INFO: task syz.0.15:5305 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: 5305 ppid:  5181 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11bb/0x4390 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+0x39b/0x4d0 fs/btrfs/extent_io.c:906
 lock_extent_bits+0x82/0x110 fs/btrfs/extent_io.c:1469
 btrfs_page_mkwrite+0x5b1/0xc50 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+0x1eca/0x43c0 mm/memory.c:4883
 do_user_addr_fault+0x489/0xc80 arch/x86/mm/fault.c:1357
 handle_page_fault arch/x86/mm/fault.c:1445 [inline]
 exc_page_fault+0x60/0x100 arch/x86/mm/fault.c:1501
 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:ffffc9000324f6a0 EFLAGS: 00050202
RAX: ffffffff83dadd01 RBX: 0000000000000038 RCX: 0000000000000007
RDX: 0000000000000000 RSI: ffffc9000324f740 RDI: 00000000200003a0
RBP: 0000000000000000 R08: 0000000000000000 R09: fffff52000649eef
R10: fffff52000649eef R11: 1ffff92000649ee8 R12: 00007ffffffff000
R13: 00000000200003d8 R14: ffffc9000324f740 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+0x19d/0x360 fs/ioctl.c:144
 emit_fiemap_extent fs/btrfs/extent_io.c:5460 [inline]
 extent_fiemap+0x10ff/0x14f0 fs/btrfs/extent_io.c:5686
 btrfs_fiemap+0xc0/0x110 fs/btrfs/inode.c:8599
 ioctl_fiemap fs/ioctl.c:219 [inline]
 do_vfs_ioctl+0x1464/0x1de0 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: 0033:0x7f15c9a26ed9
RSP: 002b:00007f15c8ca5058 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f15c9becfa0 RCX: 00007f15c9a26ed9
RDX: 0000000020000380 RSI: 00000000c020660b RDI: 0000000000000004
RBP: 00007f15c9a9acc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f15c9becfa0 R15: 00007ffd7c589d58
 </TASK>

Showing all locks held in the system:
1 lock held by ksoftirqd/0/14:
 #0: ffff8880b903a358 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x26/0x140 kernel/sched/core.c:475
1 lock held by khungtaskd/27:
 #0: ffffffff8c11c660 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
1 lock held by udevd/3562:
 #0: ffff88801fbba118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x157/0xa60 block/bdev.c:820
2 locks held by getty/3952:
 #0: ffff88814d3a0098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002cf62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x5ba/0x1a30 drivers/tty/n_tty.c:2158
2 locks held by kworker/0:7/4272:
 #0: ffff888016872138 ((wq_completion)rcu_gp){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90002f3fd00 ((work_completion)(&rew.rew_work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
3 locks held by kworker/0:25/5293:
 #0: ffff888016870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc900032ffd00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
 #2: ffffffff8c1210e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:290 [inline]
 #2: ffffffff8c1210e8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x347/0x6b0 kernel/rcu/tree_exp.h:845
3 locks held by syz.0.15/5305:
 #0: ffff88807d6f9628 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
 #0: ffff88807d6f9628 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2b9/0xc80 arch/x86/mm/fault.c:1298
 #1: ffff8880754b0558 (sb_pagefaults#2){.+.+}-{0:0}, at: do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
 #2: ffff888068569838 (&ei->i_mmap_lock){.+.+}-{3:3}, at: btrfs_page_mkwrite+0x461/0xc50 fs/btrfs/inode.c:8965
2 locks held by syz.1.537/6407:
 #0: ffff88801fbba118 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf9/0x7d0 block/bdev.c:915
 #1: ffff88801fb68468 (&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 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x397/0x3d0 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: 3562 Comm: udevd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:link_path_walk+0x675/0xd40 fs/namei.c:2313
Code: 4c 89 f7 e8 3d c2 f1 ff 4d 8b 3e 31 f6 48 8b 7c 24 10 e8 fe 4a 00 00 48 85 c0 0f 85 48 01 00 00 48 8b 44 24 78 42 80 3c 28 00 <74> 08 4c 89 e7 e8 11 c2 f1 ff 4d 8b 34 24 4c 89 f0 48 c1 e8 03 42
RSP: 0018:ffffc90002d6fa60 EFLAGS: 00000246
RAX: 1ffff920005adf8d RBX: dffffc0000000000 RCX: af4d88e3d6ea7700
RDX: 0000000000000010 RSI: ffffc90002d6f9f0 RDI: ffffc90002d6fc90
RBP: ffffc90002d6fb88 R08: dffffc0000000000 R09: fffff520005adf8e
R10: fffff520005adf8e R11: 1ffff920005adf8c R12: ffffc90002d6fc68
R13: dffffc0000000000 R14: ffff888076f84446 R15: ffff888076f84446
FS:  00007f74907d3880(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f70ecd90320 CR3: 000000007cf71000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 path_lookupat+0x9d/0x440 fs/namei.c:2454
 filename_lookup+0x1e2/0x4f0 fs/namei.c:2484
 user_path_at_empty+0x40/0x190 fs/namei.c:2883
 do_readlinkat+0xd4/0x480 fs/stat.c:442
 __do_sys_readlink fs/stat.c:475 [inline]
 __se_sys_readlink fs/stat.c:472 [inline]
 __x64_sys_readlink+0x7b/0x90 fs/stat.c:472
 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: 0033:0x7f749092f3a7
Code: 00 00 90 48 83 ec 10 48 63 ff 45 31 c9 45 31 c0 6a 00 31 c9 e8 8a 20 f9 ff 48 83 c4 18 c3 0f 1f 44 00 00 b8 59 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 21 ba 0d 00 f7 d8 64 89 02 48
RSP: 002b:00007ffc3d15ed58 EFLAGS: 00000246 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00007ffc3d15f230 RCX: 00007f749092f3a7
RDX: 0000000000000400 RSI: 00007ffc3d15ed60 RDI: 00007ffc3d15f230
RBP: 00007ffc3d15ed60 R08: 0000563f504b7c94 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000400
R13: 00000000000000fe R14: 0000563f26d4cbe0 R15: 00007ffc3d15fd30
 </TASK>