syzbot

loop0: detected capacity change from 0 to 512
EXT4-fs (loop0): orphan cleanup on readonly fs
======================================================
WARNING: possible circular locking dependency detected
6.3.0-rc4-syzkaller-00051-g8bb95a1662f8 #0 Not tainted
------------------------------------------------------
syz-executor202/5200 is trying to acquire lock:
ffff8880746f8ea8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5b/0x520 fs/quota/dquot.c:479

but task is already holding lock:
ffff8880770e52c8 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_truncate+0x981/0x1150 fs/ext4/inode.c:4337

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&ei->i_data_sem/2){++++}-{3:3}:
       lock_acquire+0x1e1/0x520 kernel/locking/lockdep.c:5669
       down_read+0x3d/0x50 kernel/locking/rwsem.c:1520
       ext4_map_blocks+0x38e/0x1cf0 fs/ext4/inode.c:574
       ext4_getblk+0x1ef/0x7c0 fs/ext4/inode.c:863
       ext4_bread+0x2e/0x180 fs/ext4/inode.c:919
       ext4_quota_write+0x222/0x580 fs/ext4/super.c:7135
       write_blk fs/quota/quota_tree.c:64 [inline]
       get_free_dqblk+0x336/0x690 fs/quota/quota_tree.c:130
       do_insert_tree+0x265/0x1a60 fs/quota/quota_tree.c:340
       do_insert_tree+0x70f/0x1a60 fs/quota/quota_tree.c:375
       do_insert_tree+0x70f/0x1a60 fs/quota/quota_tree.c:375
       do_insert_tree+0x70f/0x1a60 fs/quota/quota_tree.c:375
       dq_insert_tree fs/quota/quota_tree.c:401 [inline]
       qtree_write_dquot+0x3bd/0x530 fs/quota/quota_tree.c:420
       v2_write_dquot+0x120/0x190 fs/quota/quota_v2.c:358
       dquot_acquire+0x351/0x680 fs/quota/dquot.c:444
       ext4_acquire_dquot+0x2e6/0x400 fs/ext4/super.c:6770
       dqget+0x98f/0xdb0 fs/quota/dquot.c:914
       __dquot_initialize+0x462/0xe20 fs/quota/dquot.c:1492
       ext4_process_orphan+0x57/0x2d0 fs/ext4/orphan.c:329
       ext4_orphan_cleanup+0xb21/0x13c0 fs/ext4/orphan.c:474
       __ext4_fill_super fs/ext4/super.c:5509 [inline]
       ext4_fill_super+0x8239/0x8990 fs/ext4/super.c:5637
       get_tree_bdev+0x402/0x620 fs/super.c:1303
       vfs_get_tree+0x8c/0x270 fs/super.c:1510
       do_new_mount+0x28f/0xae0 fs/namespace.c:3042
       do_mount fs/namespace.c:3385 [inline]
       __do_sys_mount fs/namespace.c:3594 [inline]
       __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3571
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #1 (&s->s_dquot.dqio_sem){++++}-{3:3}:
       lock_acquire+0x1e1/0x520 kernel/locking/lockdep.c:5669
       down_read+0x3d/0x50 kernel/locking/rwsem.c:1520
       v2_read_dquot+0x4e/0x110 fs/quota/quota_v2.c:332
       dquot_acquire+0x18c/0x680 fs/quota/dquot.c:435
       ext4_acquire_dquot+0x2e6/0x400 fs/ext4/super.c:6770
       dqget+0x98f/0xdb0 fs/quota/dquot.c:914
       __dquot_initialize+0x2dd/0xe20 fs/quota/dquot.c:1492
       ext4_process_orphan+0x57/0x2d0 fs/ext4/orphan.c:329
       ext4_orphan_cleanup+0xb21/0x13c0 fs/ext4/orphan.c:474
       __ext4_fill_super fs/ext4/super.c:5509 [inline]
       ext4_fill_super+0x8239/0x8990 fs/ext4/super.c:5637
       get_tree_bdev+0x402/0x620 fs/super.c:1303
       vfs_get_tree+0x8c/0x270 fs/super.c:1510
       do_new_mount+0x28f/0xae0 fs/namespace.c:3042
       do_mount fs/namespace.c:3385 [inline]
       __do_sys_mount fs/namespace.c:3594 [inline]
       __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3571
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

-> #0 (&dquot->dq_lock){+.+.}-{3:3}:
       check_prev_add kernel/locking/lockdep.c:3098 [inline]
       check_prevs_add kernel/locking/lockdep.c:3217 [inline]
       validate_chain+0x166b/0x58e0 kernel/locking/lockdep.c:3832
       __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
       lock_acquire+0x1e1/0x520 kernel/locking/lockdep.c:5669
       __mutex_lock_common+0x1d8/0x2530 kernel/locking/mutex.c:603
       __mutex_lock kernel/locking/mutex.c:747 [inline]
       mutex_lock_nested+0x1b/0x20 kernel/locking/mutex.c:799
       dquot_commit+0x5b/0x520 fs/quota/dquot.c:479
       ext4_write_dquot+0x1f2/0x2c0 fs/ext4/super.c:6754
       mark_dquot_dirty fs/quota/dquot.c:346 [inline]
       mark_all_dquot_dirty fs/quota/dquot.c:384 [inline]
       __dquot_free_space+0x9a4/0xfc0 fs/quota/dquot.c:1907
       dquot_free_space_nodirty include/linux/quotaops.h:379 [inline]
       dquot_free_space include/linux/quotaops.h:384 [inline]
       dquot_free_block include/linux/quotaops.h:395 [inline]
       ext4_mb_clear_bb fs/ext4/mballoc.c:6044 [inline]
       ext4_free_blocks+0x1ea3/0x2dd0 fs/ext4/mballoc.c:6173
       ext4_remove_blocks fs/ext4/extents.c:2545 [inline]
       ext4_ext_rm_leaf fs/ext4/extents.c:2710 [inline]
       ext4_ext_remove_space+0x216e/0x4d90 fs/ext4/extents.c:2958
       ext4_ext_truncate+0x176/0x210 fs/ext4/extents.c:4416
       ext4_truncate+0xa0a/0x1150 fs/ext4/inode.c:4342
       ext4_process_orphan+0x1aa/0x2d0 fs/ext4/orphan.c:339
       ext4_orphan_cleanup+0xb21/0x13c0 fs/ext4/orphan.c:474
       __ext4_fill_super fs/ext4/super.c:5509 [inline]
       ext4_fill_super+0x8239/0x8990 fs/ext4/super.c:5637
       get_tree_bdev+0x402/0x620 fs/super.c:1303
       vfs_get_tree+0x8c/0x270 fs/super.c:1510
       do_new_mount+0x28f/0xae0 fs/namespace.c:3042
       do_mount fs/namespace.c:3385 [inline]
       __do_sys_mount fs/namespace.c:3594 [inline]
       __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3571
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x63/0xcd

other info that might help us debug this:

Chain exists of:
  &dquot->dq_lock --> &s->s_dquot.dqio_sem --> &ei->i_data_sem/2

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&ei->i_data_sem/2);
                               lock(&s->s_dquot.dqio_sem);
                               lock(&ei->i_data_sem/2);
  lock(&dquot->dq_lock);

 *** DEADLOCK ***

4 locks held by syz-executor202/5200:
 #0: ffff88807c1680e0 (&type->s_umount_key#27/1){+.+.}-{3:3}, at: alloc_super+0x217/0x930 fs/super.c:228
 #1: ffff8880770e5440 (&sb->s_type->i_mutex_key#7){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff8880770e5440 (&sb->s_type->i_mutex_key#7){++++}-{3:3}, at: ext4_process_orphan+0x164/0x2d0 fs/ext4/orphan.c:337
 #2: ffff8880770e52c8 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_truncate+0x981/0x1150 fs/ext4/inode.c:4337
 #3: ffffffff8d0697c8 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire+0x5/0x40 include/linux/rcupdate.h:326

stack backtrace:
CPU: 0 PID: 5200 Comm: syz-executor202 Not tainted 6.3.0-rc4-syzkaller-00051-g8bb95a1662f8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x2fe/0x3b0 kernel/locking/lockdep.c:2178
 check_prev_add kernel/locking/lockdep.c:3098 [inline]
 check_prevs_add kernel/locking/lockdep.c:3217 [inline]
 validate_chain+0x166b/0x58e0 kernel/locking/lockdep.c:3832
 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5056
 lock_acquire+0x1e1/0x520 kernel/locking/lockdep.c:5669
 __mutex_lock_common+0x1d8/0x2530 kernel/locking/mutex.c:603
 __mutex_lock kernel/locking/mutex.c:747 [inline]
 mutex_lock_nested+0x1b/0x20 kernel/locking/mutex.c:799
 dquot_commit+0x5b/0x520 fs/quota/dquot.c:479
 ext4_write_dquot+0x1f2/0x2c0 fs/ext4/super.c:6754
 mark_dquot_dirty fs/quota/dquot.c:346 [inline]
 mark_all_dquot_dirty fs/quota/dquot.c:384 [inline]
 __dquot_free_space+0x9a4/0xfc0 fs/quota/dquot.c:1907
 dquot_free_space_nodirty include/linux/quotaops.h:379 [inline]
 dquot_free_space include/linux/quotaops.h:384 [inline]
 dquot_free_block include/linux/quotaops.h:395 [inline]
 ext4_mb_clear_bb fs/ext4/mballoc.c:6044 [inline]
 ext4_free_blocks+0x1ea3/0x2dd0 fs/ext4/mballoc.c:6173
 ext4_remove_blocks fs/ext4/extents.c:2545 [inline]
 ext4_ext_rm_leaf fs/ext4/extents.c:2710 [inline]
 ext4_ext_remove_space+0x216e/0x4d90 fs/ext4/extents.c:2958
 ext4_ext_truncate+0x176/0x210 fs/ext4/extents.c:4416
 ext4_truncate+0xa0a/0x1150 fs/ext4/inode.c:4342
 ext4_process_orphan+0x1aa/0x2d0 fs/ext4/orphan.c:339
 ext4_orphan_cleanup+0xb21/0x13c0 fs/ext4/orphan.c:474
 __ext4_fill_super fs/ext4/super.c:5509 [inline]
 ext4_fill_super+0x8239/0x8990 fs/ext4/super.c:5637
 get_tree_bdev+0x402/0x620 fs/super.c:1303
 vfs_get_tree+0x8c/0x270 fs/super.c:1510
 do_new_mount+0x28f/0xae0 fs/namespace.c:3042
 do_mount fs/namespace.c:3385 [inline]
 __do_sys_mount fs/namespace.c:3594 [inline]
 __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3571
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fa960c40d1a
Code: 48 c7 c2 c0 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 a8 00 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd0bec2ae8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 000055555591f2c0 RCX: 00007fa960c40d1a
RDX: 0000000020000140 RSI: 0000000020000500 RDI: 00007ffd0bec2b30
RBP: 0000000000000000 R08: 00007ffd0bec2b70 R09: 000000000000049f
R10: 0000000000000047 R11: 0000000000000202 R12: 0000000000000004
R13: 00007ffd0bec2b70 R14: 0000000000000003 R15: 00007ffd0bec2b30
 </TASK>
EXT4-fs (loop0): 1 truncate cleaned up