====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.1957/19691 is trying to acquire lock: ffff88805f2bb450 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x33c/0x1b30 fs/ext4/inode.c:598 but task is already holding lock: ffff888020196208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x12b/0x190 fs/quota/quota_v2.c:354 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:6205 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:325 ext4_orphan_cleanup+0xad2/0x1320 fs/ext4/orphan.c:470 ext4_fill_super+0x92c9/0x9a40 fs/ext4/super.c:4975 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:6185 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:5734 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_write+0x236/0x580 fs/ext4/super.c:6596 write_blk fs/quota/quota_tree.c:64 [inline] get_free_dqblk+0x387/0x7d0 fs/quota/quota_tree.c:125 find_free_dqentry fs/quota/quota_tree.c:271 [inline] do_insert_tree+0xc9a/0x1970 fs/quota/quota_tree.c:364 do_insert_tree+0x5b1/0x1970 fs/quota/quota_tree.c:366 do_insert_tree+0x5b1/0x1970 fs/quota/quota_tree.c:366 do_insert_tree+0x5b1/0x1970 fs/quota/quota_tree.c:366 dq_insert_tree fs/quota/quota_tree.c:392 [inline] qtree_write_dquot+0x361/0x4b0 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:472 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6205 dqget+0x778/0xeb0 fs/quota/dquot.c:988 __dquot_initialize+0x333/0xcd0 fs/quota/dquot.c:1517 ext4_create+0x92/0x470 fs/ext4/namei.c:2876 lookup_open fs/namei.c:3470 [inline] open_last_lookups fs/namei.c:3540 [inline] path_openat+0x11db/0x2fa0 fs/namei.c:3747 do_filp_open+0x1e2/0x410 fs/namei.c:3777 do_sys_openat2+0x150/0x4b0 fs/open.c:1255 do_sys_open fs/open.c:1271 [inline] __do_sys_openat fs/open.c:1287 [inline] __se_sys_openat fs/open.c:1282 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1282 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 *** 4 locks held by syz.2.1957/19691: #0: ffff888020196460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386 #1: ffff8880530a49b8 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline] #1: ffff8880530a49b8 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: open_last_lookups fs/namei.c:3537 [inline] #1: ffff8880530a49b8 (&type->i_mutex_dir_key#4){++++}-{3:3}, at: path_openat+0x803/0x2fa0 fs/namei.c:3747 #2: ffff888072078268 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_acquire+0x63/0x520 fs/quota/dquot.c:460 #3: ffff888020196208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x12b/0x190 fs/quota/quota_v2.c:354 stack backtrace: CPU: 1 PID: 19691 Comm: syz.2.1957 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_write+0x236/0x580 fs/ext4/super.c:6596 write_blk fs/quota/quota_tree.c:64 [inline] get_free_dqblk+0x387/0x7d0 fs/quota/quota_tree.c:125 find_free_dqentry fs/quota/quota_tree.c:271 [inline] do_insert_tree+0xc9a/0x1970 fs/quota/quota_tree.c:364 do_insert_tree+0x5b1/0x1970 fs/quota/quota_tree.c:366 do_insert_tree+0x5b1/0x1970 fs/quota/quota_tree.c:366 do_insert_tree+0x5b1/0x1970 fs/quota/quota_tree.c:366 dq_insert_tree fs/quota/quota_tree.c:392 [inline] qtree_write_dquot+0x361/0x4b0 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:472 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6205 dqget+0x778/0xeb0 fs/quota/dquot.c:988 __dquot_initialize+0x333/0xcd0 fs/quota/dquot.c:1517 ext4_create+0x92/0x470 fs/ext4/namei.c:2876 lookup_open fs/namei.c:3470 [inline] open_last_lookups fs/namei.c:3540 [inline] path_openat+0x11db/0x2fa0 fs/namei.c:3747 do_filp_open+0x1e2/0x410 fs/namei.c:3777 do_sys_openat2+0x150/0x4b0 fs/open.c:1255 do_sys_open fs/open.c:1271 [inline] __do_sys_openat fs/open.c:1287 [inline] __se_sys_openat fs/open.c:1282 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1282 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: 0033:0x7f88978f3cb9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f8895b2e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f8897b6f090 RCX: 00007f88978f3cb9 RDX: 000000000000275a RSI: 0000200000000040 RDI: ffffffffffffff9c RBP: 00007f8897961bf7 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f8897b6f128 R14: 00007f8897b6f090 R15: 00007ffe24643008