====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz-executor/4475 is trying to acquire lock: ffff88805fd80c70 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x33c/0x1b30 fs/ext4/inode.c:600 but task is already holding lock: ffff88807b736208 (&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:488 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6232 dqget+0x72b/0xc30 fs/quota/dquot.c:1010 __dquot_initialize+0x3c3/0xcd0 fs/quota/dquot.c:1539 ext4_process_orphan+0x54/0x300 fs/ext4/orphan.c:327 ext4_orphan_cleanup+0xad2/0x1320 fs/ext4/orphan.c:472 ext4_fill_super+0x8d6e/0x94f0 fs/ext4/super.c:5006 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:532 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6212 mark_dquot_dirty fs/quota/dquot.c:397 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:437 __dquot_alloc_space+0x5d0/0xe20 fs/quota/dquot.c:1774 dquot_alloc_space_nodirty include/linux/quotaops.h:290 [inline] dquot_alloc_space include/linux/quotaops.h:303 [inline] dquot_alloc_block include/linux/quotaops.h:327 [inline] ext4_mb_new_blocks+0xfb1/0x4820 fs/ext4/mballoc.c:5750 ext4_ext_map_blocks+0x18ab/0x65e0 fs/ext4/extents.c:4357 ext4_map_blocks+0x98e/0x1b30 fs/ext4/inode.c:675 ext4_getblk+0x176/0x670 fs/ext4/inode.c:872 ext4_bread+0x26/0x180 fs/ext4/inode.c:925 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 ovl_do_mkdir fs/overlayfs/overlayfs.h:166 [inline] ovl_mkdir_real+0x53/0x1a0 fs/overlayfs/dir.c:146 ovl_workdir_create+0x2dd/0x630 fs/overlayfs/super.c:796 ovl_make_workdir fs/overlayfs/super.c:1376 [inline] ovl_get_workdir+0x37c/0x1230 fs/overlayfs/super.c:1526 ovl_fill_super+0x1824/0x2a30 fs/overlayfs/super.c:2082 mount_nodev+0x52/0xe0 fs/super.c:1446 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 -> #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:600 ext4_getblk+0x176/0x670 fs/ext4/inode.c:872 ext4_bread+0x26/0x180 fs/ext4/inode.c:925 ext4_quota_write+0x236/0x580 fs/ext4/super.c:6623 write_blk fs/quota/quota_tree.c:64 [inline] get_free_dqblk+0x387/0x7d0 fs/quota/quota_tree.c:125 do_insert_tree+0x214/0x1970 fs/quota/quota_tree.c:335 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:497 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6232 dqget+0x72b/0xc30 fs/quota/dquot.c:1010 __dquot_initialize+0x3c3/0xcd0 fs/quota/dquot.c:1539 ext4_unlink+0x168/0x500 fs/ext4/namei.c:3366 vfs_unlink+0x385/0x600 fs/namei.c:4288 do_unlinkat+0x391/0x710 fs/namei.c:4356 __do_sys_unlink fs/namei.c:4404 [inline] __se_sys_unlink fs/namei.c:4402 [inline] __x64_sys_unlink+0x45/0x50 fs/namei.c:4402 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 *** 5 locks held by syz-executor/4475: #0: ffff88807b736460 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:386 #1: ffff88807427dda8 (&type->i_mutex_dir_key#4/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:822 [inline] #1: ffff88807427dda8 (&type->i_mutex_dir_key#4/1){+.+.}-{3:3}, at: do_unlinkat+0x1c8/0x710 fs/namei.c:4339 #2: ffff88805fe703f0 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline] #2: ffff88805fe703f0 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: vfs_unlink+0xee/0x600 fs/namei.c:4277 #3: ffff88805fd3e7a8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_acquire+0x63/0x520 fs/quota/dquot.c:485 #4: ffff88807b736208 (&s->s_dquot.dqio_sem){++++}-{3:3}, at: v2_write_dquot+0x12b/0x190 fs/quota/quota_v2.c:354 stack backtrace: CPU: 0 PID: 4475 Comm: syz-executor Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 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:600 ext4_getblk+0x176/0x670 fs/ext4/inode.c:872 ext4_bread+0x26/0x180 fs/ext4/inode.c:925 ext4_quota_write+0x236/0x580 fs/ext4/super.c:6623 write_blk fs/quota/quota_tree.c:64 [inline] get_free_dqblk+0x387/0x7d0 fs/quota/quota_tree.c:125 do_insert_tree+0x214/0x1970 fs/quota/quota_tree.c:335 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:497 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6232 dqget+0x72b/0xc30 fs/quota/dquot.c:1010 __dquot_initialize+0x3c3/0xcd0 fs/quota/dquot.c:1539 ext4_unlink+0x168/0x500 fs/ext4/namei.c:3366 vfs_unlink+0x385/0x600 fs/namei.c:4288 do_unlinkat+0x391/0x710 fs/namei.c:4356 __do_sys_unlink fs/namei.c:4404 [inline] __se_sys_unlink fs/namei.c:4402 [inline] __x64_sys_unlink+0x45/0x50 fs/namei.c:4402 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: 0033:0x7f5862c46f47 Code: 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8 RSP: 002b:00007ffd60ed7948 EFLAGS: 00000206 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5862c46f47 RDX: 00007ffd60ed7970 RSI: 00007ffd60ed7a00 RDI: 00007ffd60ed7a00 RBP: 00007ffd60ed7a00 R08: 00007ffd60ed8a00 R09: 00000000ffffffff R10: 0000000000000100 R11: 0000000000000206 R12: 00007ffd60ed8af0 R13: 00007f5862cdd1ca R14: 0000000000039fc5 R15: 00007ffd60ed9bc0