[v5.15] possible deadlock in ocfs2_remove_btree_range (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 674f684f7c61 Linux 5.15.212
git tree: linux-5.15.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17c20aea580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f161cbc9aef65db0
dashboard link: https://syzkaller.appspot.com/bug?extid=5ef4e438a0104b474f2c
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f55be2937b89/disk-674f684f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a19fb0ffc049/vmlinux-674f684f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/365d4529a007/bzImage-674f684f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5ef4e4...@syzkaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.9.1913/11769 is trying to acquire lock:
ffff8880524a6d88 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
ffff8880524a6d88 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{3:3}, at: ocfs2_remove_btree_range+0x64f/0x15e0 fs/ocfs2/alloc.c:5742

but task is already holding lock:
ffff8880524a5be0 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_truncate_file+0x335/0x1540 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+0x199/0x18d0 fs/ocfs2/quota_local.c:1224
ocfs2_acquire_dquot+0x822/0xb30 fs/ocfs2/quota_global.c:871
dqget+0x713/0xbb0 fs/quota/dquot.c:1010
dquot_set_dqblk+0x27/0xfb0 fs/quota/dquot.c:2848
quota_setquota+0x4d6/0x590 fs/quota/quota.c:309
__do_sys_quotactl fs/quota/quota.c:959 [inline]
__se_sys_quotactl+0x28b/0x6f0 fs/quota/quota.c:915
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+0x1e5/0x2400 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:532
ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6212
mark_dquot_dirty fs/quota/dquot.c:397 [inline]
mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:437
__dquot_alloc_space+0x5cb/0xe10 fs/quota/dquot.c:1774
dquot_alloc_space_nodirty include/linux/quotaops.h:290 [inline]
dquot_alloc_space include/linux/quotaops.h:303 [inline]
dquot_alloc_block include/linux/quotaops.h:327 [inline]
ext4_mb_new_blocks+0xf80/0x47c0 fs/ext4/mballoc.c:5750
ext4_ext_map_blocks+0x17d1/0x63d0 fs/ext4/extents.c:4372
ext4_map_blocks+0x97f/0x1a50 fs/ext4/inode.c:675
ext4_getblk+0x176/0x670 fs/ext4/inode.c:872
ext4_bread+0x26/0x180 fs/ext4/inode.c:925
ext4_append+0x2bb/0x560 fs/ext4/namei.c:83
ext4_init_new_dir+0x2a7/0x910 fs/ext4/namei.c:3030
ext4_mkdir+0x4c3/0xc90 fs/ext4/namei.c:3076
vfs_mkdir+0x386/0x570 fs/namei.c:4073
do_mkdirat+0x1dd/0x5c0 fs/namei.c:4098
__do_sys_mkdirat fs/namei.c:4113 [inline]
__se_sys_mkdirat fs/namei.c:4111 [inline]
__x64_sys_mkdirat+0x85/0x90 fs/namei.c:4111
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_read+0x44/0x2e0 kernel/locking/rwsem.c:1498
ext4_map_blocks+0x350/0x1a50 fs/ext4/inode.c:600
ext4_append+0x22d/0x560 fs/ext4/namei.c:75
ext4_init_new_dir+0x2a7/0x910 fs/ext4/namei.c:3030
ext4_mkdir+0x4c3/0xc90 fs/ext4/namei.c:3076
vfs_mkdir+0x386/0x570 fs/namei.c:4073
do_mkdirat+0x1dd/0x5c0 fs/namei.c:4098
__do_sys_mkdir fs/namei.c:4118 [inline]
__se_sys_mkdir fs/namei.c:4116 [inline]
__x64_sys_mkdir+0x6a/0x80 fs/namei.c:4116
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+0x2b4/0x1110 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
ocfs2_remount+0x123/0xb30 fs/ocfs2/super.c:612
reconfigure_super+0x224/0x8d0 fs/super.c:938
do_remount fs/namespace.c:2697 [inline]
path_mount+0xc5a/0xfe0 fs/namespace.c:3356
do_mount fs/namespace.c:3377 [inline]
__do_sys_mount fs/namespace.c:3585 [inline]
__se_sys_mount+0x2e3/0x3d0 fs/namespace.c:3562
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

-> #0 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5){+.+.}-{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+0x2c66/0x7b50 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+0x64f/0x15e0 fs/ocfs2/alloc.c:5742
ocfs2_commit_truncate+0xb62/0x1d30 fs/ocfs2/alloc.c:7346
ocfs2_truncate_file+0xd89/0x1540 fs/ocfs2/file.c:505
ocfs2_setattr+0x1545/0x1b40 fs/ocfs2/file.c:1215
notify_change+0xbc6/0xee0 fs/attr.c:505
do_truncate+0x1ac/0x240 fs/open.c:65
handle_truncate fs/namei.c:3273 [inline]
do_open fs/namei.c:3620 [inline]
path_openat+0x293b/0x2fb0 fs/namei.c:3750
do_filp_open+0x1df/0x400 fs/namei.c:3777
do_sys_openat2+0x14b/0x500 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

other info that might help us debug this:

Chain exists of:
&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#5 --> &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]#5);

*** DEADLOCK ***

3 locks held by syz.9.1913/11769:
#0: ffff888062ffa460 (sb_writers#21){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386
#1: ffff8880524a5f48 (&sb->s_type->i_mutex_key#30){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline]
#1: ffff8880524a5f48 (&sb->s_type->i_mutex_key#30){+.+.}-{3:3}, at: do_truncate+0x198/0x240 fs/open.c:63
#2: ffff8880524a5be0 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_truncate_file+0x335/0x1540 fs/ocfs2/file.c:467

stack backtrace:
CPU: 0 PID: 11769 Comm: syz.9.1913 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
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+0x2c66/0x7b50 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+0x64f/0x15e0 fs/ocfs2/alloc.c:5742
ocfs2_commit_truncate+0xb62/0x1d30 fs/ocfs2/alloc.c:7346
ocfs2_truncate_file+0xd89/0x1540 fs/ocfs2/file.c:505
ocfs2_setattr+0x1545/0x1b40 fs/ocfs2/file.c:1215
notify_change+0xbc6/0xee0 fs/attr.c:505
do_truncate+0x1ac/0x240 fs/open.c:65
handle_truncate fs/namei.c:3273 [inline]
do_open fs/namei.c:3620 [inline]
path_openat+0x293b/0x2fb0 fs/namei.c:3750
do_filp_open+0x1df/0x400 fs/namei.c:3777
do_sys_openat2+0x14b/0x500 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
RIP: 0033:0x7faa38666e99
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:00007faa3689e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007faa388ef090 RCX: 00007faa38666e99
RDX: 000000000000275a RSI: 0000200000000040 RDI: ffffffffffffff9c
RBP: 00007faa386fceaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007faa388ef128 R14: 00007faa388ef090 R15: 00007ffecc2c4968
</TASK>


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