0x1ad/0x800 drivers/net/netdevsim/bus.c:160 #4: ffff88807d67d0e8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline] #4: ffff88807d67d0e8 (&dev->mutex){....}-{3:3}, at: __device_attach+0x8a/0x570 drivers/base/dd.c:990 #5: ffff88807d67e2f8 (&devlink->lock_key#32){+.+.}-{3:3}, at: nsim_drv_probe+0xc9/0xb20 drivers/net/netdevsim/dev.c:1542 #6: ffffffff8e5507a8 ( rtnl_mutex ){+.+.}-{3:3} , at: register_netdevice_notifier_net+0x16/0xa0 net/core/dev.c:1900 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.1.132-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 nmi_cpu_backtrace+0x4e1/0x560 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1ca/0x430 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline] watchdog+0xf88/0xfd0 kernel/hung_task.c:377 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 3612 Comm: klogd Not tainted 6.1.132-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 RIP: 0010:trace_lock_release include/trace/events/lock.h:69 [inline] RIP: 0010:lock_release+0xd1/0xa20 kernel/locking/lockdep.c:5673 Code: 86 c2 05 00 00 89 db 48 89 d8 48 c1 e8 06 48 8d 3c c5 28 b6 a0 8e be 08 00 00 00 e8 69 31 77 00 48 0f a3 1d 69 da 35 0d 73 0d 5a bb 08 00 84 c0 0f 84 c5 05 00 00 48 c7 c0 f4 ea a0 8e 48 c1 RSP: 0018:ffffc900032d7680 EFLAGS: 00000257 RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffffff816adbb7 RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff8ea0b628 RBP: ffffc900032d77b8 R08: dffffc0000000000 R09: fffffbfff1d416c6 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff9200065aedc R13: ffffffff81d5e40e R14: ffffc900032d7828 R15: dffffc0000000000 FS: 00007f27428aa380(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f41bc179178 CR3: 000000007dbec000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: might_alloc include/linux/sched/mm.h:271 [inline] slab_pre_alloc_hook+0x2a/0x300 mm/slab.h:710 slab_alloc_node mm/slub.c:3318 [inline] kmem_cache_alloc_node+0x52/0x310 mm/slub.c:3443 __alloc_skb+0xd3/0x2c0 net/core/skbuff.c:505 alloc_skb include/linux/skbuff.h:1271 [inline] alloc_skb_with_frags+0xa4/0x740 net/core/skbuff.c:6162 sock_alloc_send_pskb+0x915/0xa50 net/core/sock.c:2750 unix_dgram_sendmsg+0x5b1/0x2060 net/unix/af_unix.c:1918 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:730 [inline] __sys_sendto+0x480/0x600 net/socket.c:2153 __do_sys_sendto net/socket.c:2165 [inline] __se_sys_sendto net/socket.c:2161 [inline] __x64_sys_sendto+0xda/0xf0 net/socket.c:2161 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f2742a0c9b5 Code: 8b 44 24 08 48 83 c4 28 48 98 c3 48 98 c3 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 26 45 31 c9 45 31 c0 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 76 7a 48 8b 15 44 c4 0c 00 f7 d8 64 89 02 48 83 RSP: 002b:00007fff59a07598 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f2742a0c9b5 RDX: 000000000000005d RSI: 000055a10d54d9d0 RDI: 0000000000000003 RBP: 000055a10d546910 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000004000 R11: 0000000000000246 R12: 0000000000000013 R13: 00007f2742b9a212 R14: 00007fff59a07698 R15: 0000000000000000