INFO: task syz-executor:4717 blocked for more than 143 seconds.
      Not tainted 5.15.178-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor    state:D
 stack:20824 pid: 4717 ppid:     1 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5027 [inline]
 __schedule+0x12c4/0x45b0 kernel/sched/core.c:6373
 schedule+0x11b/0x1f0 kernel/sched/core.c:6456
 wb_wait_for_completion+0x164/0x290 fs/fs-writeback.c:191
 sync_inodes_sb+0x293/0xab0 fs/fs-writeback.c:2770
 sync_filesystem+0x16b/0x220 fs/sync.c:64
 generic_shutdown_super+0x6b/0x310 fs/super.c:448
 kill_block_super+0x7a/0xe0 fs/super.c:1427
 deactivate_locked_super+0xa0/0x110 fs/super.c:335
 cleanup_mnt+0x44e/0x500 fs/namespace.c:1143
 task_work_run+0x129/0x1a0 kernel/task_work.c:188
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop+0x106/0x130 kernel/entry/common.c:181
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:214
 __syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
 syscall_exit_to_user_mode+0x5d/0x240 kernel/entry/common.c:307
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc295637a47
RSP: 002b:00007fffc952e818 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fc2956a91cc RCX: 00007fc295637a47
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007fffc952e8d0
RBP: 00007fffc952e8d0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007fffc952f950
R13: 00007fc2956a91cc R14: 000000000001c74e R15: 00007fffc952f990
 </TASK>

Showing all locks held in the system:
4 locks held by kworker/u4:0/9:
 #0: 
ffff88801bd89138
 (
(wq_completion)writeback
){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90000ce7d20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: 
ffff888026152650 (sb_internal#2){.+.+}-{0:0}, at: xfs_bmapi_convert_delalloc+0x20f/0x1180 fs/xfs/libxfs/xfs_bmap.c:4573
 #3: ffff888075ce5368 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_bmapi_convert_delalloc+0x23c/0x1180 fs/xfs/libxfs/xfs_bmap.c:4578
1 lock held by khungtaskd/27:
 #0: 
ffffffff8cb1fce0
 (
rcu_read_lock
){....}-{1:2}
, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:1/144:
 #0: 
ffff88801bd89138
 (
(wq_completion)writeback
){+.+.}-{0:0}
, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: 
ffffc900011efd20
 (
(work_completion)(&(&wb->dwork)->work)
){+.+.}-{0:0}
, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: 
ffff88807d562650
 (
sb_internal
#2
){.+.+}-{0:0}
, at: xfs_bmapi_convert_delalloc+0x20f/0x1180 fs/xfs/libxfs/xfs_bmap.c:4573
 #3: 
ffff888071bce9e8
 (
&xfs_nondir_ilock_class
){++++}-{3:3}
, at: xfs_bmapi_convert_delalloc+0x23c/0x1180 fs/xfs/libxfs/xfs_bmap.c:4578
4 locks held by kworker/u4:2/154:
 #0: ffff88801bd89138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: ffffc90001b07d20 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}
, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: 
ffff888028e5e650
 (
sb_internal
#2
){.+.+}-{0:0}
, at: xfs_bmapi_convert_delalloc+0x20f/0x1180 fs/xfs/libxfs/xfs_bmap.c:4573
 #3: 
ffff888071bc80e8
 (
&xfs_nondir_ilock_class
){++++}-{3:3}
, at: xfs_bmapi_convert_delalloc+0x23c/0x1180 fs/xfs/libxfs/xfs_bmap.c:4578
4 locks held by kworker/u4:3/157:
 #0: 
ffff88801bd89138
 (
(wq_completion)writeback
){+.+.}-{0:0}
, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: 
ffffc90001b37d20
 (
(work_completion)(&(&wb->dwork)->work)
){+.+.}-{0:0}
, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: 
ffff888076e9a650
 (
sb_internal
#2
){.+.+}-{0:0}
, at: xfs_bmapi_convert_delalloc+0x20f/0x1180 fs/xfs/libxfs/xfs_bmap.c:4573
 #3: 
ffff888071bcf168
 (
&xfs_nondir_ilock_class
){++++}-{3:3}
, at: xfs_bmapi_convert_delalloc+0x23c/0x1180 fs/xfs/libxfs/xfs_bmap.c:4578
5 locks held by kworker/0:2/1111:
4 locks held by kworker/u4:5/1445:
 #0: 
ffff88801bd89138
 (
(wq_completion)writeback
){+.+.}-{0:0}
, at: process_one_work+0x78a/0x10c0 kernel/workqueue.c:2283
 #1: 
ffffc90004f07d20
 (
(work_completion)(&(&wb->dwork)->work)
){+.+.}-{0:0}
, at: process_one_work+0x7d0/0x10c0 kernel/workqueue.c:2285
 #2: ffff8881470e4650 (sb_internal#2){.+.+}-{0:0}, at: xfs_bmapi_convert_delalloc+0x20f/0x1180 fs/xfs/libxfs/xfs_bmap.c:4573
 #3: ffff888075ce1768 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_bmapi_convert_delalloc+0x23c/0x1180 fs/xfs/libxfs/xfs_bmap.c:4578
2 locks held by getty/3928:
 #0: ffff88802caff098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc90002cd62e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6af/0x1db0 drivers/tty/n_tty.c:2158
2 locks held by syz-executor/4717:
 #0: ffff8881470e40e0 (&type->s_umount_key#52){+.+.}-{3:3}
, at: deactivate_super+0xa9/0xe0 fs/super.c:365
 #1: ffff888020d487d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff888020d487d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x274/0xab0 fs/fs-writeback.c:2768
2 locks held by syz-executor/5005:
 #0: ffff888028e5e0e0 (&type->s_umount_key#52){+.+.}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:365
 #1: 
ffff888020d4e7d8
 (
&bdi->wb_switch_rwsem
){+.+.}-{3:3}
, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
, at: sync_inodes_sb+0x274/0xab0 fs/fs-writeback.c:2768
2 locks held by syz-executor/5029:
 #0: 
ffff8880261520e0
 (
&type->s_umount_key#52){+.+.}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:365
 #1: ffff888020e647d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff888020e647d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x274/0xab0 fs/fs-writeback.c:2768
2 locks held by syz-executor/5066:
 #0: 
ffff88807d5620e0
 (
&type->s_umount_key
#52
){+.+.}-{3:3}
, at: deactivate_super+0xa9/0xe0 fs/super.c:365
 #1: ffff888020e727d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
 #1: ffff888020e727d8 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0x274/0xab0 fs/fs-writeback.c:2768
2 locks held by syz-executor/5119:
 #0: 
ffff888076e9a0e0
 (
&type->s_umount_key
#52){+.+.}-{3:3}, at: deactivate_super+0xa9/0xe0 fs/super.c:365
 #1: 
ffff888020e887d8
 (
&bdi->wb_switch_rwsem
){+.+.}-{3:3}
, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:362 [inline]
, at: sync_inodes_sb+0x274/0xab0 fs/fs-writeback.c:2768

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

NMI backtrace for cpu 1
CPU: 1 PID: 27 Comm: khungtaskd Not tainted 5.15.178-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x46a/0x4a0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x181/0x2a0 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:210 [inline]
 watchdog+0xe72/0xeb0 kernel/hung_task.c:295
 kthread+0x3f6/0x4f0 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: 1445 Comm: kworker/u4:5 Not tainted 5.15.178-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Workqueue: writeback wb_workfn (flush-7:0)
RIP: 0010:io_serial_in+0x72/0xb0 drivers/tty/serial/8250/8250_port.c:461
Code: 14 55 fa fc 89 e9 41 d3 e6 48 83 c3 40 48 89 d8 48 c1 e8 03 42 80 3c 38 00 74 08 48 89 df e8 55 3d 44 fd 44 03 33 44 89 f2 ec <0f> b6 c0 5b 41 5e 41 5f 5d c3 89 e9 80 e1 07 38 c1 7c ad 48 89 ef
RSP: 0018:ffffc90004f054b0 EFLAGS: 00000002
RAX: 1ffffffff2db7300 RBX: ffffffff96db9a00 RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020
RBP: 0000000000000000 R08: ffffffff84863072 R09: 0000000000000003
R10: ffffffffffffffff R11: dffffc0000000001 R12: 1ffffffff2db738d
R13: ffffffff96db99c0 R14: 00000000000003fd R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f85eca21866 CR3: 000000002b8ad000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <NMI>
 </NMI>
 <TASK>
 serial_in drivers/tty/serial/8250/8250.h:116 [inline]
 wait_for_xmitr+0xec/0x260 drivers/tty/serial/8250/8250_port.c:2069
 serial8250_console_putchar+0x19/0x50 drivers/tty/serial/8250/8250_port.c:3301
 uart_console_write+0xa9/0x100 drivers/tty/serial/serial_core.c:1981
 serial8250_console_write+0xc8e/0x1180 drivers/tty/serial/8250/8250_port.c:3378
 console_unlock+0xced/0x12b0 kernel/printk/printk.c:2744
 vprintk_emit+0xbf/0x150 kernel/printk/printk.c:2274
 _printk+0xd1/0x120 kernel/printk/printk.c:2299
 __xfs_printk fs/xfs/xfs_message.c:24 [inline]
 xfs_buf_alert_ratelimited+0x236/0x240 fs/xfs/xfs_message.c:139
 xfs_buf_ioerror_alert fs/xfs/xfs_buf.c:1338 [inline]
 xfs_buf_read_map+0x5df/0xa00 fs/xfs/xfs_buf.c:817
 xfs_trans_read_buf_map+0x25c/0xa60 fs/xfs/xfs_trans_buf.c:289
 xfs_trans_read_buf fs/xfs/xfs_trans.h:210 [inline]
 xfs_btree_read_buf_block+0x26e/0x370 fs/xfs/libxfs/xfs_btree.c:1354
 xfs_btree_lookup_get_block+0x327/0x790 fs/xfs/libxfs/xfs_btree.c:1825
 xfs_btree_lookup+0x3b5/0x13b0 fs/xfs/libxfs/xfs_btree.c:1916
 xfs_alloc_lookup_eq+0x5e/0x110 fs/xfs/libxfs/xfs_alloc.c:153
 xfs_alloc_fixup_trees+0x1a7/0xa80 fs/xfs/libxfs/xfs_alloc.c:480
 xfs_alloc_cur_finish+0xe6/0x4d0 fs/xfs/libxfs/xfs_alloc.c:932
 xfs_alloc_ag_vextent_near+0x1179/0x1710 fs/xfs/libxfs/xfs_alloc.c:1643
 xfs_alloc_ag_vextent+0xa5/0x780 fs/xfs/libxfs/xfs_alloc.c:1149
 xfs_alloc_vextent+0x1103/0x1b00 fs/xfs/libxfs/xfs_alloc.c:3212
 xfs_bmap_btalloc+0x1477/0x2bf0 fs/xfs/libxfs/xfs_bmap.c:3718
 xfs_bmapi_allocate+0x4f4/0xe30
 xfs_bmapi_convert_delalloc+0x84c/0x1180 fs/xfs/libxfs/xfs_bmap.c:4636
 xfs_convert_blocks fs/xfs/xfs_aops.c:245 [inline]
 xfs_map_blocks+0xa9e/0x1520 fs/xfs/xfs_aops.c:366
 iomap_writepage_map fs/iomap/buffered-io.c:1320 [inline]
 iomap_do_writepage+0x63c/0x21c0 fs/iomap/buffered-io.c:1485
 write_cache_pages+0xa97/0x1160 mm/page-writeback.c:2277
 iomap_writepages+0x64/0x240 fs/iomap/buffered-io.c:1516
 xfs_vm_writepages+0x127/0x180 fs/xfs/xfs_aops.c:488
 do_writepages+0x481/0x730 mm/page-writeback.c:2386
 __writeback_single_inode+0x15b/0xe30 fs/fs-writeback.c:1647
 writeback_sb_inodes+0xbce/0x1a40 fs/fs-writeback.c:1930
 wb_writeback+0x451/0xc50 fs/fs-writeback.c:2104
 wb_do_writeback fs/fs-writeback.c:2247 [inline]
 wb_workfn+0x46c/0x1130 fs/fs-writeback.c:2288
 process_one_work+0x8a1/0x10c0 kernel/workqueue.c:2310
 worker_thread+0xaca/0x1280 kernel/workqueue.c:2457
 kthread+0x3f6/0x4f0 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>