[v6.1] possible deadlock in hfsplus_file_extend (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 8e6e2188d949 Linux 6.1.157
git tree: linux-6.1.y
console output: https://syzkaller.appspot.com/x/log.txt?x=12a93a14580000
kernel config: https://syzkaller.appspot.com/x/.config?x=7eb38bd5021fec61
dashboard link: https://syzkaller.appspot.com/bug?extid=5a4f7e1f7b813d0f3bff
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/dcc01324de1b/disk-8e6e2188.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a93dd5469c70/vmlinux-8e6e2188.xz
kernel image: https://storage.googleapis.com/syzbot-assets/04635e384401/bzImage-8e6e2188.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5a4f7e...@syzkaller.appspotmail.com

loop1: detected capacity change from 0 to 1024
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.1.1950/11094 is trying to acquire lock:
ffff88801db7e648 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x1b3/0x1950 fs/hfsplus/extents.c:455

but task is already holding lock:
ffff88805ce1e0b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&tree->tree_lock/1){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
hfsplus_ext_write_extent_locked fs/hfsplus/extents.c:136 [inline]
hfsplus_ext_write_extent+0x148/0x200 fs/hfsplus/extents.c:150
hfsplus_write_inode+0x1e/0x5b0 fs/hfsplus/super.c:154
write_inode fs/fs-writeback.c:1470 [inline]
__writeback_single_inode+0x75b/0x1160 fs/fs-writeback.c:1687
writeback_single_inode+0x221/0x8b0 fs/fs-writeback.c:1743
sync_inode_metadata+0xb6/0x110 fs/fs-writeback.c:2800
hfsplus_file_fsync+0x101/0x500 fs/hfsplus/inode.c:321
generic_write_sync include/linux/fs.h:2962 [inline]
generic_file_write_iter+0x25d/0x2e0 mm/filemap.c:4010
do_iter_readv_writev fs/read_write.c:-1 [inline]
do_iter_write+0x62d/0xaf0 fs/read_write.c:861
vfs_writev fs/read_write.c:934 [inline]
do_pwritev+0x201/0x340 fs/read_write.c:1031
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}:
check_prev_add kernel/locking/lockdep.c:3090 [inline]
check_prevs_add kernel/locking/lockdep.c:3209 [inline]
validate_chain kernel/locking/lockdep.c:3825 [inline]
__lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
hfsplus_file_extend+0x1b3/0x1950 fs/hfsplus/extents.c:455
hfsplus_bmap_reserve+0x11e/0x4f0 fs/hfsplus/btree.c:358
__hfsplus_ext_write_extent+0x28d/0x5b0 fs/hfsplus/extents.c:104
__hfsplus_ext_cache_extent+0x89/0xe20 fs/hfsplus/extents.c:186
hfsplus_file_truncate+0x455/0xb30 fs/hfsplus/extents.c:597
hfsplus_setattr+0x1c0/0x280 fs/hfsplus/inode.c:269
notify_change+0xc74/0xf40 fs/attr.c:499
do_truncate+0x197/0x220 fs/open.c:65
vfs_truncate+0x262/0x2f0 fs/open.c:111
do_sys_truncate+0xdc/0x190 fs/open.c:134
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&tree->tree_lock/1);
lock(&HFSPLUS_I(inode)->extents_lock);
lock(&tree->tree_lock/1);
lock(&HFSPLUS_I(inode)->extents_lock);

*** DEADLOCK ***

4 locks held by syz.1.1950/11094:
#0: ffff88805db14460 (sb_writers#22){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402
#1: ffff88801db789c0 (&sb->s_type->i_mutex_key#30){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
#1: ffff88801db789c0 (&sb->s_type->i_mutex_key#30){+.+.}-{3:3}, at: do_truncate+0x183/0x220 fs/open.c:63
#2: ffff88801db787c8 (&hip->extents_lock){+.+.}-{3:3}, at: hfsplus_file_truncate+0x28f/0xb30 fs/hfsplus/extents.c:574
#3: ffff88805ce1e0b0 (&tree->tree_lock/1){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28

stack backtrace:
CPU: 0 PID: 11094 Comm: syz.1.1950 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
<TASK>
dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2170
check_prev_add kernel/locking/lockdep.c:3090 [inline]
check_prevs_add kernel/locking/lockdep.c:3209 [inline]
validate_chain kernel/locking/lockdep.c:3825 [inline]
__lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
hfsplus_file_extend+0x1b3/0x1950 fs/hfsplus/extents.c:455
hfsplus_bmap_reserve+0x11e/0x4f0 fs/hfsplus/btree.c:358
__hfsplus_ext_write_extent+0x28d/0x5b0 fs/hfsplus/extents.c:104
__hfsplus_ext_cache_extent+0x89/0xe20 fs/hfsplus/extents.c:186
hfsplus_file_truncate+0x455/0xb30 fs/hfsplus/extents.c:597
hfsplus_setattr+0x1c0/0x280 fs/hfsplus/inode.c:269
notify_change+0xc74/0xf40 fs/attr.c:499
do_truncate+0x197/0x220 fs/open.c:65
vfs_truncate+0x262/0x2f0 fs/open.c:111
do_sys_truncate+0xdc/0x190 fs/open.c:134
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f3a7e98efc9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f3a7f857038 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007f3a7ebe5fa0 RCX: 00007f3a7e98efc9
RDX: 0000000000000000 RSI: 000000000000fbb0 RDI: 0000200000000000
RBP: 00007f3a7ea11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3a7ebe6038 R14: 00007f3a7ebe5fa0 R15: 00007ffee3b29588
</TASK>


---
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 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

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: ac56c046adf4 Linux 5.15.195
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1300cd42580000
kernel config: https://syzkaller.appspot.com/x/.config?x=e1bb6d24ef2164eb
dashboard link: https://syzkaller.appspot.com/bug?extid=0ce64e932d4ade47c60d

compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:

disk image: https://storage.googleapis.com/syzbot-assets/c11ec9487150/disk-ac56c046.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f1130a72d3a0/vmlinux-ac56c046.xz
kernel image: https://storage.googleapis.com/syzbot-assets/7608cb6a3be5/bzImage-ac56c046.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:

Reported-by: syzbot+0ce64e...@syzkaller.appspotmail.com

loop4: detected capacity change from 0 to 1024

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------

syz.4.172/4861 is trying to acquire lock:
ffff888076963048 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}, at: hfsplus_file_extend+0x1b3/0x1950 fs/hfsplus/extents.c:455

but task is already holding lock:

ffff88802a2860b0 (&tree->tree_lock#2/1){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&tree->tree_lock#2/1){+.+.}-{3:3}:
__mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28
hfsplus_file_truncate+0x38c/0xb40 fs/hfsplus/extents.c:580
hfsplus_delete_inode fs/hfsplus/inode.c:-1 [inline]
hfsplus_file_release+0x2ff/0x3d0 fs/hfsplus/inode.c:240
__fput+0x234/0x930 fs/file_table.c:311
task_work_run+0x125/0x1a0 kernel/task_work.c:188
tracehook_notify_resume include/linux/tracehook.h:189 [inline]
exit_to_user_mode_loop+0x10f/0x130 kernel/entry/common.c:181
exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:214
__syscall_exit_to_user_mode_work kernel/entry/common.c:296 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:307
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #0 (&HFSPLUS_I(inode)->extents_lock){+.+.}-{3:3}:

check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3788 [inline]
__lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
__mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
hfsplus_file_extend+0x1b3/0x1950 fs/hfsplus/extents.c:455
hfsplus_bmap_reserve+0x11e/0x4f0 fs/hfsplus/btree.c:357

__hfsplus_ext_write_extent+0x28d/0x5b0 fs/hfsplus/extents.c:104
__hfsplus_ext_cache_extent+0x89/0xe20 fs/hfsplus/extents.c:186

hfsplus_file_truncate+0x467/0xb40 fs/hfsplus/extents.c:597
hfsplus_setattr+0x1c0/0x280 fs/hfsplus/inode.c:267
notify_change+0xbcd/0xee0 fs/attr.c:505

do_truncate+0x197/0x220 fs/open.c:65
vfs_truncate+0x262/0x2f0 fs/open.c:111
do_sys_truncate+0xdc/0x190 fs/open.c:134

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----

lock(&tree->tree_lock#2/1);
lock(&HFSPLUS_I(inode)->extents_lock);
lock(&tree->tree_lock#2/1);

lock(&HFSPLUS_I(inode)->extents_lock);

*** DEADLOCK ***

4 locks held by syz.4.172/4861:
#0: ffff888028532460 (sb_writers#25){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386
#1: ffff888076965400 (&sb->s_type->i_mutex_key#30){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
#1: ffff888076965400 (&sb->s_type->i_mutex_key#30){+.+.}-{3:3}, at: do_truncate+0x183/0x220 fs/open.c:63
#2: ffff888076965208 (&hip->extents_lock){+.+.}-{3:3}, at: hfsplus_file_truncate+0x2a0/0xb40 fs/hfsplus/extents.c:574
#3: ffff88802a2860b0 (&tree->tree_lock#2/1){+.+.}-{3:3}, at: hfsplus_find_init+0x150/0x1c0 fs/hfsplus/bfind.c:28

stack backtrace:
CPU: 0 PID: 4861 Comm: syz.4.172 Not tainted syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
<TASK>

dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2133
check_prev_add kernel/locking/lockdep.c:3053 [inline]
check_prevs_add kernel/locking/lockdep.c:3172 [inline]
validate_chain kernel/locking/lockdep.c:3788 [inline]
__lock_acquire+0x2c33/0x7c60 kernel/locking/lockdep.c:5012
lock_acquire+0x197/0x3f0 kernel/locking/lockdep.c:5623
__mutex_lock_common+0x1eb/0x2390 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
hfsplus_file_extend+0x1b3/0x1950 fs/hfsplus/extents.c:455
hfsplus_bmap_reserve+0x11e/0x4f0 fs/hfsplus/btree.c:357

__hfsplus_ext_write_extent+0x28d/0x5b0 fs/hfsplus/extents.c:104
__hfsplus_ext_cache_extent+0x89/0xe20 fs/hfsplus/extents.c:186

hfsplus_file_truncate+0x467/0xb40 fs/hfsplus/extents.c:597
hfsplus_setattr+0x1c0/0x280 fs/hfsplus/inode.c:267
notify_change+0xbcd/0xee0 fs/attr.c:505

do_truncate+0x197/0x220 fs/open.c:65
vfs_truncate+0x262/0x2f0 fs/open.c:111
do_sys_truncate+0xdc/0x190 fs/open.c:134

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fec6fdfefc9

Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48

RSP: 002b:00007fec6e066038 EFLAGS: 00000246 ORIG_RAX: 000000000000004c
RAX: ffffffffffffffda RBX: 00007fec70055fa0 RCX: 00007fec6fdfefc9

RDX: 0000000000000000 RSI: 000000000000fbb0 RDI: 0000200000000000

RBP: 00007fec6fe81f91 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 00007fec70056038 R14: 00007fec70055fa0 R15: 00007ffdde9133c8