syzbot

======================================================
WARNING: possible circular locking dependency detected
6.1.141-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor402/4483 is trying to acquire lock:
ffff88806e425068 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:507

but task is already holding lock:
ffff8880713c0c90 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_truncate+0x987/0x1230 fs/ext4/inode.c:4284

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+0x42/0x2d0 kernel/locking/rwsem.c:1520
       ext4_map_blocks+0x316/0x1b60 fs/ext4/inode.c:604
       ext4_getblk+0x1ab/0x6d0 fs/ext4/inode.c:890
       ext4_bread+0x26/0x170 fs/ext4/inode.c:946
       ext4_quota_write+0x230/0x570 fs/ext4/super.c:7201
       write_blk fs/quota/quota_tree.c:70 [inline]
       get_free_dqblk+0x312/0x660 fs/quota/quota_tree.c:136
       do_insert_tree+0x22b/0x1040 fs/quota/quota_tree.c:347
       do_insert_tree+0x9eb/0x1040 fs/quota/quota_tree.c:402
       do_insert_tree+0x9eb/0x1040 fs/quota/quota_tree.c:402
       do_insert_tree+0x9eb/0x1040 fs/quota/quota_tree.c:402
       dq_insert_tree fs/quota/quota_tree.c:432 [inline]
       qtree_write_dquot+0x48d/0x5b0 fs/quota/quota_tree.c:451
       v2_write_dquot+0x108/0x190 fs/quota/quota_v2.c:361
       dquot_acquire+0x2d5/0x520 fs/quota/dquot.c:472
       ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6810
       dqget+0x778/0xeb0 fs/quota/dquot.c:988
       __dquot_initialize+0x3b6/0xcb0 fs/quota/dquot.c:1517
       ext4_file_open+0x2cb/0x6a0 fs/ext4/file.c:872
       do_dentry_open+0x7e9/0x10d0 fs/open.c:882
       do_open fs/namei.c:3626 [inline]
       path_openat+0x25c6/0x2e70 fs/namei.c:3783
       do_filp_open+0x1c1/0x3c0 fs/namei.c:3810
       do_sys_openat2+0x142/0x490 fs/open.c:1318
       do_sys_open fs/open.c:1334 [inline]
       __do_sys_creat fs/open.c:1412 [inline]
       __se_sys_creat fs/open.c:1406 [inline]
       __x64_sys_creat+0x8c/0xb0 fs/open.c:1406
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
       entry_SYSCALL_64_after_hwframe+0x68/0xd2

-> #1 (&s->s_dquot.dqio_sem){++++}-{3:3}:
       down_read+0x42/0x2d0 kernel/locking/rwsem.c:1520
       v2_read_dquot+0x4a/0x110 fs/quota/quota_v2.c:335
       dquot_acquire+0x152/0x520 fs/quota/dquot.c:463
       ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6810
       dqget+0x778/0xeb0 fs/quota/dquot.c:988
       __dquot_initialize+0x3b6/0xcb0 fs/quota/dquot.c:1517
       ext4_file_open+0x2cb/0x6a0 fs/ext4/file.c:872
       do_dentry_open+0x7e9/0x10d0 fs/open.c:882
       do_open fs/namei.c:3626 [inline]
       path_openat+0x25c6/0x2e70 fs/namei.c:3783
       do_filp_open+0x1c1/0x3c0 fs/namei.c:3810
       do_sys_openat2+0x142/0x490 fs/open.c:1318
       do_sys_open fs/open.c:1334 [inline]
       __do_sys_creat fs/open.c:1412 [inline]
       __se_sys_creat fs/open.c:1406 [inline]
       __x64_sys_creat+0x8c/0xb0 fs/open.c:1406
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x4c/0xa0 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:3090 [inline]
       check_prevs_add kernel/locking/lockdep.c:3209 [inline]
       validate_chain kernel/locking/lockdep.c:3825 [inline]
       __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
       lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
       __mutex_lock_common kernel/locking/mutex.c:603 [inline]
       __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
       dquot_commit+0x5a/0x410 fs/quota/dquot.c:507
       ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6790
       mark_dquot_dirty fs/quota/dquot.c:372 [inline]
       mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:412
       __dquot_free_space+0x7ec/0xbc0 fs/quota/dquot.c:1942
       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:6143 [inline]
       ext4_free_blocks+0x1bab/0x2640 fs/ext4/mballoc.c:6273
       ext4_remove_blocks fs/ext4/extents.c:2507 [inline]
       ext4_ext_rm_leaf fs/ext4/extents.c:2691 [inline]
       ext4_ext_remove_space+0x1dd3/0x4490 fs/ext4/extents.c:2939
       ext4_ext_truncate+0x211/0x370 fs/ext4/extents.c:4469
       ext4_truncate+0xa0b/0x1230 fs/ext4/inode.c:4289
       ext4_setattr+0x10cb/0x19f0 fs/ext4/inode.c:5630
       notify_change+0xc74/0xf40 fs/attr.c:499
       do_truncate+0x197/0x220 fs/open.c:65
       handle_truncate fs/namei.c:3285 [inline]
       do_open fs/namei.c:3630 [inline]
       path_openat+0x27f2/0x2e70 fs/namei.c:3783
       do_filp_open+0x1c1/0x3c0 fs/namei.c:3810
       do_sys_openat2+0x142/0x490 fs/open.c:1318
       do_sys_open fs/open.c:1334 [inline]
       __do_sys_creat fs/open.c:1412 [inline]
       __se_sys_creat fs/open.c:1406 [inline]
       __x64_sys_creat+0x8c/0xb0 fs/open.c:1406
       do_syscall_x64 arch/x86/entry/common.c:51 [inline]
       do_syscall_64+0x4c/0xa0 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 --> &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 ***

5 locks held by syz-executor402/4483:
 #0: ffff8880760d0460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:393
 #1: ffff8880713c0e08 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline]
 #1: ffff8880713c0e08 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: do_truncate+0x183/0x220 fs/open.c:63
 #2: ffff8880713c0fa8 (mapping.invalidate_lock){++++}-{3:3}, at: filemap_invalidate_lock include/linux/fs.h:803 [inline]
 #2: ffff8880713c0fa8 (mapping.invalidate_lock){++++}-{3:3}, at: ext4_setattr+0xe6f/0x19f0 fs/ext4/inode.c:5553
 #3: ffff8880713c0c90 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_truncate+0x987/0x1230 fs/ext4/inode.c:4284
 #4: ffffffff8ca74d08 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #4: ffffffff8ca74d08 (dquot_srcu){....}-{0:0}, at: srcu_read_lock include/linux/srcu.h:165 [inline]
 #4: ffffffff8ca74d08 (dquot_srcu){....}-{0:0}, at: __dquot_free_space+0x174/0xbc0 fs/quota/dquot.c:1915

stack backtrace:
CPU: 1 PID: 4483 Comm: syz-executor402 Not tainted 6.1.141-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 check_noncircular+0x274/0x310 kernel/locking/lockdep.c:2170
 check_prev_add kernel/locking/lockdep.c:3090 [inline]
 check_prevs_add kernel/locking/lockdep.c:3209 [inline]
 validate_chain kernel/locking/lockdep.c:3825 [inline]
 __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049
 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
 __mutex_lock_common kernel/locking/mutex.c:603 [inline]
 __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747
 dquot_commit+0x5a/0x410 fs/quota/dquot.c:507
 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6790
 mark_dquot_dirty fs/quota/dquot.c:372 [inline]
 mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:412
 __dquot_free_space+0x7ec/0xbc0 fs/quota/dquot.c:1942
 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:6143 [inline]
 ext4_free_blocks+0x1bab/0x2640 fs/ext4/mballoc.c:6273
 ext4_remove_blocks fs/ext4/extents.c:2507 [inline]
 ext4_ext_rm_leaf fs/ext4/extents.c:2691 [inline]
 ext4_ext_remove_space+0x1dd3/0x4490 fs/ext4/extents.c:2939
 ext4_ext_truncate+0x211/0x370 fs/ext4/extents.c:4469
 ext4_truncate+0xa0b/0x1230 fs/ext4/inode.c:4289
 ext4_setattr+0x10cb/0x19f0 fs/ext4/inode.c:5630
 notify_change+0xc74/0xf40 fs/attr.c:499
 do_truncate+0x197/0x220 fs/open.c:65
 handle_truncate fs/namei.c:3285 [inline]
 do_open fs/namei.c:3630 [inline]
 path_openat+0x27f2/0x2e70 fs/namei.c:3783
 do_filp_open+0x1c1/0x3c0 fs/namei.c:3810
 do_sys_openat2+0x142/0x490 fs/open.c:1318
 do_sys_open fs/open.c:1334 [inline]
 __do_sys_creat fs/open.c:1412 [inline]
 __se_sys_creat fs/open.c:1406 [inline]
 __x64_sys_creat+0x8c/0xb0 fs/open.c:1406
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff749f154d9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 21 18 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc6b61cd28 EFLAGS: 00000246 ORIG_RAX: 0000000000000055
RAX: ffffffffffffffda RBX: 00002000000000c0 RCX: 00007ff749f154d9
RDX: 00007ff749f14670 RSI: 00000000000000e0 RDI: 0000200000000100
RBP: 0031656c69662f2e R08: 0000000000000bcb R09: 0000200000002380
R10: 00007ffc6b61cbf0 R11: 0000000000000246 R12: 00007ffc6b61cd5c
R13: 0000000000000020 R14: 431bde82d7b634db R15: 00007ffc6b61cd90
 </TASK>
EXT4-fs error (device loop3): ext4_do_update_inode:5253: inode #15: comm syz-executor402: corrupted inode contents
EXT4-fs error (device loop3): ext4_dirty_inode:6118: inode #15: comm syz-executor402: mark_inode_dirty error
EXT4-fs error (device loop3): ext4_do_update_inode:5253: inode #15: comm syz-executor402: corrupted inode contents
EXT4-fs error (device loop3): __ext4_ext_dirty:202: inode #15: comm syz-executor402: mark_inode_dirty error
EXT4-fs error (device loop3): ext4_do_update_inode:5253: inode #15: comm syz-executor402: corrupted inode contents
EXT4-fs error (device loop3): __ext4_ext_dirty:202: inode #15: comm syz-executor402: mark_inode_dirty error
EXT4-fs error (device loop3): ext4_do_update_inode:5253: inode #15: comm syz-executor402: corrupted inode contents
EXT4-fs error (device loop3): ext4_truncate:4312: inode #15: comm syz-executor402: mark_inode_dirty error
EXT4-fs error (device loop3) in ext4_setattr:5657: Corrupt filesystem
EXT4-fs (loop3): re-mounted. Quota mode: writeback.
EXT4-fs (loop3): warning: mounting fs with errors, running e2fsck is recommended
EXT4-fs (loop3): re-mounted. Quota mode: writeback.