INFO: task syz-executor:4270 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:22064 pid:4270 ppid:1 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5245 [inline] __schedule+0x11d1/0x40e0 kernel/sched/core.c:6562 schedule+0xb9/0x180 kernel/sched/core.c:6638 wb_wait_for_completion+0x16f/0x290 fs/fs-writeback.c:191 sync_inodes_sb+0x1c5/0xa10 fs/fs-writeback.c:2756 sync_filesystem+0x16d/0x220 fs/sync.c:64 generic_shutdown_super+0x6b/0x340 fs/super.c:474 kill_block_super+0x7c/0xe0 fs/super.c:1470 deactivate_locked_super+0x93/0xf0 fs/super.c:332 cleanup_mnt+0x42c/0x4b0 fs/namespace.c:1191 task_work_run+0x1d0/0x260 kernel/task_work.c:203 exit_task_work include/linux/task_work.h:39 [inline] do_exit+0x982/0x2480 kernel/exit.c:880 do_group_exit+0x217/0x2d0 kernel/exit.c:1022 __do_sys_exit_group kernel/exit.c:1033 [inline] __se_sys_exit_group kernel/exit.c:1031 [inline] __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f2cac59c799 RSP: 002b:00007ffcce4efdb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007f2cac632002 RCX: 00007f2cac59c799 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000010 R08: 0000000000000000 R09: 00007f2cac631f90 R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffcce4f1070 R13: 00007f2cac631f90 R14: 000055558ca254e8 R15: 00007ffcce4f2140 Showing all locks held in the system: 5 locks held by kworker/u4:0/9: #0: ffff888017616938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #1: ffffc900000e7d00 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #2: ffffffff8dd39b10 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x148/0xba0 net/core/net_namespace.c:594 #3: ffff88802fce93e8 (&wg->device_update_lock){+.+.}-{3:3}, at: wg_destruct+0x112/0x300 drivers/net/wireguard/device.c:249 #4: ffffffff8cb331c0 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x48/0x600 kernel/rcu/tree.c:4023 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8cb2dfb0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffffffff8cb2e7d0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xf00 kernel/rcu/tasks.h:517 1 lock held by khungtaskd/27: #0: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8cb2d620 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6513 2 locks held by getty/4029: #0: ffff88802fa53098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x429/0x1390 drivers/tty/n_tty.c:2198 2 locks held by syz-executor/4270: #0: ffff88801d6440e0 (&type->s_umount_key#97){++++}-{3:3}, at: deactivate_super+0xa0/0xd0 fs/super.c:362 #1: ffff88802480c7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline] #1: ffff88802480c7d0 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x1a9/0xa10 fs/fs-writeback.c:2754 3 locks held by kworker/u4:6/4323: 2 locks held by kworker/u4:8/4418: #0: ffff88801c643938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #1: ffffc9000451fd00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 1 lock held by udevd/4529: 1 lock held by udevd/4628: #0: ffff88801787be20 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock_shared include/linux/fs.h:768 [inline] #0: ffff88801787be20 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: blkdev_read_iter+0x41d/0x570 block/fops.c:667 6 locks held by kworker/u4:19/6852: #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #1: ffffc9000d3bfd00 ((work_completion)(&rdev->wiphy_work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #2: ffff888023cc07c8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: wiphy_lock include/net/cfg80211.h:5693 [inline] #2: ffff888023cc07c8 (&rdev->wiphy.mtx){+.+.}-{3:3}, at: cfg80211_wiphy_work+0x31/0x260 net/wireless/core.c:420 #3: ffff88802a758d40 (&wdev->mtx){+.+.}-{3:3}, at: sdata_lock net/mac80211/ieee80211_i.h:1114 [inline] #3: ffff88802a758d40 (&wdev->mtx){+.+.}-{3:3}, at: ieee80211_ibss_work+0xa8/0x10f0 net/mac80211/ibss.c:1680 #4: ffff888023cc1780 (&local->sta_mtx){+.+.}-{3:3}, at: ieee80211_ibss_sta_expire net/mac80211/ibss.c:1256 [inline] #4: ffff888023cc1780 (&local->sta_mtx){+.+.}-{3:3}, at: ieee80211_sta_merge_ibss net/mac80211/ibss.c:1299 [inline] #4: ffff888023cc1780 (&local->sta_mtx){+.+.}-{3:3}, at: ieee80211_ibss_work+0x57f/0x10f0 net/mac80211/ibss.c:1708 #5: ffffffff8cb332f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline] #5: ffffffff8cb332f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962 2 locks held by segctord/10319: 2 locks held by kworker/0:2/14574: #0: ffff888017472138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 #1: ffffc900035d7d00 ((work_completion)(&rew->rew_work)){+.+.}-{0:0}, at: process_one_work+0x7b0/0x1160 kernel/workqueue.c:2267 4 locks held by syz-executor/15290: #0: ffff88807e55c460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x26b/0xa30 fs/read_write.c:580 #1: ffff8880585f1488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e3/0x520 fs/kernfs/file.c:343 #2: ffff8881453ac918 (kn->active#53){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff8881453ac918 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x236/0x520 fs/kernfs/file.c:344 #3: ffffffff8d655de8 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd4/0x360 drivers/net/netdevsim/bus.c:209 6 locks held by syz-executor/15313: #0: ffff88807e55c460 (sb_writers#8){.+.+}-{0:0}, at: vfs_write+0x26b/0xa30 fs/read_write.c:580 #1: ffff88802fdbb488 (&of->mutex){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x1e3/0x520 fs/kernfs/file.c:343 #2: ffff8881453ac918 (kn->active#53){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff8881453ac918 (kn->active#53){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x236/0x520 fs/kernfs/file.c:344 #3: ffffffff8d655de8 (nsim_bus_dev_list_lock){+.+.}-{3:3}, at: del_device_store+0xd4/0x360 drivers/net/netdevsim/bus.c:209 #4: ffff88807f2fe0e8 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:840 [inline] #4: ffff88807f2fe0e8 (&dev->mutex){....}-{3:3}, at: __device_driver_lock drivers/base/dd.c:1080 [inline] #4: ffff88807f2fe0e8 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0xb2/0x850 drivers/base/dd.c:1283 #5: ffff88807f2ff2f8 (&devlink->lock_key#4){+.+.}-{3:3}, at: nsim_drv_remove+0x54/0x170 drivers/net/netdevsim/dev.c:1678 1 lock held by udevadm/15509: 2 locks held by cmp/15511: ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 27 Comm: khungtaskd Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1d4/0x450 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+0xeee/0xf30 kernel/hung_task.c:377 kthread+0x29d/0x330 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: 4254 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:check_preemption_disabled+0x6/0x110 lib/smp_processor_id.c:13 Code: 89 f6 e8 6d bc 0b fa e9 6e ff ff ff 00 00 cc cc 00 00 cc cc 48 c7 c7 00 0f df 8a 48 c7 c6 40 0f df 8a eb 00 55 41 57 41 56 53 <48> 83 ec 10 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 65 8b 05 51 RSP: 0018:ffffc90003b57a10 EFLAGS: 00000046 RAX: 0000000000000000 RBX: ffff88807a65d940 RCX: d2ee112003fe9100 RDX: 0000000000000010 RSI: ffffffff8a8c23a0 RDI: ffffffff8adf0f60 RBP: 0000000000000000 R08: ffffc90003b57baf R09: ffffc90003b57ba0 R10: dffffc0000000000 R11: fffff5200076af76 R12: ffff88807a65d940 R13: 0000000000000246 R14: ffffffff8cb2d6e0 R15: 00000000ffffffff FS: 0000555583fd2500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6265591440 CR3: 0000000026b52000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: lockdep_recursion_finish kernel/locking/lockdep.c:467 [inline] lock_is_held_type+0x100/0x190 kernel/locking/lockdep.c:5706 lock_is_held include/linux/lockdep.h:283 [inline] schedule_debug kernel/sched/core.c:5823 [inline] __schedule+0x20e/0x40e0 kernel/sched/core.c:6455 schedule+0xb9/0x180 kernel/sched/core.c:6638 do_nanosleep+0x1a9/0x600 kernel/time/hrtimer.c:2088 hrtimer_nanosleep+0x171/0x370 kernel/time/hrtimer.c:2136 __do_sys_clock_nanosleep kernel/time/posix-timers.c:1314 [inline] __se_sys_clock_nanosleep+0x30b/0x3a0 kernel/time/posix-timers.c:1291 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fc495b57917 Code: 48 89 fa 4c 89 df e8 a8 56 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:00007fff18b021f0 EFLAGS: 00000202 ORIG_RAX: 00000000000000e6 RAX: ffffffffffffffda RBX: 0000555583fd2500 RCX: 00007fc495b57917 RDX: 00007fff18b02230 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007fff18b02710 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000004 R13: 00007fff18b0226c R14: 00007fff18b02300 R15: 0000000000000000