INFO: task syz-executor:4246 blocked for more than 143 seconds. Not tainted 6.1.129-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:20416 pid:4246 ppid:1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5243 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6560 schedule+0xbf/0x180 kernel/sched/core.c:6636 rwsem_down_write_slowpath+0xea1/0x14b0 kernel/locking/rwsem.c:1189 deactivate_super+0xa9/0xe0 fs/super.c:362 cleanup_mnt+0x490/0x520 fs/namespace.c:1186 task_work_run+0x246/0x300 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177 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: 0033:0x7f17e6d8e497 RSP: 002b:00007fff9bf1a7e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007f17e6e0e08c RCX: 00007f17e6d8e497 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff9bf1a8a0 RBP: 00007fff9bf1a8a0 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fff9bf1b930 R13: 00007f17e6e0e08c R14: 000000000005f7c6 R15: 00007fff9bf1b970 INFO: task syz.4.1021:9971 blocked for more than 143 seconds. Not tainted 6.1.129-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.1021 state:D stack:28416 pid:9971 ppid:4247 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5243 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6560 schedule+0xbf/0x180 kernel/sched/core.c:6636 wb_wait_for_completion+0x162/0x290 fs/fs-writeback.c:191 sync_inodes_sb+0x28f/0xb10 fs/fs-writeback.c:2739 iterate_supers+0x127/0x1e0 fs/super.c:757 ksys_sync+0xb9/0x1c0 fs/sync.c:102 __do_sys_sync+0xa/0x10 fs/sync.c:113 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: 0033:0x7f6997f8d169 RSP: 002b:00007f6997dff038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f69981a6080 RCX: 00007f6997f8d169 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f69981a6080 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000001 R14: 00007f69981a6080 R15: 00007ffe906d3488 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8d32e850 (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: ffffffff8d32f050 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3} , at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517 5 locks held by kworker/1:1/26: 1 lock held by khungtaskd/28: #0: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8d32e680 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6510 2 locks held by kworker/1:2/128: #0: ffff888017c72138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #1: ffffc90002dc7d20 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 1 lock held by dhcpcd/3915: #0: ffffffff8e54faa8 (rtnl_mutex){+.+.}-{3:3}, at: __netlink_dump_start+0x136/0x6d0 net/netlink/af_netlink.c:2287 2 locks held by getty/4001: #0: ffff8880313cb098 ( &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 1 lock held by syz-executor/4246: #0: ffff888019ec60e0 (&type->s_umount_key#80){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:362 4 locks held by kworker/u4:9/4532: #0: ffff888017e16938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #1: ffffc900049dfd20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #2: ffffffff8e542f90 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x166/0xd20 net/core/net_namespace.c:594 #3: ffffffff8e54faa8 (rtnl_mutex){+.+.}-{3:3}, at: wiphy_unregister+0x22f/0xb10 net/wireless/core.c:1091 4 locks held by kworker/u4:13/4550: #0: ffff88801c657938 ( (wq_completion)writeback ){+.+.}-{0:0} , at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #1: ffffc90004a5fd20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #2: ffff888019ec6650 (sb_internal#3){.+.+}-{0:0}, at: xfs_bmapi_convert_delalloc+0x263/0x12f0 fs/xfs/libxfs/xfs_bmap.c:4507 #3: ffff8880747c08d8 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_bmapi_convert_delalloc+0x291/0x12f0 fs/xfs/libxfs/xfs_bmap.c:4512 3 locks held by kworker/u4:14/4683: #0: ffff888017c79138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #1: ffffc900050d7d20 ( (linkwatch_work).work ){+.+.}-{0:0} , at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #2: ffffffff8e54faa8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263 3 locks held by kworker/0:10/5104: #0: ffff8880306d7d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #1: ffffc9000d9cfd20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #2: ffffffff8e54faa8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xcc/0x16e0 net/ipv6/addrconf.c:4134 2 locks held by kworker/0:14/5108: 3 locks held by kworker/1:19/7398: #0: ffff8880306d7d38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #1: ffffc90003767d20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x806/0x1260 kernel/workqueue.c:2267 #2: ffffffff8e54faa8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xcc/0x16e0 net/ipv6/addrconf.c:4134 2 locks held by syz.4.1021/9971: #0: ffff888019ec60e0 (&type->s_umount_key#80){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:755 #1: ffff888142f147d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline] #1: ffff888142f147d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x270/0xb10 fs/fs-writeback.c:2737 1 lock held by syz.9.1086/10332: #0: ffff888019ec60e0 (&type->s_umount_key#80){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:755 1 lock held by syz.3.1215/11272: #0: ffff888019ec60e0 (&type->s_umount_key#80){++++}-{3:3}, at: iterate_supers+0xac/0x1e0 fs/super.c:755 1 lock held by syz-executor/11550: #0: ffffffff8e54faa8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8e54faa8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7cb/0x1000 net/core/rtnetlink.c:6147 1 lock held by syz-executor/11608: #0: ffffffff8e54faa8 (rtnl_mutex ){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] ){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7cb/0x1000 net/core/rtnetlink.c:6147 2 locks held by syz-executor/11780: #0: ffffffff8e54faa8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8e54faa8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7cb/0x1000 net/core/rtnetlink.c:6147 #1: ffffffff8d333cb8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline] #1: ffffffff8d333cb8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x360/0x930 kernel/rcu/tree_exp.h:962 1 lock held by syz.5.1323/12181: #0: ffffffff8e54faa8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8e54faa8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7cb/0x1000 net/core/rtnetlink.c:6147 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.1.129-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 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5108 Comm: kworker/0:14 Not tainted 6.1.129-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: xfs-buf/loop0 xfs_buf_ioend_work RIP: 0010:io_serial_in+0x72/0xb0 drivers/tty/serial/8250/8250_port.c:461 Code: 74 a2 cd fc 89 e9 41 d3 e6 48 83 c3 40 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 95 fa 24 fd 44 03 33 44 89 f2 ec <0f> b6 c0 5b 41 5e 41 5f 5d c3 89 e9 80 e1 07 38 c1 7c ad 48 89 ef RSP: 0018:ffffc9000da6f238 EFLAGS: 00000002 RAX: 1ffffffff2ee8900 RBX: ffffffff97744800 RCX: 0000000000000000 RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020 RBP: 0000000000000000 R08: ffffffff84bcf452 R09: ffffed1004a3a047 R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000 R13: ffffffff977447c0 R14: 00000000000003fd R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b3031fffc CR3: 000000007e5f6000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295