[syzbot] [nilfs?] [xfs?] INFO: task hung in xfs_buf_get_map

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 93f3bab4310d Add linux-next specific files for 20251017
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=164183cd980000
kernel config: https://syzkaller.appspot.com/x/.config?x=408308c229eef498
dashboard link: https://syzkaller.appspot.com/bug?extid=d74d844bdcee0902b28a
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15731492580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c955a9337646/disk-93f3bab4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/843962ea5283/vmlinux-93f3bab4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/42360a7c5734/bzImage-93f3bab4.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/79eeb7cc5dde/mount_0.gz
fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=16995de2580000)
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/9596ff3df6a7/mount_4.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d74d84...@syzkaller.appspotmail.com

INFO: task syz.2.368:9928 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.368 state:D stack:20840 pid:9928 tgid:9927 ppid:5959 task_flags:0x440140 flags:0x00080003
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5254 [inline]
__schedule+0x17c4/0x4d60 kernel/sched/core.c:6862
__schedule_loop kernel/sched/core.c:6944 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6959
schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75
___down_common kernel/locking/semaphore.c:268 [inline]
__down_common+0x319/0x6a0 kernel/locking/semaphore.c:293
down+0x80/0xd0 kernel/locking/semaphore.c:100
xfs_buf_lock+0x15d/0x4d0 fs/xfs/xfs_buf.c:993
xfs_buf_find_lock+0x42/0x4c0 fs/xfs/xfs_buf.c:419
xfs_buf_lookup fs/xfs/xfs_buf.c:472 [inline]
xfs_buf_get_map+0x10cf/0x1840 fs/xfs/xfs_buf.c:594
xfs_buf_read_map+0x82/0xa50 fs/xfs/xfs_buf.c:699
xfs_trans_read_buf_map+0x1d7/0x8e0 fs/xfs/xfs_trans_buf.c:304
xfs_trans_read_buf fs/xfs/xfs_trans.h:210 [inline]
xfs_read_agf+0x281/0x5c0 fs/xfs/libxfs/xfs_alloc.c:3376
xfs_alloc_read_agf+0x17c/0xb70 fs/xfs/libxfs/xfs_alloc.c:3411
xfs_alloc_fix_freelist+0x60a/0x1300 fs/xfs/libxfs/xfs_alloc.c:2875
xfs_free_extent_fix_freelist+0x13e/0x240 fs/xfs/libxfs/xfs_alloc.c:3990
xfs_rmap_finish_init_cursor+0xae/0x210 fs/xfs/libxfs/xfs_rmap.c:2645
xfs_rmap_finish_one+0x2a2/0x710 fs/xfs/libxfs/xfs_rmap.c:2708
xfs_rmap_update_finish_item+0x25/0x40 fs/xfs/xfs_rmap_item.c:437
xfs_defer_finish_one+0x5c8/0xcf0 fs/xfs/libxfs/xfs_defer.c:595
xfs_defer_finish_noroll+0x910/0x12d0 fs/xfs/libxfs/xfs_defer.c:707
xfs_trans_commit+0x10b/0x1c0 fs/xfs/xfs_trans.c:921
xfs_attr_set+0xdc6/0x1210 fs/xfs/libxfs/xfs_attr.c:1150
xfs_xattr_set+0x14d/0x250 fs/xfs/xfs_xattr.c:186
__vfs_setxattr+0x43c/0x480 fs/xattr.c:200
__vfs_setxattr_noperm+0x12d/0x660 fs/xattr.c:234
vfs_setxattr+0x16b/0x2f0 fs/xattr.c:321
do_setxattr fs/xattr.c:636 [inline]
filename_setxattr+0x274/0x600 fs/xattr.c:665
path_setxattrat+0x364/0x3a0 fs/xattr.c:713
__do_sys_setxattr fs/xattr.c:747 [inline]
__se_sys_setxattr fs/xattr.c:743 [inline]
__x64_sys_setxattr+0xbc/0xe0 fs/xattr.c:743
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f141038efc9
RSP: 002b:00007f1411141038 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007f14105e5fa0 RCX: 00007f141038efc9
RDX: 00002000000013c0 RSI: 0000200000000140 RDI: 0000200000000100
RBP: 00007f1410411f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000700 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f14105e6038 R14: 00007f14105e5fa0 R15: 00007ffeca4978b8
</TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e13d720 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e13d720 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8e13d720 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5586:
#0: ffff88803370d0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900036bb2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
2 locks held by udevd/5851:
1 lock held by syz-executor/5948:
#0: ffffffff8e1431b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#0: ffffffff8e1431b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:957
2 locks held by syz-executor/5951:
#0: ffff8880334640e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff8880334640e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff8880334640e0 (&type->s_umount_key#53){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:505
#1: ffff88801cab0188 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x3d/0x130 fs/kernfs/dir.c:1712
5 locks held by kworker/u8:9/8967:
4 locks held by syz.2.368/9928:
#0: ffff888026af0420 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:508
#1: ffff8880571d8ab0 (&sb->s_type->i_mutex_key#20){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline]
#1: ffff8880571d8ab0 (&sb->s_type->i_mutex_key#20){+.+.}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
#2: ffff888026af0610 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc+0xd7/0x980 fs/xfs/xfs_trans.c:256
#3: ffff8880571d8898 (&xfs_nondir_ilock_class){++++}-{4:4}, at: xfs_trans_alloc_inode+0x161/0x4a0 fs/xfs/xfs_trans.c:1082
4 locks held by syz.2.368/9964:
#0: ffff888026af0420 (sb_writers#12){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:508
#1: ffff88805722d5b0 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline]
#1: ffff88805722d5b0 (&inode->i_sb->s_type->i_mutex_dir_key){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0 fs/xattr.c:320
#2: ffff888026af0610 (sb_internal#2){.+.+}-{0:0}, at: xfs_trans_alloc+0xd7/0x980 fs/xfs/xfs_trans.c:256
#3: ffff88805722d398 (&xfs_dir_ilock_class){++++}-{4:4}, at: xfs_trans_alloc_inode+0x161/0x4a0 fs/xfs/xfs_trans.c:1082
1 lock held by syz-executor/10238:
2 locks held by syz.3.652/13032:
#0: ffff888031bc20e0 (&type->s_umount_key#52/1){+.+.}-{4:4}, at: alloc_super+0x1bb/0x930 fs/super.c:344
#1: ffff8880b863a058 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:638

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