INFO: task syz-executor:4781 blocked for more than 147 seconds. Not tainted 6.1.114-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:20376 pid:4781 ppid:1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6558 schedule+0xbf/0x180 kernel/sched/core.c:6634 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 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: 0033:0x7fcadd37f327 RSP: 002b:00007fff2b086238 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 00007fcadd3f0134 RCX: 00007fcadd37f327 RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fff2b0862f0 RBP: 00007fff2b0862f0 R08: 0000000000000000 R09: 0000000000000000 R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fff2b087370 R13: 00007fcadd3f0134 R14: 000000000005ded5 R15: 00007fff2b0873b0 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8d32b1d0 (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: ffffffff8d32b9d0 (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/27: #0: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6510 4 locks held by kworker/u4:3/46: 3 locks held by kworker/0:2/919: #0: ffff888017c71938 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #1: ffffc900046e7d20 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #2: ffffffff8e4fafa8 (rtnl_mutex){+.+.}-{3:3}, at: reg_check_chans_work+0x8d/0xdb0 net/wireless/reg.c:2498 1 lock held by dhcpcd/3308: #0: ffffffff8e4fafa8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8e4fafa8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7c1/0xff0 net/core/rtnetlink.c:6147 2 locks held by getty/3391: #0: ffff88802e2c2098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc900031262f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a7/0x1db0 drivers/tty/n_tty.c:2198 3 locks held by kworker/1:3/3651: #0: ffff888017c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #1: ffffc90003f8fd20 ( deferred_process_work ){+.+.}-{0:0} , at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #2: ffffffff8e4fafa8 ( rtnl_mutex ){+.+.}-{3:3} , at: switchdev_deferred_process_work+0xa/0x20 net/switchdev/switchdev.c:104 3 locks held by kworker/0:3/3688: #0: ffff88814b1d5938 ( (wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #1: ffffc900044bfd20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #2: ffffffff8e4fafa8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xcc/0x16b0 net/ipv6/addrconf.c:4115 5 locks held by kworker/u4:9/3781: 4 locks held by kworker/u4:11/3806: 3 locks held by kworker/1:10/3824: #0: ffff88814b1d5938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #1: ffffc90004d07d20 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #2: ffffffff8e4fafa8 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xcc/0x16b0 net/ipv6/addrconf.c:4115 7 locks held by kworker/u4:15/4539: 2 locks held by syz-executor/4781: #0: ffff8880618900e0 (&type->s_umount_key#48){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:362 #1: ffff8881443627d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline] #1: ffff8881443627d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x270/0xb10 fs/fs-writeback.c:2737 2 locks held by syz-executor/5248: #0: ffff8880290540e0 (&type->s_umount_key#48){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:362 #1: ffff888024f2c7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline] #1: ffff888024f2c7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x270/0xb10 fs/fs-writeback.c:2737 2 locks held by syz-executor/6417: #0: ffff88805ba8c0e0 ( &type->s_umount_key #48 ){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:362 #1: ffff888024dfc7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline] #1: ffff888024dfc7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x270/0xb10 fs/fs-writeback.c:2737 2 locks held by syz-executor/6479: #0: ffff888063f1a0e0 (&type->s_umount_key#48){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:362 #1: ffff8881443707d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline] #1: ffff8881443707d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x270/0xb10 fs/fs-writeback.c:2737 2 locks held by syz-executor/6601: #0: ffff88805bdae0e0 (&type->s_umount_key#48){++++}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:362 #1: ffff8881443767d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline] #1: ffff8881443767d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x270/0xb10 fs/fs-writeback.c:2737 4 locks held by kworker/u4:17/6994: 4 locks held by kworker/u4:18/6996: 4 locks held by kworker/u4:25/7012: #0: ffff888017e16938 ( (wq_completion)netns ){+.+.}-{0:0} , at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #1: ffffc90003c3fd20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #2: ffffffff8e4eec50 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xf1/0xb60 net/core/net_namespace.c:566 #3: ffffffff8e4fafa8 (rtnl_mutex){+.+.}-{3:3}, at: netdev_wait_allrefs_any net/core/dev.c:10287 [inline] #3: ffffffff8e4fafa8 (rtnl_mutex){+.+.}-{3:3}, at: netdev_run_todo+0x8c7/0xf40 net/core/dev.c:10398 2 locks held by kworker/u4:27/7018: 1 lock held by syz-executor/7511: #0: ffffffff8e4fafa8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8e4fafa8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7c1/0xff0 net/core/rtnetlink.c:6147 8 locks held by syz-executor/7547: #0: ffff88807ec2e460 (sb_writers #8 ){.+.+}-{0:0} , at: vfs_write+0x269/0xbc0 fs/read_write.c:580 #1: ffff88802a3b7488 ( &of->mutex ){+.+.}-{3:3} , at: kernfs_fop_write_iter+0x1e7/0x4f0 fs/kernfs/file.c:325 #2: ffff888145399830 (kn->active#50){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x20b/0x4f0 fs/kernfs/file.c:326 #3: ffffffff8de24168 (nsim_bus_dev_list_lock ){+.+.}-{3:3} , at: del_device_store+0xf8/0x480 drivers/net/netdevsim/bus.c:209 #4: ffff88802d7620e8 ( &dev->mutex ){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline] ){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1080 [inline] ){....}-{3:3}, at: device_release_driver_internal+0xb6/0x880 drivers/base/dd.c:1283 #5: ffff88802d7632f8 ( &devlink->lock_key #20 ){+.+.}-{3:3} , at: nsim_drv_remove+0x54/0x160 drivers/net/netdevsim/dev.c:1674 #6: ffffffff8e4fafa8 (rtnl_mutex){+.+.}-{3:3}, at: nsim_destroy+0x3a/0x140 drivers/net/netdevsim/netdev.c:381 #7: ffffffff8d3305f8 (rcu_state.exp_mutex){+.+.}-{3:3} , at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline] , at: synchronize_rcu_expedited+0x4f0/0x930 kernel/rcu/tree_exp.h:962 3 locks held by kworker/u4:30/7559: #0: ffff888017c79138 ( (wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #1: ffffc900165e7d20 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #2: ffffffff8e4fafa8 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xa/0x50 net/core/link_watch.c:263 4 locks held by syz-executor/7562: #0: ffff88807ec2e460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x269/0xbc0 fs/read_write.c:580 #1: ffff8880785e1088 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e7/0x4f0 fs/kernfs/file.c:325 #2: ffff888145399830 (kn->active#50){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x20b/0x4f0 fs/kernfs/file.c:326 #3: ffffffff8de24168 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xf8/0x480 drivers/net/netdevsim/bus.c:209 1 lock held by syz-executor/7564: #0: ffffffff8e4fafa8 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:74 [inline] #0: ffffffff8e4fafa8 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x7c1/0xff0 net/core/rtnetlink.c:6147 2 locks held by syz-executor/7637: #0: ffffffff8e4eec50 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x378/0x5d0 net/core/net_namespace.c:477 #1: ffffffff8e4fafa8 (rtnl_mutex){+.+.}-{3:3}, at: wg_netns_pre_exit+0x1b/0x1d0 drivers/net/wireguard/device.c:420 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: khungtaskd Not tainted 6.1.114-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 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+0x1ae/0x3f0 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: 6996 Comm: kworker/u4:18 Not tainted 6.1.114-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 Workqueue: writeback wb_workfn (flush-7:3) RIP: 0010:io_serial_in+0x72/0xb0 drivers/tty/serial/8250/8250_port.c:461 Code: 24 63 d7 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 b5 e4 2e 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:ffffc9000397dd38 EFLAGS: 00000002 RAX: 1ffffffff2ed7b00 RBX: ffffffff976bdec0 RCX: 0000000000000000 RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020 RBP: 0000000000000000 R08: ffffffff84b33032 R09: ffffed1004926047 R10: 0000000000000000 R11: dffffc0000000001 R12: ffffffff97379e30 R13: 00000000000026ec R14: 00000000000003fd R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055bd1453ce08 CR3: 000000002e603000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: serial_in drivers/tty/serial/8250/8250.h:117 [inline] serial_lsr_in drivers/tty/serial/8250/8250.h:139 [inline] wait_for_lsr drivers/tty/serial/8250/8250_port.c:2100 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3367 [inline] serial8250_console_write+0x1057/0x1750 drivers/tty/serial/8250/8250_port.c:3445 call_console_driver kernel/printk/printk.c:1977 [inline] console_emit_next_record+0xbb4/0x1000 kernel/printk/printk.c:2777 console_unlock+0x278/0x7c0 kernel/printk/printk.c:2906 vprintk_emit+0x523/0x740 kernel/printk/printk.c:2303 _printk+0xd1/0x111 kernel/printk/printk.c:2328 _udf_err+0x137/0x180 fs/udf/super.c:2353 udf_bitmap_new_block fs/udf/balloc.c:357 [inline] udf_new_block+0x1bb4/0x2130 fs/udf/balloc.c:730 inode_getblk fs/udf/inode.c:769 [inline] udf_get_block+0x1a69/0x5360 fs/udf/inode.c:359 __block_write_full_page+0x33a/0x1680 fs/buffer.c:1745 __mpage_writepage+0x1495/0x1930 fs/mpage.c:629 write_cache_pages+0x92e/0x15c0 mm/page-writeback.c:2382 mpage_writepages+0x103/0x1d0 fs/mpage.c:664 do_writepages+0x3a2/0x670 mm/page-writeback.c:2491 __writeback_single_inode+0x15d/0x11e0 fs/fs-writeback.c:1612 writeback_sb_inodes+0xc2b/0x1b20 fs/fs-writeback.c:1903 wb_writeback+0x49d/0xe10 fs/fs-writeback.c:2077 wb_do_writeback fs/fs-writeback.c:2220 [inline] wb_workfn+0x427/0x1020 fs/fs-writeback.c:2260 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295