[syzbot] [bcachefs?] INFO: task hung in bch2_mark_pagecache_unallocated (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b5db4add5e77 Merge branch 'for-next/core' into for-kernelci
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=1369627c580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d2ae34a0711ff2f1
dashboard link: https://syzkaller.appspot.com/bug?extid=94b822fda1fb3f24f1da
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14cc0d34580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6eee2232d5c1/disk-b5db4add.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a8b00f2f1234/vmlinux-b5db4add.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fc0d466f156c/Image-b5db4add.gz.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/efd7fb7b4339/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+94b822...@syzkaller.appspotmail.com

INFO: task syz.1.152:8462 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.152 state:D stack:0 pid:8462 tgid:8423 ppid:6684 task_flags:0x400140 flags:0x00000011
Call trace:
__switch_to+0x418/0x87c arch/arm64/kernel/process.c:741 (T)
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x13b0/0x2864 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0xb4/0x230 kernel/sched/core.c:7058
io_schedule+0x84/0xf0 kernel/sched/core.c:7903
folio_wait_bit_common+0x56c/0x9e0 mm/filemap.c:1317
__folio_lock+0x2c/0x3c mm/filemap.c:1675
folio_lock include/linux/pagemap.h:1133 [inline]
bch2_mark_pagecache_unallocated+0x310/0x6c8 fs/bcachefs/fs-io-pagecache.c:275
bch2_remap_file_range+0x598/0xb70 fs/bcachefs/fs-io.c:933
vfs_clone_file_range+0x62c/0xb68 fs/remap_range.c:403
ioctl_file_clone fs/ioctl.c:240 [inline]
ioctl_file_clone_range fs/ioctl.c:258 [inline]
do_vfs_ioctl+0xb84/0x1834 fs/ioctl.c:545
__do_sys_ioctl fs/ioctl.c:596 [inline]
__se_sys_ioctl fs/ioctl.c:584 [inline]
__arm64_sys_ioctl+0xe4/0x1c4 fs/ioctl.c:584
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596
INFO: task syz.1.152:8464 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.152 state:D stack:0 pid:8464 tgid:8423 ppid:6684 task_flags:0x440040 flags:0x00000001
Call trace:
__switch_to+0x418/0x87c arch/arm64/kernel/process.c:741 (T)
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x13b0/0x2864 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0xb4/0x230 kernel/sched/core.c:7058
__bch2_two_state_lock+0x1b4/0x2f0 fs/bcachefs/two_state_shared_lock.c:7
bch2_two_state_lock fs/bcachefs/two_state_shared_lock.h:55 [inline]
bch2_readahead+0xbc8/0xd88 fs/bcachefs/fs-io-buffered.c:296
read_pages+0x13c/0x4c4 mm/readahead.c:160
page_cache_ra_order+0x7a0/0xb7c mm/readahead.c:512
page_cache_sync_ra+0x580/0x73c mm/readahead.c:619
filemap_get_pages+0x2f4/0x19c8 mm/filemap.c:2603
filemap_splice_read+0x454/0xad8 mm/filemap.c:2991
do_splice_read fs/splice.c:982 [inline]
splice_file_to_pipe+0x374/0x5a8 fs/splice.c:1292
do_sendfile+0x37c/0x658 fs/read_write.c:1376
__do_sys_sendfile64 fs/read_write.c:1431 [inline]
__se_sys_sendfile64 fs/read_write.c:1417 [inline]
__arm64_sys_sendfile64+0x1b4/0x274 fs/read_write.c:1417
__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

Showing all locks held in the system:
2 locks held by kworker/u8:0/12:
1 lock held by khungtaskd/32:
#0: ffff80008f9d9620 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire+0x4/0x48 include/linux/rcupdate.h:330
1 lock held by klogd/6160:
2 locks held by getty/6313:
#0: ffff0000d35390a0 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
#1: ffff800099e8e2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x34c/0xfa4 drivers/tty/n_tty.c:2222
1 lock held by syz-executor/6571:
#0: ffff0000c696fc68 (&pipe->mutex){+.+.}-{4:4}, at: pipe_release+0x54/0x2fc fs/pipe.c:727
2 locks held by syz.1.152/8462:
#0: ffff0000cf3a0428 (sb_writers#11){.+.+}-{0:0}, at: ioctl_file_clone fs/ioctl.c:240 [inline]
#0: ffff0000cf3a0428 (sb_writers#11){.+.+}-{0:0}, at: ioctl_file_clone_range fs/ioctl.c:258 [inline]
#0: ffff0000cf3a0428 (sb_writers#11){.+.+}-{0:0}, at: do_vfs_ioctl+0xb84/0x1834 fs/ioctl.c:545
#1: ffff0000f9f89078 (&sb->s_type->i_mutex_key#20){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:870 [inline]
#1: ffff0000f9f89078 (&sb->s_type->i_mutex_key#20){+.+.}-{4:4}, at: lock_two_nondirectories+0xc4/0x150 fs/inode.c:1232
2 locks held by syz.1.152/8464:
#0: ffff0000c696fc68 (&pipe->mutex){+.+.}-{4:4}, at: pipe_lock+0x68/0x98 fs/pipe.c:91
#1: ffff0000f9f89218 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: filemap_invalidate_lock_shared include/linux/fs.h:935 [inline]
#1: ffff0000f9f89218 (mapping.invalidate_lock#3){.+.+}-{4:4}, at: page_cache_ra_order+0x268/0xb7c mm/readahead.c:488

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



---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup