INFO: task kworker/u4:6:4284 blocked for more than 144 seconds.
      Not tainted 5.15.189-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:6    state:D stack:21344 pid: 4284 ppid:     2 flags:0x00004000
Workqueue: writeback wb_workfn (flush-btrfs-4)
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1e0 kernel/sched/core.c:6459
 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
 find_lock_delalloc_range+0x251/0x4f0 fs/btrfs/extent_io.c:2047
 writepage_delalloc+0xf8/0x360 fs/btrfs/extent_io.c:3794
 __extent_writepage+0x51f/0xb00 fs/btrfs/extent_io.c:4107
 extent_write_cache_pages fs/btrfs/extent_io.c:5029 [inline]
 extent_writepages+0x9c4/0x13b0 fs/btrfs/extent_io.c:5156
 do_writepages+0x48d/0x6d0 mm/page-writeback.c:2386
 __writeback_single_inode+0x153/0xda0 fs/fs-writeback.c:1647
 writeback_sb_inodes+0x9fe/0x1610 fs/fs-writeback.c:1930
 wb_writeback+0x443/0xb90 fs/fs-writeback.c:2104
 wb_do_writeback fs/fs-writeback.c:2247 [inline]
 wb_workfn+0x423/0xe60 fs/fs-writeback.c:2288
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 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.2.150:4952 blocked for more than 146 seconds.
      Not tainted 5.15.189-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.150       state:D stack:23328 pid: 4952 ppid:  4189 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1e0 kernel/sched/core.c:6459
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8484
 wait_on_page_bit_common+0x815/0xe00 mm/filemap.c:1356
 lock_page include/linux/pagemap.h:625 [inline]
 btrfs_page_mkwrite+0x4f7/0xc50 fs/btrfs/inode.c:8966
 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:ffffc900030dfcc0 EFLAGS: 00050203
RAX: ffffffff83da7d01 RBX: 0000000000000014 RCX: 0000000000000002
RDX: 0000000000000004 RSI: ffffc900030dfda0 RDI: 00002000000000c0
RBP: 0000000000000000 R08: 0000000200000003 R09: fffff5200061bfb7
R10: fffff5200061bfb7 R11: 1ffff9200061bfb4 R12: 00007ffffffff000
R13: 00002000000000d4 R14: ffffc900030dfda0 R15: 00002000000000c0
 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]
 video_put_user drivers/media/v4l2-core/v4l2-ioctl.c:3203 [inline]
 video_usercopy+0xc3d/0xf00 drivers/media/v4l2-core/v4l2-ioctl.c:3361
 v4l2_ioctl+0x183/0x1d0 drivers/media/v4l2-core/v4l2-dev.c:364
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfa/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: 0033:0x7f2a1e032be9
RSP: 002b:00007f2a1c29a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2a1e259fa0 RCX: 00007f2a1e032be9
RDX: 00002000000000c0 RSI: 00000000c0145608 RDI: 0000000000000007
RBP: 00007f2a1e0b5e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2a1e25a038 R14: 00007f2a1e259fa0 R15: 00007fff50b885c8
 </TASK>
INFO: task syz.2.150:4987 blocked for more than 146 seconds.
      Not tainted 5.15.189-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.150       state:D stack:24872 pid: 4987 ppid:  4189 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1e0 kernel/sched/core.c:6459
 io_schedule+0x7c/0xd0 kernel/sched/core.c:8484
 wait_on_page_bit_common+0x815/0xe00 mm/filemap.c:1356
 lock_page include/linux/pagemap.h:625 [inline]
 btrfs_page_mkwrite+0x4f7/0xc50 fs/btrfs/inode.c:8966
 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:ffffc900031776a0 EFLAGS: 00050202
RAX: ffffffff83da7d01 RBX: 0000000000000038 RCX: 0000000000000007
RDX: 0000000000000000 RSI: ffffc90003177740 RDI: 00002000000002a0
RBP: 0000000000000000 R08: 0000000000000000 R09: fffff5200062eeef
R10: fffff5200062eeef R11: 1ffff9200062eee8 R12: 00007ffffffff000
R13: 00002000000002d8 R14: ffffc90003177740 R15: 00002000000002a0
 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:5447 [inline]
 extent_fiemap+0x1055/0x14f0 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: 0033:0x7f2a1e032be9
RSP: 002b:00007f2a1c279038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2a1e25a090 RCX: 00007f2a1e032be9
RDX: 0000200000000280 RSI: 00000000c020660b RDI: 0000000000000004
RBP: 00007f2a1e0b5e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2a1e25a128 R14: 00007f2a1e25a090 R15: 00007fff50b885c8
 </TASK>
INFO: task syz.2.150:4991 blocked for more than 147 seconds.
      Not tainted 5.15.189-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.150       state:D stack:27616 pid: 4991 ppid:  4189 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5030 [inline]
 __schedule+0x11b8/0x43b0 kernel/sched/core.c:6376
 schedule+0x11b/0x1e0 kernel/sched/core.c:6459
 wb_wait_for_completion+0x164/0x290 fs/fs-writeback.c:191
 __writeback_inodes_sb_nr+0x1f3/0x240 fs/fs-writeback.c:2684
 sync_filesystem+0x9f/0x220 fs/sync.c:54
 btrfs_remount+0x222/0x15b0 fs/btrfs/super.c:1927
 reconfigure_super+0x219/0x880 fs/super.c:938
 do_remount fs/namespace.c:2670 [inline]
 path_mount+0xd3e/0x1020 fs/namespace.c:3336
 do_mount fs/namespace.c:3357 [inline]
 __do_sys_mount fs/namespace.c:3565 [inline]
 __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3542
 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: 0033:0x7f2a1e032be9
RSP: 002b:00007f2a1c258038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f2a1e25a180 RCX: 00007f2a1e032be9
RDX: 0000000000000000 RSI: 00002000000001c0 RDI: 0000000000000000
RBP: 00007f2a1e0b5e19 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000010f482a R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2a1e25a218 R14: 00007f2a1e25a180 R15: 00007fff50b885c8
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8c11c360 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
2 locks held by getty/3944:
 #0: ffff88802be86098 (&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 syz-executor/4184:
 #0: ffff88801ff11918 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0xf9/0x7d0 block/bdev.c:915
 #1: ffff88814766f468 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0xaa/0xb90 drivers/block/loop.c:1366
2 locks held by kworker/u4:6/4284:
 #0: ffff88814299d938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x760/0x1000 kernel/workqueue.c:-1
 #1: ffffc90004397d00 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7a3/0x1000 kernel/workqueue.c:2285
3 locks held by syz.2.150/4952:
 #0: ffff88807d0cce28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
 #0: ffff88807d0cce28 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2b9/0xc80 arch/x86/mm/fault.c:1298
 #1: ffff888074104558 (sb_pagefaults#2){.+.+}-{0:0}, at: do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
 #2: ffff88805f1335a8 (&ei->i_mmap_lock){++++}-{3:3}, at: btrfs_page_mkwrite+0x461/0xc50 fs/btrfs/inode.c:8965
3 locks held by syz.2.150/4987:
 #0: ffff88807d0cce28 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_trylock include/linux/mmap_lock.h:136 [inline]
 #0: ffff88807d0cce28 (&mm->mmap_lock){++++}-{3:3}, at: do_user_addr_fault+0x2b9/0xc80 arch/x86/mm/fault.c:1298
 #1: ffff888074104558 (sb_pagefaults#2){.+.+}-{0:0}, at: do_page_mkwrite+0x168/0x3c0 mm/memory.c:2922
 #2: ffff88805f1335a8 (&ei->i_mmap_lock){++++}-{3:3}, at: btrfs_page_mkwrite+0x461/0xc50 fs/btrfs/inode.c:8965
1 lock held by syz.2.150/4991:
 #0: ffff8880741040e0 (&type->s_umount_key#60){+.+.}-{3:3}, at: do_remount fs/namespace.c:2667 [inline]
 #0: ffff8880741040e0 (&type->s_umount_key#60){+.+.}-{3:3}, at: path_mount+0xcf8/0x1020 fs/namespace.c:3336

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 4662 Comm: kworker/u4:13 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: bat_events batadv_nc_worker
RIP: 0010:mark_held_locks kernel/locking/lockdep.c:4181 [inline]
RIP: 0010:__trace_hardirqs_on_caller kernel/locking/lockdep.c:4211 [inline]
RIP: 0010:lockdep_hardirqs_on_prepare+0x24e/0x760 kernel/locking/lockdep.c:4278
Code: 83 f8 01 ba 03 00 00 00 83 da 00 48 8b 7c 24 10 4c 89 fe e8 84 e8 00 00 48 ba 00 00 00 00 00 fc ff df 85 c0 0f 84 a2 01 00 00 <41> 0f b6 04 16 84 c0 75 5b 49 ff c5 48 63 03 49 83 c7 28 49 83 c4
RSP: 0018:ffffc9000307f9c0 EFLAGS: 00000002
RAX: 0000000000000001 RBX: ffff8880298aa8a8 RCX: ffffffff815cacb4
RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffffffff8ffb71a8
RBP: ffffc9000307fa80 R08: dffffc0000000000 R09: fffffbfff1ff6e36
R10: fffffbfff1ff6e36 R11: 1ffffffff1ff6e35 R12: ffff8880298aa8d0
R13: 0000000000000000 R14: 1ffff11005315515 R15: ffff8880298aa8b0
FS:  0000000000000000(0000) GS:ffff8880b9100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9f096efad8 CR3: 000000007ea30000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 trace_hardirqs_on+0x67/0x80 kernel/trace/trace_preemptirq.c:49
 __local_bh_enable_ip+0x12a/0x1b0 kernel/softirq.c:406
 spin_unlock_bh include/linux/spinlock.h:408 [inline]
 batadv_nc_purge_paths+0x316/0x3b0 net/batman-adv/network-coding.c:475
 batadv_nc_worker+0x327/0x5c0 net/batman-adv/network-coding.c:726
 process_one_work+0x863/0x1000 kernel/workqueue.c:2310
 worker_thread+0xaa8/0x12a0 kernel/workqueue.c:2457
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>