[v5.15] possible deadlock in ocfs2_remove_btree_range (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 7b232985052f Linux 5.15.199
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1081b65a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=353ae28c40b35af5
dashboard link: https://syzkaller.appspot.com/bug?extid=e4d011b114b4a8e7f37a
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/97a23052e207/disk-7b232985.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e9871fb1bda3/vmlinux-7b232985.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b08e48f5be44/bzImage-7b232985.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+e4d011...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.210/5207 is trying to acquire lock:
ffff88805e9d6d88
(&ocfs2_sysfile_lock_key[args->fi_sysfile_type]
#8){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
#8){+.+.}-{3:3}, at: ocfs2_remove_btree_range+0x674/0x15e0 fs/ocfs2/alloc.c:5742

but task is already holding lock:
ffff88806370cda0 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_truncate_file+0x31e/0x1460 fs/ocfs2/file.c:467

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}:
down_write+0x38/0x60 kernel/locking/rwsem.c:1551
ocfs2_create_local_dquot+0x199/0x1850 fs/ocfs2/quota_local.c:1224
ocfs2_acquire_dquot+0x7ed/0xb10 fs/ocfs2/quota_global.c:871
dqget+0x778/0xeb0 fs/quota/dquot.c:988
__dquot_initialize+0x3c3/0xcd0 fs/quota/dquot.c:1517
ocfs2_get_init_inode+0x144/0x1b0 fs/ocfs2/namei.c:202
ocfs2_mknod+0x8ab/0x2510 fs/ocfs2/namei.c:310
ocfs2_create+0x192/0x420 fs/ocfs2/namei.c:674
lookup_open fs/namei.c:3470 [inline]
open_last_lookups fs/namei.c:3540 [inline]
path_openat+0x11db/0x2fa0 fs/namei.c:3747
do_filp_open+0x1e2/0x410 fs/namei.c:3777
do_sys_openat2+0x150/0x4b0 fs/open.c:1255
do_sys_open fs/open.c:1271 [inline]
__do_sys_openat fs/open.c:1287 [inline]
__se_sys_openat fs/open.c:1282 [inline]
__x64_sys_openat+0x135/0x160 fs/open.c:1282
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

-> #3 (&dquot->dq_lock){+.+.}-{3:3}:
__mutex_lock_common+0x1e3/0x2400 kernel/locking/mutex.c:596
__mutex_lock kernel/locking/mutex.c:729 [inline]
mutex_lock_nested+0x17/0x20 kernel/locking/mutex.c:743
dquot_commit+0x5a/0x410 fs/quota/dquot.c:507
ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6210
mark_dquot_dirty fs/quota/dquot.c:372 [inline]
mark_all_dquot_dirty+0x1e3/0x400 fs/quota/dquot.c:412
__dquot_alloc_space+0x5d0/0xe20 fs/quota/dquot.c:1752
dquot_alloc_space_nodirty include/linux/quotaops.h:297 [inline]
dquot_alloc_space include/linux/quotaops.h:310 [inline]
dquot_alloc_block include/linux/quotaops.h:334 [inline]
ext4_mb_new_blocks+0xf81/0x4980 fs/ext4/mballoc.c:5750
ext4_alloc_branch fs/ext4/indirect.c:340 [inline]
ext4_ind_map_blocks+0xeb2/0x21b0 fs/ext4/indirect.c:635
ext4_map_blocks+0x92c/0x1b30 fs/ext4/inode.c:675
_ext4_get_block+0x1e7/0x540 fs/ext4/inode.c:816
ext4_block_write_begin+0x61b/0x1220 fs/ext4/inode.c:1101
ext4_write_begin+0x6c8/0x15d0 fs/ext4/ext4_jbd2.h:-1
generic_perform_write+0x2b6/0x550 mm/filemap.c:3785
ext4_buffered_write_iter+0x25f/0x3b0 fs/ext4/file.c:268
ext4_file_write_iter+0x74d/0x1700 fs/ext4/file.c:-1
call_write_iter include/linux/fs.h:2173 [inline]
new_sync_write fs/read_write.c:507 [inline]
vfs_write+0x745/0xd60 fs/read_write.c:594
ksys_write+0x152/0x260 fs/read_write.c:647
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

-> #2 (&ei->i_data_sem){++++}-{3:3}:
down_write+0x38/0x60 kernel/locking/rwsem.c:1551
ext4_truncate+0x97f/0x10f0 fs/ext4/inode.c:4251
ext4_setattr+0xffe/0x19e0 fs/ext4/inode.c:5601
notify_change+0xbcd/0xee0 fs/attr.c:505
do_truncate+0x1ac/0x240 fs/open.c:65
do_sys_ftruncate+0x31b/0x3d0 fs/open.c:193
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

-> #1 (jbd2_handle){++++}-{0:0}:
jbd2_journal_lock_updates+0xa4/0x390 fs/jbd2/transaction.c:881
__ocfs2_flush_truncate_log+0x2ba/0x1110 fs/ocfs2/alloc.c:6027
ocfs2_flush_truncate_log+0x4b/0x60 fs/ocfs2/alloc.c:6074
ocfs2_sync_fs+0x119/0x330 fs/ocfs2/super.c:403
sync_filesystem+0x1be/0x220 fs/sync.c:66
generic_shutdown_super+0x6b/0x300 fs/super.c:448
kill_block_super+0x7c/0xe0 fs/super.c:1427
deactivate_locked_super+0x93/0xf0 fs/super.c:335
cleanup_mnt+0x42d/0x4e0 fs/namespace.c:1148
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 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#8){+.+.}-{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+0x2c42/0x7d10 kernel/locking/lockdep.c:5012
lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
down_write+0x38/0x60 kernel/locking/rwsem.c:1551
inode_lock include/linux/fs.h:787 [inline]
ocfs2_remove_btree_range+0x674/0x15e0 fs/ocfs2/alloc.c:5742
ocfs2_commit_truncate+0xb68/0x1d50 fs/ocfs2/alloc.c:7346
ocfs2_truncate_file+0xd05/0x1460 fs/ocfs2/file.c:505
ocfs2_setattr+0x14dd/0x1ad0 fs/ocfs2/file.c:1215
notify_change+0xbcd/0xee0 fs/attr.c:505
do_truncate+0x1ac/0x240 fs/open.c:65
do_sys_ftruncate+0x31b/0x3d0 fs/open.c:193
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:

Chain exists of:
&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#8 --> &dquot->dq_lock --> &ocfs2_quota_ip_alloc_sem_key

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&ocfs2_quota_ip_alloc_sem_key);
lock(&dquot->dq_lock);
lock(&ocfs2_quota_ip_alloc_sem_key);
lock(&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#8);

*** DEADLOCK ***

3 locks held by syz.0.210/5207:
#0: ffff88807a438460 (sb_writers#13){.+.+}-{0:0}, at: do_sys_ftruncate+0x284/0x3d0 fs/open.c:190
#1: ffff88806370d108 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
#1: ffff88806370d108 (&sb->s_type->i_mutex_key#21){+.+.}-{3:3}, at: do_truncate+0x198/0x240 fs/open.c:63
#2: ffff88806370cda0 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_truncate_file+0x31e/0x1460 fs/ocfs2/file.c:467

stack backtrace:
CPU: 0 PID: 5207 Comm: syz.0.210 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Call Trace:
<TASK>
dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
check_noncircular+0x296/0x330 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+0x2c42/0x7d10 kernel/locking/lockdep.c:5012
lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623
down_write+0x38/0x60 kernel/locking/rwsem.c:1551
inode_lock include/linux/fs.h:787 [inline]
ocfs2_remove_btree_range+0x674/0x15e0 fs/ocfs2/alloc.c:5742
ocfs2_commit_truncate+0xb68/0x1d50 fs/ocfs2/alloc.c:7346
ocfs2_truncate_file+0xd05/0x1460 fs/ocfs2/file.c:505
ocfs2_setattr+0x14dd/0x1ad0 fs/ocfs2/file.c:1215
notify_change+0xbcd/0xee0 fs/attr.c:505
do_truncate+0x1ac/0x240 fs/open.c:65
do_sys_ftruncate+0x31b/0x3d0 fs/open.c:193
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: 0033:0x7f15f815eeb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f15f63ba028 EFLAGS: 00000246 ORIG_RAX: 000000000000004d
RAX: ffffffffffffffda RBX: 00007f15f83d9fa0 RCX: 00007f15f815eeb9
RDX: 0000000000000000 RSI: 0000000000000005 RDI: 0000000000000006
RBP: 00007f15f81ccc1f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f15f83da038 R14: 00007f15f83d9fa0 R15: 00007ffc824713a8
</TASK>


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