syzbot

EXT4-fs (loop1): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.
ext4 filesystem being mounted at /3552/file0 supports timestamps until 2038-01-19 (0x7fffffff)
======================================================
WARNING: possible circular locking dependency detected
6.6.101-syzkaller #0 Not tainted
------------------------------------------------------
syz.1.14624/6058 is trying to acquire lock:
ffff88805888d768 (&dquot->dq_lock){+.+.}-{3:3}, at: wait_on_dquot fs/quota/dquot.c:356 [inline]
ffff88805888d768 (&dquot->dq_lock){+.+.}-{3:3}, at: dqget+0x6fc/0xeb0 fs/quota/dquot.c:983

but task is already holding lock:
ffff8880776150c8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_setattr+0x86b/0x1c90 fs/ext4/inode.c:5476

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #5 (&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

-> #4 (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:3371
       do_mount fs/namespace.c:3711 [inline]
       __do_sys_mount fs/namespace.c:3920 [inline]
       __se_sys_mount+0x2da/0x3c0 fs/namespace.c:3897
       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 (&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:3371
       do_mount fs/namespace.c:3711 [inline]
       __do_sys_mount fs/namespace.c:3920 [inline]
       __se_sys_mount+0x2da/0x3c0 fs/namespace.c:3897
       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 (sb_internal#2){.+.+}-{0:0}:
       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

-> #1 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}:
       down_write+0x97/0x1f0 kernel/locking/rwsem.c:1573
       ocfs2_create_local_dquot+0x1a4/0x1790 fs/ocfs2/quota_local.c:1224
       ocfs2_acquire_dquot+0x7cf/0xaf0 fs/ocfs2/quota_global.c:871
       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

-> #0 (&dquot->dq_lock){+.+.}-{3:3}:
       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
       __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_fchownat fs/open.c:829 [inline]
       __se_sys_fchownat fs/open.c:826 [inline]
       __x64_sys_fchownat+0xb5/0xd0 fs/open.c:826
       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:
  &dquot->dq_lock --> jbd2_handle --> &ei->xattr_sem

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(&ei->xattr_sem);
                               lock(jbd2_handle);
                               lock(&ei->xattr_sem);
  lock(&dquot->dq_lock);

 *** DEADLOCK ***

3 locks held by syz.1.14624/6058:
 #0: ffff888025ede418 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:403
 #1: ffff888077615410 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: inode_lock include/linux/fs.h:804 [inline]
 #1: ffff888077615410 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: chown_common+0x313/0x5a0 fs/open.c:773
 #2: ffff8880776150c8 (&ei->xattr_sem){++++}-{3:3}, at: ext4_setattr+0x86b/0x1c90 fs/ext4/inode.c:5476

stack backtrace:
CPU: 1 PID: 6058 Comm: syz.1.14624 Not tainted 6.6.101-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
 __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_fchownat fs/open.c:829 [inline]
 __se_sys_fchownat fs/open.c:826 [inline]
 __x64_sys_fchownat+0xb5/0xd0 fs/open.c:826
 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: 0033:0x7f36cd78eb69
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:00007f36ce5d4038 EFLAGS: 00000246 ORIG_RAX: 0000000000000104
RAX: ffffffffffffffda RBX: 00007f36cd9b5fa0 RCX: 00007f36cd78eb69
RDX: 000000000000ee01 RSI: 0000200000000100 RDI: ffffffffffffff9c
RBP: 00007f36cd811df1 R08: 0000000000001000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f36cd9b5fa0 R15: 00007fffd37c64c8
 </TASK>