[syzbot] [ocfs2?] possible deadlock in ocfs2_extend_dir

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 4d349ee5c778 Merge tag 'arm64-fixes' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12e42d5a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=93740e6c6567fcec
dashboard link: https://syzkaller.appspot.com/bug?extid=67b90111784a3eac8c04
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/07750ef5994f/disk-4d349ee5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1dcac8a91bbe/vmlinux-4d349ee5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9818acdf7c39/bzImage-4d349ee5.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+67b901...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G L
------------------------------------------------------
syz-executor/22669 is trying to acquire lock:
ffff88807a2dea20 (&ocfs2_file_ip_alloc_sem_key){++++}-{4:4}, at: ocfs2_expand_inline_dir fs/ocfs2/dir.c:2846 [inline]
ffff88807a2dea20 (&ocfs2_file_ip_alloc_sem_key){++++}-{4:4}, at: ocfs2_extend_dir+0x69a/0x4a60 fs/ocfs2/dir.c:3227

but task is already holding lock:
ffff88807a2ded80 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
ffff88807a2ded80 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_lookup_lock_orphan_dir+0xec/0x2e0 fs/ocfs2/namei.c:2132

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}:
down_write+0x96/0x200 kernel/locking/rwsem.c:1590
inode_lock include/linux/fs.h:1028 [inline]
ocfs2_del_inode_from_orphan+0x12e/0x7a0 fs/ocfs2/namei.c:2731
ocfs2_dio_end_io_write fs/ocfs2/aops.c:2305 [inline]
ocfs2_dio_end_io+0x543/0x1210 fs/ocfs2/aops.c:2403
dio_complete+0x25b/0x790 fs/direct-io.c:281
__blockdev_direct_IO+0x2cb0/0x32f0 fs/direct-io.c:1303
ocfs2_direct_IO+0x251/0x2c0 fs/ocfs2/aops.c:2440
generic_file_direct_write+0x1db/0x3e0 mm/filemap.c:4248
__generic_file_write_iter+0x11d/0x230 mm/filemap.c:4417
ocfs2_file_write_iter+0x1663/0x1ed0 fs/ocfs2/file.c:2476
iter_file_splice_write+0x9a1/0x10f0 fs/splice.c:736
do_splice_from fs/splice.c:936 [inline]
direct_splice_actor+0x101/0x160 fs/splice.c:1159
splice_direct_to_actor+0x53a/0xc70 fs/splice.c:1103
do_splice_direct_actor fs/splice.c:1202 [inline]
do_splice_direct+0x195/0x290 fs/splice.c:1228
do_sendfile+0x535/0x7d0 fs/read_write.c:1372
__do_sys_sendfile64 fs/read_write.c:1433 [inline]
__se_sys_sendfile64+0x144/0x1a0 fs/read_write.c:1419
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&ocfs2_file_ip_alloc_sem_key){++++}-{4:4}:
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
down_write+0x96/0x200 kernel/locking/rwsem.c:1590
ocfs2_expand_inline_dir fs/ocfs2/dir.c:2846 [inline]
ocfs2_extend_dir+0x69a/0x4a60 fs/ocfs2/dir.c:3227
ocfs2_prepare_dir_for_insert+0x34b0/0x5360 fs/ocfs2/dir.c:4345
__ocfs2_prepare_orphan_dir+0x144/0x310 fs/ocfs2/namei.c:2180
ocfs2_prepare_orphan_dir+0xf0/0x420 fs/ocfs2/namei.c:2225
ocfs2_unlink+0xba5/0x1bf0 fs/ocfs2/namei.c:963
vfs_unlink+0x272/0x6c0 fs/namei.c:5470
filename_unlinkat+0x3cd/0x610 fs/namei.c:5540
__do_sys_unlink fs/namei.c:5575 [inline]
__se_sys_unlink+0x2e/0x140 fs/namei.c:5572
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]);
lock(&ocfs2_file_ip_alloc_sem_key);
lock(&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]);
lock(&ocfs2_file_ip_alloc_sem_key);

*** DEADLOCK ***

4 locks held by syz-executor/22669:
#0: ffff8880434d4420 (sb_writers#34){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493
#1: ffff88807a2ad100 (&type->i_mutex_dir_key#22/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline]
#1: ffff88807a2ad100 (&type->i_mutex_dir_key#22/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2923 [inline]
#1: ffff88807a2ad100 (&type->i_mutex_dir_key#22/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2934 [inline]
#1: ffff88807a2ad100 (&type->i_mutex_dir_key#22/1){+.+.}-{4:4}, at: filename_unlinkat+0x2a7/0x610 fs/namei.c:5521
#2: ffff888079e23480 (&sb->s_type->i_mutex_key#43){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
#2: ffff888079e23480 (&sb->s_type->i_mutex_key#43){+.+.}-{4:4}, at: vfs_unlink+0xed/0x6c0 fs/namei.c:5456
#3: ffff88807a2ded80 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
#3: ffff88807a2ded80 (&ocfs2_sysfile_lock_key[ORPHAN_DIR_SYSTEM_INODE]){+.+.}-{4:4}, at: ocfs2_lookup_lock_orphan_dir+0xec/0x2e0 fs/ocfs2/namei.c:2132

stack backtrace:
CPU: 1 UID: 0 PID: 22669 Comm: syz-executor Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
<TASK>
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
print_circular_bug+0x2e1/0x300 kernel/locking/lockdep.c:2043
check_noncircular+0x12e/0x150 kernel/locking/lockdep.c:2175
check_prev_add kernel/locking/lockdep.c:3165 [inline]
check_prevs_add kernel/locking/lockdep.c:3284 [inline]
validate_chain kernel/locking/lockdep.c:3908 [inline]
__lock_acquire+0x15a5/0x2cf0 kernel/locking/lockdep.c:5237
lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868
down_write+0x96/0x200 kernel/locking/rwsem.c:1590
ocfs2_expand_inline_dir fs/ocfs2/dir.c:2846 [inline]
ocfs2_extend_dir+0x69a/0x4a60 fs/ocfs2/dir.c:3227
ocfs2_prepare_dir_for_insert+0x34b0/0x5360 fs/ocfs2/dir.c:4345
__ocfs2_prepare_orphan_dir+0x144/0x310 fs/ocfs2/namei.c:2180
ocfs2_prepare_orphan_dir+0xf0/0x420 fs/ocfs2/namei.c:2225
ocfs2_unlink+0xba5/0x1bf0 fs/ocfs2/namei.c:963
vfs_unlink+0x272/0x6c0 fs/namei.c:5470
filename_unlinkat+0x3cd/0x610 fs/namei.c:5540
__do_sys_unlink fs/namei.c:5575 [inline]
__se_sys_unlink+0x2e/0x140 fs/namei.c:5572
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fea5b19b887
Code: 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffcb7171a28 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fea5b19b887
RDX: 00007ffcb7171a50 RSI: 00007ffcb7171ae0 RDI: 00007ffcb7171ae0
RBP: 00007ffcb7171ae0 R08: 00007ffcb7172ae0 R09: 00000000ffffffff
R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffcb7172bd0
R13: 00007fea5b231f90 R14: 00000000001589a0 R15: 00007ffcb7173ca0
</TASK>


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