syzbot

loop0: detected capacity change from 0 to 512
EXT4-fs (loop0): orphan cleanup on readonly fs
======================================================
WARNING: possible circular locking dependency detected
5.15.179-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor260/4310 is trying to acquire lock:
ffff8880702bdca8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x57/0x510 fs/quota/dquot.c:507

but task is already holding lock:
ffff8880701cc840 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_truncate+0x974/0x1130 fs/ext4/inode.c:4244

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+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       down_read+0x45/0x2e0 kernel/locking/rwsem.c:1498
       ext4_map_blocks+0x391/0x1c70 fs/ext4/inode.c:597
       ext4_getblk+0x19f/0x710 fs/ext4/inode.c:869
       ext4_bread+0x2a/0x170 fs/ext4/inode.c:922
       ext4_quota_read+0x1a1/0x2c0 fs/ext4/super.c:6521
       read_blk fs/quota/quota_tree.c:55 [inline]
       find_tree_dqentry+0x192/0xb60 fs/quota/quota_tree.c:617
       find_tree_dqentry+0x41a/0xb60 fs/quota/quota_tree.c:635
       find_dqentry fs/quota/quota_tree.c:647 [inline]
       qtree_read_dquot+0x13f/0x650 fs/quota/quota_tree.c:667
       v2_read_dquot+0xbe/0x100 fs/quota/quota_v2.c:333
       dquot_acquire+0x188/0x680 fs/quota/dquot.c:463
       ext4_acquire_dquot+0x2eb/0x4a0 fs/ext4/super.c:6193
       dqget+0x762/0xe90 fs/quota/dquot.c:988
       __dquot_initialize+0x2d9/0xea0 fs/quota/dquot.c:1517
       ext4_process_orphan+0x57/0x2d0 fs/ext4/orphan.c:329
       ext4_orphan_cleanup+0x9d9/0x1240 fs/ext4/orphan.c:474
       ext4_fill_super+0x98de/0xa110 fs/ext4/super.c:4975
       mount_bdev+0x2c9/0x3f0 fs/super.c:1400
       legacy_get_tree+0xeb/0x180 fs/fs_context.c:611
       vfs_get_tree+0x88/0x270 fs/super.c:1530
       do_new_mount+0x2ba/0xb40 fs/namespace.c:3012
       do_mount fs/namespace.c:3355 [inline]
       __do_sys_mount fs/namespace.c:3563 [inline]
       __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3540
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #1 (&s->s_dquot.dqio_sem){++++}-{3:3}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       down_read+0x45/0x2e0 kernel/locking/rwsem.c:1498
       v2_read_dquot+0x4a/0x100 fs/quota/quota_v2.c:332
       dquot_acquire+0x188/0x680 fs/quota/dquot.c:463
       ext4_acquire_dquot+0x2eb/0x4a0 fs/ext4/super.c:6193
       dqget+0x762/0xe90 fs/quota/dquot.c:988
       __dquot_initialize+0x2d9/0xea0 fs/quota/dquot.c:1517
       ext4_process_orphan+0x57/0x2d0 fs/ext4/orphan.c:329
       ext4_orphan_cleanup+0x9d9/0x1240 fs/ext4/orphan.c:474
       ext4_fill_super+0x98de/0xa110 fs/ext4/super.c:4975
       mount_bdev+0x2c9/0x3f0 fs/super.c:1400
       legacy_get_tree+0xeb/0x180 fs/fs_context.c:611
       vfs_get_tree+0x88/0x270 fs/super.c:1530
       do_new_mount+0x2ba/0xb40 fs/namespace.c:3012
       do_mount fs/namespace.c:3355 [inline]
       __do_sys_mount fs/namespace.c:3563 [inline]
       __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3540
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 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+0x1649/0x5930 kernel/locking/lockdep.c:3788
       __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __mutex_lock_common+0x1da/0x25a0 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+0x57/0x510 fs/quota/dquot.c:507
       ext4_write_dquot+0x1fd/0x360 fs/ext4/super.c:6173
       mark_dquot_dirty fs/quota/dquot.c:372 [inline]
       mark_all_dquot_dirty+0xf7/0x400 fs/quota/dquot.c:412
       __dquot_free_space+0x932/0xe40 fs/quota/dquot.c:1942
       dquot_free_space_nodirty include/linux/quotaops.h:376 [inline]
       dquot_free_space include/linux/quotaops.h:381 [inline]
       dquot_free_block include/linux/quotaops.h:392 [inline]
       ext4_mb_clear_bb fs/ext4/mballoc.c:6156 [inline]
       ext4_free_blocks+0x1f5c/0x2e90 fs/ext4/mballoc.c:6286
       ext4_remove_blocks fs/ext4/extents.c:2523 [inline]
       ext4_ext_rm_leaf fs/ext4/extents.c:2689 [inline]
       ext4_ext_remove_space+0x24da/0x4db0 fs/ext4/extents.c:2937
       ext4_ext_truncate+0x191/0x250 fs/ext4/extents.c:4471
       ext4_truncate+0x9fd/0x1130 fs/ext4/inode.c:4249
       ext4_evict_inode+0xba1/0x1100 fs/ext4/inode.c:289
       evict+0x529/0x930 fs/inode.c:647
       ext4_orphan_cleanup+0x9d9/0x1240 fs/ext4/orphan.c:474
       ext4_fill_super+0x98de/0xa110 fs/ext4/super.c:4975
       mount_bdev+0x2c9/0x3f0 fs/super.c:1400
       legacy_get_tree+0xeb/0x180 fs/fs_context.c:611
       vfs_get_tree+0x88/0x270 fs/super.c:1530
       do_new_mount+0x2ba/0xb40 fs/namespace.c:3012
       do_mount fs/namespace.c:3355 [inline]
       __do_sys_mount fs/namespace.c:3563 [inline]
       __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3540
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 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-executor260/4310:
 #0: ffff88807ad980e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x210/0x940 fs/super.c:229
 #1: ffff88807ad98650 (sb_internal){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1811 [inline]
 #1: ffff88807ad98650 (sb_internal){.+.+}-{0:0}, at: sb_start_intwrite include/linux/fs.h:1928 [inline]
 #1: ffff88807ad98650 (sb_internal){.+.+}-{0:0}, at: ext4_evict_inode+0x375/0x1100 fs/ext4/inode.c:243
 #2: ffff8880701cc840 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_truncate+0x974/0x1130 fs/ext4/inode.c:4244
 #3: ffffffff8cc446b8 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311

stack backtrace:
CPU: 0 PID: 4310 Comm: syz-executor260 Not tainted 5.15.179-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x2f8/0x3b0 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+0x1649/0x5930 kernel/locking/lockdep.c:3788
 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 __mutex_lock_common+0x1da/0x25a0 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+0x57/0x510 fs/quota/dquot.c:507
 ext4_write_dquot+0x1fd/0x360 fs/ext4/super.c:6173
 mark_dquot_dirty fs/quota/dquot.c:372 [inline]
 mark_all_dquot_dirty+0xf7/0x400 fs/quota/dquot.c:412
 __dquot_free_space+0x932/0xe40 fs/quota/dquot.c:1942
 dquot_free_space_nodirty include/linux/quotaops.h:376 [inline]
 dquot_free_space include/linux/quotaops.h:381 [inline]
 dquot_free_block include/linux/quotaops.h:392 [inline]
 ext4_mb_clear_bb fs/ext4/mballoc.c:6156 [inline]
 ext4_free_blocks+0x1f5c/0x2e90 fs/ext4/mballoc.c:6286
 ext4_remove_blocks fs/ext4/extents.c:2523 [inline]
 ext4_ext_rm_leaf fs/ext4/extents.c:2689 [inline]
 ext4_ext_remove_space+0x24da/0x4db0 fs/ext4/extents.c:2937
 ext4_ext_truncate+0x191/0x250 fs/ext4/extents.c:4471
 ext4_truncate+0x9fd/0x1130 fs/ext4/inode.c:4249
 ext4_evict_inode+0xba1/0x1100 fs/ext4/inode.c:289
 evict+0x529/0x930 fs/inode.c:647
 ext4_orphan_cleanup+0x9d9/0x1240 fs/ext4/orphan.c:474
 ext4_fill_super+0x98de/0xa110 fs/ext4/super.c:4975
 mount_bdev+0x2c9/0x3f0 fs/super.c:1400
 legacy_get_tree+0xeb/0x180 fs/fs_context.c:611
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x2ba/0xb40 fs/namespace.c:3012
 do_mount fs/namespace.c:3355 [inline]
 __do_sys_mount fs/namespace.c:3563 [inline]
 __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3540
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fdcf34f14aa
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 5e 04 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffd54d20ad8 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fdcf34f14aa
RDX: 0000400000000040 RSI: 0000400000000000 RDI: 00007ffd54d20b20
RBP: 0000000000000004 R08: 00007ffd54d20b60 R09: 00000000000004ad
R10: 0000000000004517 R11: 0000000000000206 R12: 0000000000040000
R13: 00007ffd54d20b60 R14: 0000400000000000 R15: 0000000000000003
 </TASK>
EXT4-fs (loop0): 1 orphan inode deleted