syzbot

EXT4-fs error (device loop0): ext4_do_update_inode:5229: inode #3: comm syz.0.57: corrupted inode contents
EXT4-fs error (device loop0): ext4_dirty_inode:6077: inode #3: comm syz.0.57: mark_inode_dirty error
EXT4-fs error (device loop0): ext4_do_update_inode:5229: inode #3: comm syz.0.57: corrupted inode contents
EXT4-fs error (device loop0): __ext4_ext_dirty:183: inode #3: comm syz.0.57: mark_inode_dirty error
EXT4-fs error (device loop0): ext4_acquire_dquot:6236: comm syz.0.57: Failed to acquire dquot type 0
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.0.57/4400 is trying to acquire lock:
ffff888068b305e8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:532

but task is already holding lock:
ffff888068aca060 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_truncate+0x994/0x1190 fs/ext4/inode.c:4258

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #2 (&ei->i_data_sem/2){++++}-{3:3}:
       down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498
       ext4_map_blocks+0x350/0x1a50 fs/ext4/inode.c:600
       ext4_getblk+0x176/0x670 fs/ext4/inode.c:872
       ext4_bread+0x26/0x180 fs/ext4/inode.c:925
       ext4_quota_write+0x237/0x580 fs/ext4/super.c:6623
       write_blk fs/quota/quota_tree.c:64 [inline]
       get_free_dqblk+0x38a/0x7a0 fs/quota/quota_tree.c:125
       do_insert_tree+0x21b/0x19c0 fs/quota/quota_tree.c:335
       do_insert_tree+0x5c4/0x19c0 fs/quota/quota_tree.c:366
       do_insert_tree+0x5c4/0x19c0 fs/quota/quota_tree.c:366
       do_insert_tree+0x5c4/0x19c0 fs/quota/quota_tree.c:366
       dq_insert_tree fs/quota/quota_tree.c:392 [inline]
       qtree_write_dquot+0x354/0x4a0 fs/quota/quota_tree.c:411
       v2_write_dquot+0x108/0x190 fs/quota/quota_v2.c:358
       dquot_acquire+0x2d5/0x520 fs/quota/dquot.c:497
       ext4_acquire_dquot+0x2e3/0x4a0 fs/ext4/super.c:6232
       dqget+0x713/0xbb0 fs/quota/dquot.c:1010
       __dquot_initialize+0x3a9/0xd00 fs/quota/dquot.c:1539
       ext4_process_orphan+0x4c/0x2e0 fs/ext4/orphan.c:327
       ext4_orphan_cleanup+0xad8/0x1320 fs/ext4/orphan.c:472
       ext4_fill_super+0x8c65/0x93f0 fs/ext4/super.c:5006
       mount_bdev+0x28a/0x3c0 fs/super.c:1400
       legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
       vfs_get_tree+0x88/0x270 fs/super.c:1530
       do_new_mount+0x247/0xa40 fs/namespace.c:3034
       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

-> #1 (&s->s_dquot.dqio_sem){++++}-{3:3}:
       down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498
       v2_read_dquot+0x4a/0x110 fs/quota/quota_v2.c:332
       dquot_acquire+0x152/0x520 fs/quota/dquot.c:488
       ext4_acquire_dquot+0x2e3/0x4a0 fs/ext4/super.c:6232
       dqget+0x713/0xbb0 fs/quota/dquot.c:1010
       __dquot_initialize+0x3a9/0xd00 fs/quota/dquot.c:1539
       ext4_process_orphan+0x4c/0x2e0 fs/ext4/orphan.c:327
       ext4_orphan_cleanup+0xad8/0x1320 fs/ext4/orphan.c:472
       ext4_fill_super+0x8c65/0x93f0 fs/ext4/super.c:5006
       mount_bdev+0x28a/0x3c0 fs/super.c:1400
       legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
       vfs_get_tree+0x88/0x270 fs/super.c:1530
       do_new_mount+0x247/0xa40 fs/namespace.c:3034
       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 (&dquot->dq_lock){+.+.}-{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
       __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_free_space+0x7c3/0xb80 fs/quota/dquot.c:1964
       dquot_free_space_nodirty include/linux/quotaops.h:369 [inline]
       dquot_free_space include/linux/quotaops.h:374 [inline]
       dquot_free_block include/linux/quotaops.h:385 [inline]
       ext4_mb_clear_bb fs/ext4/mballoc.c:6164 [inline]
       ext4_free_blocks+0x1b1b/0x24c0 fs/ext4/mballoc.c:6294
       ext4_remove_blocks fs/ext4/extents.c:2540 [inline]
       ext4_ext_rm_leaf fs/ext4/extents.c:2706 [inline]
       ext4_ext_remove_space+0x2106/0x41a0 fs/ext4/extents.c:2954
       ext4_ext_truncate+0x182/0x230 fs/ext4/extents.c:4504
       ext4_truncate+0xa41/0x1190 fs/ext4/inode.c:4263
       ext4_evict_inode+0xb0f/0x1050 fs/ext4/inode.c:291
       evict+0x4b6/0x8b0 fs/inode.c:647
       ext4_orphan_cleanup+0xad8/0x1320 fs/ext4/orphan.c:472
       ext4_fill_super+0x8c65/0x93f0 fs/ext4/super.c:5006
       mount_bdev+0x28a/0x3c0 fs/super.c:1400
       legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
       vfs_get_tree+0x88/0x270 fs/super.c:1530
       do_new_mount+0x247/0xa40 fs/namespace.c:3034
       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

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.0.57/4400:
 #0: ffff88807a11e0e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x200/0x970 fs/super.c:229
 #1: ffff88807a11e650 (sb_internal){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
 #1: ffff88807a11e650 (sb_internal){.+.+}-{0:0}, at: sb_start_intwrite include/linux/fs.h:1928 [inline]
 #1: ffff88807a11e650 (sb_internal){.+.+}-{0:0}, at: ext4_evict_inode+0x41f/0x1050 fs/ext4/inode.c:245
 #2: ffff888068aca060 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_truncate+0x994/0x1190 fs/ext4/inode.c:4258
 #3: ffffffff8c441798 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312

stack backtrace:
CPU: 1 PID: 4400 Comm: syz.0.57 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
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
 __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_free_space+0x7c3/0xb80 fs/quota/dquot.c:1964
 dquot_free_space_nodirty include/linux/quotaops.h:369 [inline]
 dquot_free_space include/linux/quotaops.h:374 [inline]
 dquot_free_block include/linux/quotaops.h:385 [inline]
 ext4_mb_clear_bb fs/ext4/mballoc.c:6164 [inline]
 ext4_free_blocks+0x1b1b/0x24c0 fs/ext4/mballoc.c:6294
 ext4_remove_blocks fs/ext4/extents.c:2540 [inline]
 ext4_ext_rm_leaf fs/ext4/extents.c:2706 [inline]
 ext4_ext_remove_space+0x2106/0x41a0 fs/ext4/extents.c:2954
 ext4_ext_truncate+0x182/0x230 fs/ext4/extents.c:4504
 ext4_truncate+0xa41/0x1190 fs/ext4/inode.c:4263
 ext4_evict_inode+0xb0f/0x1050 fs/ext4/inode.c:291
 evict+0x4b6/0x8b0 fs/inode.c:647
 ext4_orphan_cleanup+0xad8/0x1320 fs/ext4/orphan.c:472
 ext4_fill_super+0x8c65/0x93f0 fs/ext4/super.c:5006
 mount_bdev+0x28a/0x3c0 fs/super.c:1400
 legacy_get_tree+0xe6/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x247/0xa40 fs/namespace.c:3034
 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
RIP: 0033:0x7f1cccdd80ca
Code: 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 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:00007fff856d5418 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fff856d54a0 RCX: 00007f1cccdd80ca
RDX: 0000200000000100 RSI: 0000200000000200 RDI: 00007fff856d5460
RBP: 0000200000000100 R08: 00007fff856d54a0 R09: 0000000002000005
R10: 0000000002000005 R11: 0000000000000246 R12: 0000200000000200
R13: 00007fff856d5460 R14: 00000000000004fa R15: 0000200000003340
 </TASK>
EXT4-fs (loop0): 1 orphan inode deleted
EXT4-fs (loop0): mounted filesystem without journal. Opts: ,errors=continue. Quota mode: writeback.