[v6.1] INFO: task hung in migrate_pages (4)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: f6e38ae624cf Linux 6.1.158
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=13267e0a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=68aa5a3af1cb953a
dashboard link: https://syzkaller.appspot.com/bug?extid=7848b5687ab513fd1d9d
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c1bd671a9def/disk-f6e38ae6.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/fa0af998ea40/vmlinux-f6e38ae6.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e5512d873524/Image-f6e38ae6.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7848b5...@syzkaller.appspotmail.com

INFO: task syz.8.971:9298 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.8.971 state:D stack:0 pid:9298 ppid:5554 flags:0x00000009
Call trace:
__switch_to+0x2f4/0x568 arch/arm64/kernel/process.c:555
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0xddc/0x1b18 kernel/sched/core.c:6561
schedule+0xc4/0x170 kernel/sched/core.c:6637
io_schedule+0x84/0x154 kernel/sched/core.c:8797
folio_wait_bit_common+0x56c/0x9c4 mm/filemap.c:1324
__folio_lock+0x2c/0x3c mm/filemap.c:1687
folio_lock include/linux/pagemap.h:974 [inline]
__migrate_folio_unmap mm/migrate.c:1088 [inline]
migrate_folio_unmap mm/migrate.c:1270 [inline]
migrate_pages_batch mm/migrate.c:1635 [inline]
migrate_pages+0x203c/0x3bbc mm/migrate.c:1843
compact_zone+0x2274/0x3c94 mm/compaction.c:2414
compact_node+0x1d8/0x370 mm/compaction.c:2691
compact_nodes mm/compaction.c:2707 [inline]
sysctl_compaction_handler+0x88/0x108 mm/compaction.c:2749
proc_sys_call_handler+0x3fc/0x69c fs/proc/proc_sysctl.c:602
proc_sys_write+0x2c/0x3c fs/proc/proc_sysctl.c:628
do_iter_readv_writev fs/read_write.c:-1 [inline]
do_iter_write+0x530/0x91c fs/read_write.c:861
vfs_iter_write+0x88/0xac fs/read_write.c:902
iter_file_splice_write+0x500/0xa18 fs/splice.c:685
do_splice_from fs/splice.c:763 [inline]
direct_splice_actor+0xe4/0x134 fs/splice.c:950
splice_direct_to_actor+0x3b4/0x978 fs/splice.c:896
do_splice_direct+0x158/0x244 fs/splice.c:1002
do_sendfile+0x458/0xc88 fs/read_write.c:1255
__do_sys_sendfile64 fs/read_write.c:1317 [inline]
__se_sys_sendfile64 fs/read_write.c:1309 [inline]
__arm64_sys_sendfile64+0x208/0x360 fs/read_write.c:1309
__invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
invoke_syscall+0x98/0x2bc arch/arm64/kernel/syscall.c:52
el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:140
do_el0_svc+0x58/0x13c arch/arm64/kernel/syscall.c:204
el0_svc+0x58/0x138 arch/arm64/kernel/entry-common.c:637
el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:655
el0t_64_sync+0x18c/0x190 arch/arm64/kernel/entry.S:585

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
#0: ffff800015297870 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
#0: ffff800015298090 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x40/0xbb4 kernel/rcu/tasks.h:517
1 lock held by khungtaskd/28:
#0: ffff800015296f00 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0xc/0x44 include/linux/rcupdate.h:349
2 locks held by getty/4080:
#0: ffff0000d8860098 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
#1: ffff80001ceb62f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x2ec/0xf9c drivers/tty/n_tty.c:2198
3 locks held by kworker/0:4/4366:
#0: ffff0000c0020938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x6b4/0x13a8 kernel/workqueue.c:2265
#1: ffff800020af7c20 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work+0x6f8/0x13a8 kernel/workqueue.c:2267
#2: ffff0000dc237240 (&data->fib_lock){+.+.}-{3:3}, at: nsim_fib_event_work+0x1c8/0x263c drivers/net/netdevsim/fib.c:1491
1 lock held by udevd/4642:
#0: ffff0000cebf04c8 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_get_by_dev+0x118/0x8cc block/bdev.c:815
3 locks held by kworker/u4:15/5402:
1 lock held by syz.8.971/9298:
#0: ffff0000ca37a460 (sb_writers#4){.+.+}-{0:0}, at: do_sendfile+0x43c/0xc88 fs/read_write.c:1254
2 locks held by syz-executor/13939:
1 lock held by sed/14188:

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