INFO: task kworker/u8:3:57 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:3 state:D stack:21536 pid:57 tgid:57 ppid:2 task_flags:0x4208160 flags:0x00080000 Workqueue: writeback wb_workfn (flush-btrfs-23) Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6908 __schedule_loop kernel/sched/core.c:6990 [inline] schedule+0x164/0x360 kernel/sched/core.c:7005 wait_extent_bit fs/btrfs/extent-io-tree.c:811 [inline] btrfs_lock_extent_bits+0x59c/0x700 fs/btrfs/extent-io-tree.c:1914 btrfs_lock_extent fs/btrfs/extent-io-tree.h:152 [inline] btrfs_invalidate_folio+0x43d/0xc40 fs/btrfs/inode.c:7685 extent_writepage fs/btrfs/extent_io.c:1852 [inline] extent_write_cache_pages fs/btrfs/extent_io.c:2580 [inline] btrfs_writepages+0x12ff/0x2440 fs/btrfs/extent_io.c:2713 do_writepages+0x32e/0x550 mm/page-writeback.c:2554 __writeback_single_inode+0x133/0x11a0 fs/fs-writeback.c:1750 writeback_sb_inodes+0x995/0x19d0 fs/fs-writeback.c:2042 wb_writeback+0x456/0xb70 fs/fs-writeback.c:2227 wb_do_writeback fs/fs-writeback.c:2374 [inline] wb_workfn+0x41a/0xf60 fs/fs-writeback.c:2414 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 INFO: task syz.3.222:7760 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.222 state:D stack:22752 pid:7760 tgid:7759 ppid:7243 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6908 __schedule_loop kernel/sched/core.c:6990 [inline] schedule+0x164/0x360 kernel/sched/core.c:7005 wait_current_trans+0x39f/0x590 fs/btrfs/transaction.c:535 start_transaction+0x6a7/0x1650 fs/btrfs/transaction.c:705 clone_copy_inline_extent fs/btrfs/reflink.c:299 [inline] btrfs_clone+0x128a/0x24d0 fs/btrfs/reflink.c:529 btrfs_clone_files+0x271/0x3f0 fs/btrfs/reflink.c:750 btrfs_remap_file_range+0x76b/0x1320 fs/btrfs/reflink.c:903 vfs_copy_file_range+0xda7/0x1390 fs/read_write.c:1600 __do_sys_copy_file_range fs/read_write.c:1683 [inline] __se_sys_copy_file_range+0x2fb/0x480 fs/read_write.c:1650 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fee9e3ac799 RSP: 002b:00007fee9c606028 EFLAGS: 00000246 ORIG_RAX: 0000000000000146 RAX: ffffffffffffffda RBX: 00007fee9e625fa0 RCX: 00007fee9e3ac799 RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000005 RBP: 00007fee9e442c99 R08: 0000000000000863 R09: 0000000000000000 R10: 00002000000000c0 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fee9e626038 R14: 00007fee9e625fa0 R15: 00007ffdc0a74538 INFO: task syz.3.222:7780 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.222 state:D stack:28112 pid:7780 tgid:7759 ppid:7243 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6908 __schedule_loop kernel/sched/core.c:6990 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7286 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 __rwbase_read_lock+0xc3/0x180 kernel/locking/rwbase_rt.c:114 rwbase_read_lock kernel/locking/rwbase_rt.c:147 [inline] __down_read kernel/locking/rwsem.c:1466 [inline] down_read+0x132/0x200 kernel/locking/rwsem.c:1539 btrfs_page_mkwrite+0x60e/0x1b10 fs/btrfs/file.c:1918 do_page_mkwrite+0x150/0x310 mm/memory.c:3589 wp_page_shared mm/memory.c:3990 [inline] do_wp_page+0x203b/0x49d0 mm/memory.c:4209 handle_pte_fault mm/memory.c:6333 [inline] __handle_mm_fault mm/memory.c:6455 [inline] handle_mm_fault+0x9f5/0x13c0 mm/memory.c:6624 do_user_addr_fault+0x75b/0x1340 arch/x86/mm/fault.c:1385 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0010:rep_movs_alternative+0x33/0x90 arch/x86/lib/copy_user_64.S:61 Code: 73 25 85 c9 74 0f 8a 06 88 07 48 ff c7 48 ff c6 48 ff c9 75 f1 c3 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 8b 06 <48> 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 db 83 f9 08 73 e8 eb RSP: 0018:ffffc90004dd7de8 EFLAGS: 00050246 RAX: 0000000000000009 RBX: 0000000000000008 RCX: 0000000000000008 RDX: 0000000000000000 RSI: ffffc90004dd7e40 RDI: 0000200000000080 RBP: ffffc90004dd7ea8 R08: ffffc90004dd7e47 R09: 1ffff920009bafc8 R10: dffffc0000000000 R11: fffff520009bafc9 R12: 0000200000000088 R13: 00007ffffffff000 R14: ffffc90004dd7e40 R15: 0000200000000080 copy_user_generic arch/x86/include/asm/uaccess_64.h:126 [inline] raw_copy_to_user arch/x86/include/asm/uaccess_64.h:147 [inline] _inline_copy_to_user include/linux/uaccess.h:206 [inline] _copy_to_user+0x8a/0xb0 lib/usercopy.c:26 copy_to_user include/linux/uaccess.h:236 [inline] btrfs_ioctl_start_sync+0xe2/0x1b0 fs/btrfs/ioctl.c:2985 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl+0xff/0x170 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fee9e3ac799 RSP: 002b:00007fee9c5e5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fee9e626090 RCX: 00007fee9e3ac799 RDX: 0000200000000080 RSI: 0000000080089418 RDI: 0000000000000005 RBP: 00007fee9e442c99 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fee9e626128 R14: 00007fee9e626090 R15: 00007ffdc0a74538 INFO: task btrfs-transacti:7778 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:btrfs-transacti state:D stack:24160 pid:7778 tgid:7778 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1553/0x5240 kernel/sched/core.c:6908 __schedule_loop kernel/sched/core.c:6990 [inline] schedule+0x164/0x360 kernel/sched/core.c:7005 wb_wait_for_completion+0x3e8/0x790 fs/fs-writeback.c:227 __writeback_inodes_sb_nr+0x24c/0x2d0 fs/fs-writeback.c:2838 try_to_writeback_inodes_sb+0x9a/0xc0 fs/fs-writeback.c:2886 btrfs_start_delalloc_flush fs/btrfs/transaction.c:2159 [inline] btrfs_commit_transaction+0x82e/0x31a0 fs/btrfs/transaction.c:2348 transaction_kthread+0x2b1/0x450 fs/btrfs/disk-io.c:1545 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Showing all locks held in the system: 1 lock held by khungtaskd/37: #0: ffffffff8ddcb880 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8ddcb880 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8ddcb880 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by kworker/u8:3/57: #0: ffff88801ee8b138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline] #0: ffff88801ee8b138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358 #1: ffffc9000123fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #1: ffffc9000123fc40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358 5 locks held by kworker/u8:5/70: 7 locks held by kworker/u8:6/144: 2 locks held by getty/5559: #0: ffff8880376470a0 (&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 3 locks held by udevd/5914: 1 lock held by syz-executor/7408: #0: ffff88805657e0d0 (&type->s_umount_key#71){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff88805657e0d0 (&type->s_umount_key#71){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff88805657e0d0 (&type->s_umount_key#71){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508 2 locks held by syz-executor/7735: #0: ffff8880244780d0 (&type->s_umount_key#32){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff8880244780d0 (&type->s_umount_key#32){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff8880244780d0 (&type->s_umount_key#32){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508 #1: ffff888019c4f238 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_remove+0x30/0x60 fs/kernfs/dir.c:1554 4 locks held by syz.3.222/7760: #0: ffff88805718e480 (sb_writers#14){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline] #0: ffff88805718e480 (sb_writers#14){.+.+}-{0:0}, at: vfs_copy_file_range+0x9bb/0x1390 fs/read_write.c:1588 #1: ffff88806015e318 (&sb->s_type->i_mutex_key#25){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline] #1: ffff88806015e318 (&sb->s_type->i_mutex_key#25){++++}-{4:4}, at: btrfs_inode_lock+0x51/0xe0 fs/btrfs/inode.c:369 #2: ffff88806015e178 (&ei->i_mmap_lock){++++}-{4:4}, at: btrfs_inode_lock+0xcb/0xe0 fs/btrfs/inode.c:372 #3: ffff88805718e770 (sb_internal#4){.+.+}-{0:0}, at: clone_copy_inline_extent fs/btrfs/reflink.c:299 [inline] #3: ffff88805718e770 (sb_internal#4){.+.+}-{0:0}, at: btrfs_clone+0x128a/0x24d0 fs/btrfs/reflink.c:529 3 locks held by syz.3.222/7780: #0: ffff8880280a4370 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_trylock include/linux/mmap_lock.h:611 [inline] #0: ffff8880280a4370 (&mm->mmap_lock){++++}-{4:4}, at: get_mmap_lock_carefully mm/mmap_lock.c:441 [inline] #0: ffff8880280a4370 (&mm->mmap_lock){++++}-{4:4}, at: lock_mm_and_find_vma+0x36/0x340 mm/mmap_lock.c:501 #1: ffff88805718e5f8 (sb_pagefaults#2){.+.+}-{0:0}, at: do_page_mkwrite+0x150/0x310 mm/memory.c:3589 #2: ffff88806015e178 (&ei->i_mmap_lock){++++}-{4:4}, at: btrfs_page_mkwrite+0x60e/0x1b10 fs/btrfs/file.c:1918 4 locks held by btrfs-transacti/7778: #0: ffff888043f48d98 (&fs_info->transaction_kthread_mutex){+.+.}-{4:4}, at: transaction_kthread+0xe4/0x450 fs/btrfs/disk-io.c:1515 #1: ffff888043f4b118 (btrfs_trans_num_writers){++++}-{0:0}, at: join_transaction+0x41b/0xc90 fs/btrfs/transaction.c:298 #2: ffff888043f4b140 (btrfs_trans_num_extwriters){++++}-{0:0}, at: join_transaction+0x41b/0xc90 fs/btrfs/transaction.c:298 #3: ffff88805718e0d0 (&type->s_umount_key#60){++++}-{4:4}, at: try_to_writeback_inodes_sb+0x22/0xc0 fs/fs-writeback.c:2883 7 locks held by syz-executor/8566: 2 locks held by syz.7.426/9775: #0: ffff88805718e0d0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline] #0: ffff88805718e0d0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122 #1: ffff8880323d88c0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:398 [inline] #1: ffff8880323d88c0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x1c5/0xc10 fs/fs-writeback.c:2922 2 locks held by syz.7.426/9811: #0: ffff88805718e0d0 (&type->s_umount_key#60){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline] #0: ffff88805718e0d0 (&type->s_umount_key#60){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122 #1: ffff8880323d88c0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:398 [inline] #1: ffff8880323d88c0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x1c5/0xc10 fs/fs-writeback.c:2922 4 locks held by syz.8.482/10347: 1 lock held by syz-executor/10369: #0: ffffffff8f15a0f8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8f15a0f8 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x404/0x1ad0 net/ipv4/devinet.c:978 2 locks held by dhcpcd-run-hook/10380: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 37 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/27/2026 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+0xfd9/0x1030 kernel/hung_task.c:515 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 144 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/27/2026 Workqueue: netns cleanup_net RIP: 0010:__bfs kernel/locking/lockdep.c:1815 [inline] RIP: 0010:__bfs_backwards kernel/locking/lockdep.c:1860 [inline] RIP: 0010:check_irq_usage kernel/locking/lockdep.c:2796 [inline] RIP: 0010:check_prev_add kernel/locking/lockdep.c:3169 [inline] RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3284 [inline] RIP: 0010:validate_chain kernel/locking/lockdep.c:3908 [inline] RIP: 0010:__lock_acquire+0x197b/0x2cf0 kernel/locking/lockdep.c:5237 Code: 13 25 ff 0f 00 00 39 05 8f a8 b5 11 73 06 89 05 87 a8 b5 11 48 8b 02 48 89 df 4c 39 e8 0f 84 2c fe ff ff 4c 89 60 30 48 8b 00 <4c> 39 e8 75 f4 48 89 df e9 18 fe ff ff 48 89 fb 48 c7 c7 10 8b c9 RSP: 0018:ffffc90003b46f70 EFLAGS: 00000006 RAX: ffffffff95f7f088 RBX: 0000000000000145 RCX: 0000000000000004 RDX: ffffffff95d98738 RSI: ffff88801ffeab50 RDI: 0000000000000145 RBP: 6e9a6e8e8dafe229 R08: ffffc90003b46f38 R09: 0000000000000020 R10: dffffc0000000000 R11: ffffffff81a08120 R12: ffffffff95d987a8 R13: ffffffff92f72a10 R14: ffff88801ffe9e80 R15: 0000000000000003 FS: 0000000000000000(0000) GS:ffff88812633f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110f27099f CR3: 0000000039c9e000 CR4: 00000000003526f0 Call Trace: lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868 __raw_spin_lock include/linux/spinlock_api_smp.h:158 [inline] _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154 class_raw_spinlock_constructor include/linux/spinlock.h:534 [inline] pcpu_alloc+0x1d2/0x360 lib/debugobjects.c:281 alloc_object+0xbf/0x300 lib/debugobjects.c:475 lookup_object_or_alloc lib/debugobjects.c:702 [inline] debug_object_activate+0x153/0x520 lib/debugobjects.c:837 debug_rcu_head_queue kernel/rcu/rcu.h:236 [inline] __call_rcu_common kernel/rcu/tree.c:3116 [inline] call_rcu+0x43/0x890 kernel/rcu/tree.c:3251 kernfs_put+0x191/0x470 fs/kernfs/dir.c:591 sysfs_put include/linux/sysfs.h:808 [inline] __kobject_del+0xe9/0x330 lib/kobject.c:605 kobject_del lib/kobject.c:627 [inline] kset_unregister+0x56/0x80 lib/kobject.c:890 remove_queue_kobjects net/core/net-sysfs.c:2177 [inline] netdev_unregister_kobject+0x33a/0x450 net/core/net-sysfs.c:2325 unregister_netdevice_many_notify+0x1dfa/0x2360 net/core/dev.c:12449 unregister_netdevice_many net/core/dev.c:12477 [inline] unregister_netdevice_queue+0x31f/0x360 net/core/dev.c:12291 unregister_netdevice include/linux/netdevice.h:3408 [inline] nsim_destroy+0x1e5/0x680 drivers/net/netdevsim/netdev.c:1182 __nsim_dev_port_del+0x14d/0x1b0 drivers/net/netdevsim/dev.c:1528 nsim_dev_port_del_all drivers/net/netdevsim/dev.c:1540 [inline] nsim_dev_reload_destroy+0x288/0x490 drivers/net/netdevsim/dev.c:1764 nsim_dev_reload_down+0x8a/0xc0 drivers/net/netdevsim/dev.c:1038 devlink_reload+0x1d1/0x8e0 net/devlink/dev.c:461 devlink_pernet_pre_exit+0x1e6/0x3f0 net/devlink/core.c:507 ops_pre_exit_list net/core/net_namespace.c:161 [inline] ops_undo_list+0x187/0x940 net/core/net_namespace.c:234 cleanup_net+0x56e/0x800 net/core/net_namespace.c:704 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245