INFO: task kworker/u4:0:9 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:0    state:D stack:25104 pid:    9 ppid:     2 flags:0x00004000
Workqueue: btrfs-endio-write btrfs_work_helper
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 wait_on_state fs/btrfs/extent_io.c:868 [inline]
 wait_extent_bit+0x3ad/0x4e0 fs/btrfs/extent_io.c:906
 lock_extent_bits+0x85/0x110 fs/btrfs/extent_io.c:1469
 btrfs_finish_ordered_io+0x6ab/0x1be0 fs/btrfs/inode.c:3108
 btrfs_work_helper+0x354/0xb80 fs/btrfs/async-thread.c:325
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
INFO: task syz.0.15:5081 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.15        state:D stack:24016 pid: 5081 ppid:  4806 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11ef/0x43c0 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 wait_on_state fs/btrfs/extent_io.c:868 [inline]
 wait_extent_bit+0x3ad/0x4e0 fs/btrfs/extent_io.c:906
 lock_extent_bits+0x85/0x110 fs/btrfs/extent_io.c:1469
 btrfs_page_mkwrite+0x5cf/0xc80 fs/btrfs/inode.c:8976
 do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
 wp_page_shared+0x16b/0x6d0 mm/memory.c:3259
 handle_pte_fault mm/memory.c:4668 [inline]
 __handle_mm_fault mm/memory.c:4785 [inline]
 handle_mm_fault+0x1f06/0x4410 mm/memory.c:4883
 do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1355
 handle_page_fault arch/x86/mm/fault.c:1443 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1496
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:606
RIP: 0010:copy_user_generic_unrolled+0x89/0xc0 arch/x86/lib/copy_user_64.S:92
Code: 38 4c 89 47 20 4c 89 4f 28 4c 89 57 30 4c 89 5f 38 48 8d 76 40 48 8d 7f 40 ff c9 75 b6 89 d1 83 e2 07 c1 e9 03 74 12 4c 8b 06 <4c> 89 07 48 8d 76 08 48 8d 7f 08 ff c9 75 ee 21 d2 74 10 89 d1 8a
RSP: 0018:ffffc9000121f6a0 EFLAGS: 00050202
RAX: ffffffff83e40901 RBX: 0000000000000038 RCX: 0000000000000007
RDX: 0000000000000000 RSI: ffffc9000121f740 RDI: 00000000200003a0
RBP: 0000000000000000 R08: 0000000000000000 R09: 1ffff92000243eee
R10: dffffc0000000000 R11: fffff52000243eef R12: 00007ffffffff000
R13: 00000000200003d8 R14: ffffc9000121f740 R15: 00000000200003a0
 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline]
 raw_copy_to_user arch/x86/include/asm/uaccess_64.h:58 [inline]
 _copy_to_user+0xf0/0x130 lib/usercopy.c:40
 copy_to_user include/linux/uaccess.h:200 [inline]
 fiemap_fill_next_extent+0x1ba/0x390 fs/ioctl.c:144
 emit_fiemap_extent fs/btrfs/extent_io.c:5468 [inline]
 extent_fiemap+0x120d/0x15b0 fs/btrfs/extent_io.c:5694
 btrfs_fiemap+0xc0/0x110 fs/btrfs/inode.c:8599
 ioctl_fiemap fs/ioctl.c:219 [inline]
 do_vfs_ioctl+0x152d/0x1ef0 fs/ioctl.c:814
 __do_sys_ioctl fs/ioctl.c:872 [inline]
 __se_sys_ioctl+0x83/0x170 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f5ab6f12f69
RSP: 002b:00007f5ab6187058 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f5ab70defa0 RCX: 00007f5ab6f12f69
RDX: 0000000020000380 RSI: 00000000c020660b RDI: 0000000000000004
RBP: 00007f5ab6f96b87 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f5ab70defa0 R15: 00007ffce3f121c8
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/u4:0/9:
 #0: ffff888077a2d138 ((wq_completion)btrfs-endio-write){+.+.}-{0:0}, at: process_one_work+0x761/0x1010 kernel/workqueue.c:-1
 #1: ffffc90000ce7d00 ((work_completion)(&work->normal_work)){+.+.}-{0:0}, at: process_one_work+0x79f/0x1010 kernel/workqueue.c:2285
1 lock held by khungtaskd/27:
 #0: ffffffff8c31f320 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3948:
 #0: ffff88807f429098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900025e62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5df/0x1a70 drivers/tty/n_tty.c:2158
3 locks held by syz.0.15/5081:
 #0: ffff88807b509d28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
 #0: ffff88807b509d28 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2b9/0xc80 arch/x86/mm/fault.c:1296
 #1: ffff88807a19c558 (sb_pagefaults#2){.+.+}-{0:0}, at: do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
 #2: ffff888068b19838 (&ei->i_mmap_lock){.+.+}-{3:3}, at: btrfs_page_mkwrite+0x480/0xc80 fs/btrfs/inode.c:8965
1 lock held by udevd/5108:
 #0: ffff88802063a118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x157/0xa60 block/bdev.c:820
2 locks held by syz.1.648/6440:
 #0: ffff88802063a118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf9/0x7d0 block/bdev.c:915
 #1: ffff88814724e468 (&lo->lo_mutex){+.+.}-{3:3}, at: lo_release+0x4d/0x1f0 drivers/block/loop.c:2071

=============================================

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 04/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe0f/0xe50 kernel/hung_task.c:369
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7 Comm: kworker/0:0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
Workqueue: rcu_gp process_srcu
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline]
RIP: 0010:check_preemption_disabled+0x1f/0x110 lib/smp_processor_id.c:16
Code: 7a 8a 48 c7 c6 e0 06 7a 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 79 3b 45 76 <65> 8b 0d e2 95 45 76 f7 c1 ff ff ff 7f 74 1f 65 48 8b 0c 25 28 00
RSP: 0018:ffffc90000cc7a88 EFLAGS: 00000286
RAX: 0000000000000000 RBX: 0000000000002af9 RCX: ffffffff962dcf00
RDX: 0000000000000087 RSI: ffffffff8a7a06e0 RDI: ffffffff8a7a06a0
RBP: 0000000000000000 R08: ffffc90000cc7927 R09: 1ffff92000198f24
R10: dffffc0000000000 R11: fffff52000198f25 R12: dffffc0000000000
R13: ffffffff96347800 R14: 0000008726fb6242 R15: 0000000000000026
FS:  0000000000000000(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6ae0042000 CR3: 00000000187e0000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 delay_tsc+0x66/0xc0 arch/x86/lib/delay.c:90
 try_check_zero+0x2c7/0x340 kernel/rcu/srcutree.c:702
 srcu_advance_state kernel/rcu/srcutree.c:1227 [inline]
 process_srcu+0x195/0xc10 kernel/rcu/srcutree.c:1325
 process_one_work+0x85f/0x1010 kernel/workqueue.c:2310
 worker_thread+0xaa6/0x1290 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>