====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.1.496/6019 is trying to acquire lock: ffff88805ea32a58 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x33c/0x1b30 fs/ext4/inode.c:598 but task is already holding lock: ffff8880659a0208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_read_dquot+0x4a/0x110 fs/quota/quota_v2.c:332 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&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:463 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6230 dqget+0x778/0xeb0 fs/quota/dquot.c:988 __dquot_initialize+0x3c3/0xcd0 fs/quota/dquot.c:1517 ext4_process_orphan+0x54/0x300 fs/ext4/orphan.c:327 ext4_orphan_cleanup+0xad2/0x1320 fs/ext4/orphan.c:472 ext4_fill_super+0x8e25/0x95a0 fs/ext4/super.c:5000 mount_bdev+0x287/0x3c0 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+0x24a/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 (&dquot->dq_lock){+.+.}-{3:3}: __mutex_lock_common+0x1e3/0x2400 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:507 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6210 mark_dquot_dirty fs/quota/dquot.c:372 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:412 __dquot_alloc_space+0x5d0/0xe20 fs/quota/dquot.c:1752 dquot_alloc_space_nodirty include/linux/quotaops.h:297 [inline] dquot_alloc_space include/linux/quotaops.h:310 [inline] dquot_alloc_block include/linux/quotaops.h:334 [inline] ext4_mb_new_blocks+0xf81/0x4980 fs/ext4/mballoc.c:5750 ext4_ext_map_blocks+0x191c/0x6580 fs/ext4/extents.c:4341 ext4_map_blocks+0x98e/0x1b30 fs/ext4/inode.c:673 ext4_getblk+0x176/0x670 fs/ext4/inode.c:870 ext4_bread+0x26/0x180 fs/ext4/inode.c:923 ext4_append+0x2be/0x560 fs/ext4/namei.c:83 ext4_init_new_dir+0x2a2/0x940 fs/ext4/namei.c:3030 ext4_mkdir+0x4fb/0xce0 fs/ext4/namei.c:3076 vfs_mkdir+0x387/0x570 fs/namei.c:4073 do_mkdirat+0x1df/0x5b0 fs/namei.c:4098 __do_sys_mkdirat fs/namei.c:4113 [inline] __se_sys_mkdirat fs/namei.c:4111 [inline] __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4111 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 (&ei->i_data_sem/2){++++}-{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+0x2c42/0x7d10 kernel/locking/lockdep.c:5012 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623 down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498 ext4_map_blocks+0x33c/0x1b30 fs/ext4/inode.c:598 ext4_getblk+0x176/0x670 fs/ext4/inode.c:870 ext4_bread+0x26/0x180 fs/ext4/inode.c:923 ext4_quota_read+0x1b3/0x3a0 fs/ext4/super.c:6575 read_blk fs/quota/quota_tree.c:55 [inline] find_tree_dqentry+0x188/0xb30 fs/quota/quota_tree.c:617 find_tree_dqentry+0x3eb/0xb30 fs/quota/quota_tree.c:635 find_tree_dqentry+0x3eb/0xb30 fs/quota/quota_tree.c:635 find_tree_dqentry+0x3eb/0xb30 fs/quota/quota_tree.c:635 find_dqentry fs/quota/quota_tree.c:647 [inline] qtree_read_dquot+0x13c/0x680 fs/quota/quota_tree.c:667 v2_read_dquot+0xc0/0x110 fs/quota/quota_v2.c:333 dquot_acquire+0x152/0x520 fs/quota/dquot.c:463 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6230 dqget+0x778/0xeb0 fs/quota/dquot.c:988 __dquot_initialize+0x333/0xcd0 fs/quota/dquot.c:1517 ext4_process_orphan+0x54/0x300 fs/ext4/orphan.c:327 ext4_orphan_cleanup+0xad2/0x1320 fs/ext4/orphan.c:472 ext4_fill_super+0x8e25/0x95a0 fs/ext4/super.c:5000 mount_bdev+0x287/0x3c0 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+0x24a/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: &ei->i_data_sem/2 --> &dquot->dq_lock --> &s->s_dquot.dqio_sem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&s->s_dquot.dqio_sem); lock(&dquot->dq_lock); lock(&s->s_dquot.dqio_sem); lock(&ei->i_data_sem/2); *** DEADLOCK *** 3 locks held by syz.1.496/6019: #0: ffff8880659a00e0 (&type->s_umount_key#28/1){+.+.}-{3:3}, at: alloc_super+0x201/0x950 fs/super.c:229 #1: ffff88807446e5e8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_acquire+0x63/0x520 fs/quota/dquot.c:460 #2: ffff8880659a0208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_read_dquot+0x4a/0x110 fs/quota/quota_v2.c:332 stack backtrace: CPU: 0 PID: 6019 Comm: syz.1.496 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: 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+0x2c42/0x7d10 kernel/locking/lockdep.c:5012 lock_acquire+0x19e/0x400 kernel/locking/lockdep.c:5623 down_read+0x44/0x2e0 kernel/locking/rwsem.c:1498 ext4_map_blocks+0x33c/0x1b30 fs/ext4/inode.c:598 ext4_getblk+0x176/0x670 fs/ext4/inode.c:870 ext4_bread+0x26/0x180 fs/ext4/inode.c:923 ext4_quota_read+0x1b3/0x3a0 fs/ext4/super.c:6575 read_blk fs/quota/quota_tree.c:55 [inline] find_tree_dqentry+0x188/0xb30 fs/quota/quota_tree.c:617 find_tree_dqentry+0x3eb/0xb30 fs/quota/quota_tree.c:635 find_tree_dqentry+0x3eb/0xb30 fs/quota/quota_tree.c:635 find_tree_dqentry+0x3eb/0xb30 fs/quota/quota_tree.c:635 find_dqentry fs/quota/quota_tree.c:647 [inline] qtree_read_dquot+0x13c/0x680 fs/quota/quota_tree.c:667 v2_read_dquot+0xc0/0x110 fs/quota/quota_v2.c:333 dquot_acquire+0x152/0x520 fs/quota/dquot.c:463 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6230 dqget+0x778/0xeb0 fs/quota/dquot.c:988 __dquot_initialize+0x333/0xcd0 fs/quota/dquot.c:1517 ext4_process_orphan+0x54/0x300 fs/ext4/orphan.c:327 ext4_orphan_cleanup+0xad2/0x1320 fs/ext4/orphan.c:472 ext4_fill_super+0x8e25/0x95a0 fs/ext4/super.c:5000 mount_bdev+0x287/0x3c0 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+0x24a/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: 0033:0x7fb8eeaa0f4a 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:00007fb8eccfae58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fb8eccfaee0 RCX: 00007fb8eeaa0f4a RDX: 0000200000000040 RSI: 0000200000000a00 RDI: 00007fb8eccfaea0 RBP: 0000200000000040 R08: 00007fb8eccfaee0 R09: 0000000001008413 R10: 0000000001008413 R11: 0000000000000246 R12: 0000200000000a00 R13: 00007fb8eccfaea0 R14: 0000000000000525 R15: 0000200000000140 EXT4-fs error (device loop1): ext4_validate_block_bitmap:438: comm syz.1.496: bg 0: block 34: padding at end of block bitmap is not set Quota error (device loop1): write_blk: dquota write failed Quota error (device loop1): qtree_write_dquot: Error -28 occurred while creating quota EXT4-fs error (device loop1): ext4_acquire_dquot:6234: comm syz.1.496: Failed to acquire dquot type 1 EXT4-fs (loop1): ext4_process_orphan: truncating inode 13 to 1050 bytes EXT4-fs (loop1): 1 truncate cleaned up EXT4-fs (loop1): mounted filesystem without journal. Opts: noload,bsdgroups,barrier=0x0000000000000003,noblock_validity,,errors=continue. Quota mode: writeback.