====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.4102/21351 is trying to acquire lock: ffff8880753b1698 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x914/0x1a90 fs/ext4/inode.c:674 but task is already holding lock: ffff888052da8208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x12b/0x190 fs/quota/quota_v2.c:357 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+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:491 ext4_acquire_dquot+0x2e3/0x4a0 fs/ext4/super.c:6837 dqget+0x713/0xbb0 fs/quota/dquot.c:1013 __dquot_initialize+0x3a9/0xd00 fs/quota/dquot.c:1542 ext4_create+0x92/0x470 fs/ext4/namei.c:2876 lookup_open fs/namei.c:3490 [inline] open_last_lookups fs/namei.c:3558 [inline] path_openat+0x11b9/0x2f10 fs/namei.c:3788 do_filp_open+0x1ee/0x420 fs/namei.c:3818 do_sys_openat2+0x14b/0x4f0 fs/open.c:1320 do_sys_open fs/open.c:1336 [inline] __do_sys_openat fs/open.c:1352 [inline] __se_sys_openat fs/open.c:1347 [inline] __x64_sys_openat+0x135/0x160 fs/open.c:1347 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #1 (&dquot->dq_lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xae0 kernel/locking/mutex.c:747 dquot_commit+0x5a/0x410 fs/quota/dquot.c:535 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6817 mark_dquot_dirty fs/quota/dquot.c:400 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:440 __dquot_free_space+0x7f8/0xbc0 fs/quota/dquot.c:1967 dquot_free_space_nodirty include/linux/quotaops.h:372 [inline] dquot_free_space include/linux/quotaops.h:377 [inline] dquot_free_block include/linux/quotaops.h:388 [inline] ext4_mb_clear_bb fs/ext4/mballoc.c:6153 [inline] ext4_free_blocks+0x1be5/0x26a0 fs/ext4/mballoc.c:6283 ext4_remove_blocks fs/ext4/extents.c:2523 [inline] ext4_ext_rm_leaf fs/ext4/extents.c:2707 [inline] ext4_ext_remove_space+0x22ba/0x43d0 fs/ext4/extents.c:2955 ext4_ext_truncate+0x213/0x370 fs/ext4/extents.c:4491 ext4_truncate+0xa5b/0x12a0 fs/ext4/inode.c:4302 ext4_evict_inode+0xb21/0x10e0 fs/ext4/inode.c:288 evict+0x4b6/0x8b0 fs/inode.c:705 d_delete_notify include/linux/fsnotify.h:267 [inline] vfs_rmdir+0x374/0x4a0 fs/namei.c:4212 do_rmdir+0x29a/0x5c0 fs/namei.c:4260 __do_sys_unlinkat fs/namei.c:4440 [inline] __se_sys_unlinkat fs/namei.c:4434 [inline] __x64_sys_unlinkat+0xc0/0xe0 fs/namei.c:4434 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (&ei->i_data_sem/2){++++}-{3:3}: check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3830 [inline] __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676 down_write+0x36/0x60 kernel/locking/rwsem.c:1573 ext4_map_blocks+0x914/0x1a90 fs/ext4/inode.c:674 ext4_getblk+0x1c5/0x720 fs/ext4/inode.c:892 ext4_bread+0x26/0x170 fs/ext4/inode.c:948 ext4_quota_write+0x237/0x580 fs/ext4/super.c:7228 write_blk fs/quota/quota_tree.c:70 [inline] get_free_dqblk+0x2dc/0x630 fs/quota/quota_tree.c:136 do_insert_tree+0x22b/0x1060 fs/quota/quota_tree.c:347 do_insert_tree+0x9f5/0x1060 fs/quota/quota_tree.c:402 do_insert_tree+0x9b8/0x1060 fs/quota/quota_tree.c:402 dq_insert_tree fs/quota/quota_tree.c:432 [inline] qtree_write_dquot+0x49b/0x5d0 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:500 ext4_acquire_dquot+0x2e3/0x4a0 fs/ext4/super.c:6837 dqget+0x713/0xbb0 fs/quota/dquot.c:1013 __dquot_initialize+0x3a9/0xd00 fs/quota/dquot.c:1542 ext4_xattr_set+0xc5/0x310 fs/ext4/xattr.c:2487 __vfs_setxattr+0x3d8/0x410 fs/xattr.c:182 __vfs_setxattr_noperm+0x126/0x5e0 fs/xattr.c:216 vfs_setxattr+0x167/0x2e0 fs/xattr.c:309 do_setxattr fs/xattr.c:594 [inline] setxattr+0x2a3/0x330 fs/xattr.c:617 path_setxattr+0x147/0x290 fs/xattr.c:636 __do_sys_lsetxattr fs/xattr.c:659 [inline] __se_sys_lsetxattr fs/xattr.c:655 [inline] __x64_sys_lsetxattr+0xb4/0xd0 fs/xattr.c:655 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 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.2.4102/21351: #0: ffff888052da8460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402 #1: ffff888056932218 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #1: ffff888056932218 (&type->i_mutex_dir_key#3){++++}-{3:3}, at: vfs_setxattr+0x140/0x2e0 fs/xattr.c:308 #2: ffff8880725a9e68 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_acquire+0x63/0x520 fs/quota/dquot.c:488 #3: ffff888052da8208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x12b/0x190 fs/quota/quota_v2.c:357 stack backtrace: CPU: 1 PID: 21351 Comm: syz.2.4102 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 check_noncircular+0x296/0x330 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3095 [inline] check_prevs_add kernel/locking/lockdep.c:3214 [inline] validate_chain kernel/locking/lockdep.c:3830 [inline] __lock_acquire+0x2d18/0x7c40 kernel/locking/lockdep.c:5063 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5676 down_write+0x36/0x60 kernel/locking/rwsem.c:1573 ext4_map_blocks+0x914/0x1a90 fs/ext4/inode.c:674 ext4_getblk+0x1c5/0x720 fs/ext4/inode.c:892 ext4_bread+0x26/0x170 fs/ext4/inode.c:948 ext4_quota_write+0x237/0x580 fs/ext4/super.c:7228 write_blk fs/quota/quota_tree.c:70 [inline] get_free_dqblk+0x2dc/0x630 fs/quota/quota_tree.c:136 do_insert_tree+0x22b/0x1060 fs/quota/quota_tree.c:347 do_insert_tree+0x9f5/0x1060 fs/quota/quota_tree.c:402 do_insert_tree+0x9b8/0x1060 fs/quota/quota_tree.c:402 dq_insert_tree fs/quota/quota_tree.c:432 [inline] qtree_write_dquot+0x49b/0x5d0 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:500 ext4_acquire_dquot+0x2e3/0x4a0 fs/ext4/super.c:6837 dqget+0x713/0xbb0 fs/quota/dquot.c:1013 __dquot_initialize+0x3a9/0xd00 fs/quota/dquot.c:1542 ext4_xattr_set+0xc5/0x310 fs/ext4/xattr.c:2487 __vfs_setxattr+0x3d8/0x410 fs/xattr.c:182 __vfs_setxattr_noperm+0x126/0x5e0 fs/xattr.c:216 vfs_setxattr+0x167/0x2e0 fs/xattr.c:309 do_setxattr fs/xattr.c:594 [inline] setxattr+0x2a3/0x330 fs/xattr.c:617 path_setxattr+0x147/0x290 fs/xattr.c:636 __do_sys_lsetxattr fs/xattr.c:659 [inline] __se_sys_lsetxattr fs/xattr.c:655 [inline] __x64_sys_lsetxattr+0xb4/0xd0 fs/xattr.c:655 do_syscall_x64 arch/x86/entry/common.c:46 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f166259e0d9 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:00007f16607f6028 EFLAGS: 00000246 ORIG_RAX: 00000000000000bd RAX: ffffffffffffffda RBX: 00007f1662826180 RCX: 00007f166259e0d9 RDX: 0000200000000100 RSI: 00002000000000c0 RDI: 0000200000000080 RBP: 00007f1662635024 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000018 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1662826218 R14: 00007f1662826180 R15: 00007ffcca6d6d58