[v6.6] possible deadlock in ocfs2_acquire_dquot

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cc1a1c5b404a Linux 6.6.103
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=150e8e62580000
kernel config: https://syzkaller.appspot.com/x/.config?x=412020841cf033b0
dashboard link: https://syzkaller.appspot.com/bug?extid=c65952575aa91f3e8533
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/46c06862a545/disk-cc1a1c5b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/38ddabb6fc8b/vmlinux-cc1a1c5b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b130b7d031b5/bzImage-cc1a1c5b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c65952...@syzkaller.appspotmail.com

JBD2: Ignoring recovery information on journal
ocfs2: Mounting device (7,3) on (node local, slot 0) with ordered data mode.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.3.9925/28065 is trying to acquire lock:
ffff8880249b4608 (sb_internal#3){.+.+}-{0:0}, at: ocfs2_acquire_dquot+0x67b/0xaf0 fs/ocfs2/quota_global.c:848

but task is already holding lock:
ffff88805bddbf60 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_lock_global_qf+0x1e9/0x270 fs/ocfs2/quota_global.c:314

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #6 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}:
down_write+0x97/0x1f0 kernel/locking/rwsem.c:1573
ocfs2_lock_global_qf+0x1e9/0x270 fs/ocfs2/quota_global.c:314
ocfs2_acquire_dquot+0x2a1/0xaf0 fs/ocfs2/quota_global.c:816
dqget+0x77c/0xeb0 fs/quota/dquot.c:988
dquot_set_dqblk+0x2b/0xf90 fs/quota/dquot.c:2831
quota_setquota+0x4b0/0x530 fs/quota/quota.c:310
__do_sys_quotactl fs/quota/quota.c:961 [inline]
__se_sys_quotactl+0x27b/0x950 fs/quota/quota.c:917
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #5 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7){+.+.}-{3:3}:
down_write+0x97/0x1f0 kernel/locking/rwsem.c:1573
inode_lock include/linux/fs.h:804 [inline]
ocfs2_lock_global_qf+0x1cb/0x270 fs/ocfs2/quota_global.c:313
ocfs2_acquire_dquot+0x2a1/0xaf0 fs/ocfs2/quota_global.c:816
dqget+0x77c/0xeb0 fs/quota/dquot.c:988
dquot_set_dqblk+0x2b/0xf90 fs/quota/dquot.c:2831
quota_setquota+0x4b0/0x530 fs/quota/quota.c:310
__do_sys_quotactl fs/quota/quota.c:961 [inline]
__se_sys_quotactl+0x27b/0x950 fs/quota/quota.c:917
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #4 (&dquot->dq_lock){+.+.}-{3:3}:
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x129/0xcc0 kernel/locking/mutex.c:747
wait_on_dquot fs/quota/dquot.c:356 [inline]
dqget+0x6fc/0xeb0 fs/quota/dquot.c:983
dquot_transfer+0x2f9/0x6d0 fs/quota/dquot.c:2149
ext4_setattr+0x87d/0x1c90 fs/ext4/inode.c:5477
notify_change+0xb0d/0xe10 fs/attr.c:499
chown_common+0x3f9/0x5a0 fs/open.c:783
do_fchownat+0x168/0x270 fs/open.c:814
__do_sys_lchown fs/open.c:839 [inline]
__se_sys_lchown fs/open.c:837 [inline]
__x64_sys_lchown+0x85/0x90 fs/open.c:837
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #3 (&ei->xattr_sem){++++}-{3:3}:
down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520
ext4_setattr+0x86b/0x1c90 fs/ext4/inode.c:5476
notify_change+0xb0d/0xe10 fs/attr.c:499
chown_common+0x3f9/0x5a0 fs/open.c:783
do_fchownat+0x168/0x270 fs/open.c:814
__do_sys_chown fs/open.c:834 [inline]
__se_sys_chown fs/open.c:832 [inline]
__x64_sys_chown+0x82/0x90 fs/open.c:832
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #2 (jbd2_handle){++++}-{0:0}:
start_this_handle+0x1e9d/0x20c0 fs/jbd2/transaction.c:448
jbd2__journal_start+0x2bb/0x5b0 fs/jbd2/transaction.c:505
jbd2_journal_start+0x2a/0x40 fs/jbd2/transaction.c:544
ocfs2_start_trans+0x376/0x6c0 fs/ocfs2/journal.c:374
ocfs2_modify_bh+0xe9/0x470 fs/ocfs2/quota_local.c:101
ocfs2_local_read_info+0x13fd/0x1770 fs/ocfs2/quota_local.c:764
dquot_load_quota_sb+0x757/0xb80 fs/quota/dquot.c:2468
dquot_load_quota_inode+0x2dc/0x5d0 fs/quota/dquot.c:2505
ocfs2_enable_quotas+0x1c7/0x440 fs/ocfs2/super.c:926
ocfs2_fill_super+0x3f6d/0x4d90 fs/ocfs2/super.c:1141
mount_bdev+0x22b/0x2d0 fs/super.c:1643
legacy_get_tree+0xea/0x180 fs/fs_context.c:662
vfs_get_tree+0x8c/0x280 fs/super.c:1764
do_new_mount+0x24b/0xa40 fs/namespace.c:3377
do_mount fs/namespace.c:3717 [inline]
__do_sys_mount fs/namespace.c:3926 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3903
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #1 (&journal->j_trans_barrier){.+.+}-{3:3}:
down_read+0x46/0x2e0 kernel/locking/rwsem.c:1520
ocfs2_start_trans+0x36a/0x6c0 fs/ocfs2/journal.c:372
ocfs2_modify_bh+0xe9/0x470 fs/ocfs2/quota_local.c:101
ocfs2_local_read_info+0x13fd/0x1770 fs/ocfs2/quota_local.c:764
dquot_load_quota_sb+0x757/0xb80 fs/quota/dquot.c:2468
dquot_load_quota_inode+0x2dc/0x5d0 fs/quota/dquot.c:2505
ocfs2_enable_quotas+0x1c7/0x440 fs/ocfs2/super.c:926
ocfs2_fill_super+0x3f6d/0x4d90 fs/ocfs2/super.c:1141
mount_bdev+0x22b/0x2d0 fs/super.c:1643
legacy_get_tree+0xea/0x180 fs/fs_context.c:662
vfs_get_tree+0x8c/0x280 fs/super.c:1764
do_new_mount+0x24b/0xa40 fs/namespace.c:3377
do_mount fs/namespace.c:3717 [inline]
__do_sys_mount fs/namespace.c:3926 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3903
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #0 (sb_internal#3){.+.+}-{0:0}:
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1633 [inline]
sb_start_intwrite include/linux/fs.h:1755 [inline]
ocfs2_start_trans+0x26b/0x6c0 fs/ocfs2/journal.c:370
ocfs2_acquire_dquot+0x67b/0xaf0 fs/ocfs2/quota_global.c:848
dqget+0x77c/0xeb0 fs/quota/dquot.c:988
dquot_set_dqblk+0x2b/0xf90 fs/quota/dquot.c:2831
quota_setquota+0x4b0/0x530 fs/quota/quota.c:310
__do_sys_quotactl fs/quota/quota.c:961 [inline]
__se_sys_quotactl+0x27b/0x950 fs/quota/quota.c:917
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2

other info that might help us debug this:

Chain exists of:
sb_internal#3 --> &ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7 --> &ocfs2_quota_ip_alloc_sem_key

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&ocfs2_quota_ip_alloc_sem_key);
lock(&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7);
lock(&ocfs2_quota_ip_alloc_sem_key);
rlock(sb_internal#3);

*** DEADLOCK ***

4 locks held by syz.3.9925/28065:
#0: ffff8880249b40e0 (&type->s_umount_key#100){++++}-{3:3}, at: __super_lock fs/super.c:58 [inline]
#0: ffff8880249b40e0 (&type->s_umount_key#100){++++}-{3:3}, at: super_lock+0x167/0x360 fs/super.c:117
#1: ffff88805250a0a8 (&dquot->dq_lock){+.+.}-{3:3}, at: ocfs2_acquire_dquot+0x294/0xaf0 fs/ocfs2/quota_global.c:811
#2: ffff88805bddc2d8 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7){+.+.}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
#2: ffff88805bddc2d8 (&ocfs2_sysfile_lock_key[args->fi_sysfile_type]#7){+.+.}-{3:3}, at: ocfs2_lock_global_qf+0x1cb/0x270 fs/ocfs2/quota_global.c:313
#3: ffff88805bddbf60 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}, at: ocfs2_lock_global_qf+0x1e9/0x270 fs/ocfs2/quota_global.c:314

stack backtrace:
CPU: 0 PID: 28065 Comm: syz.3.9925 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
<TASK>
dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
check_noncircular+0x2bd/0x3c0 kernel/locking/lockdep.c:2187
check_prev_add kernel/locking/lockdep.c:3134 [inline]
check_prevs_add kernel/locking/lockdep.c:3253 [inline]
validate_chain kernel/locking/lockdep.c:3869 [inline]
__lock_acquire+0x2ddb/0x7c80 kernel/locking/lockdep.c:5137
lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
percpu_down_read include/linux/percpu-rwsem.h:51 [inline]
__sb_start_write include/linux/fs.h:1633 [inline]
sb_start_intwrite include/linux/fs.h:1755 [inline]
ocfs2_start_trans+0x26b/0x6c0 fs/ocfs2/journal.c:370
ocfs2_acquire_dquot+0x67b/0xaf0 fs/ocfs2/quota_global.c:848
dqget+0x77c/0xeb0 fs/quota/dquot.c:988
dquot_set_dqblk+0x2b/0xf90 fs/quota/dquot.c:2831
quota_setquota+0x4b0/0x530 fs/quota/quota.c:310
__do_sys_quotactl fs/quota/quota.c:961 [inline]
__se_sys_quotactl+0x27b/0x950 fs/quota/quota.c:917
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fdab3f8ebe9
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:00007fdab4d6f038 EFLAGS: 00000246 ORIG_RAX: 00000000000000b3
RAX: ffffffffffffffda RBX: 00007fdab41c5fa0 RCX: 00007fdab3f8ebe9
RDX: 0000000000000000 RSI: 00002000000000c0 RDI: ffffffff80000800
RBP: 00007fdab4011e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000200000000040 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fdab41c6038 R14: 00007fdab41c5fa0 R15: 00007ffdb11ac3d8
</TASK>


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