loop2: detected capacity change from 0 to 4096 EXT4-fs (loop2): mounted filesystem without journal. Quota mode: writeback. ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.1342/8809 is trying to acquire lock: ffff88807246c268 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:535 but task is already holding lock: ffff888054e2beb8 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x914/0x1a90 fs/ext4/inode.c:674 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&ei->i_data_sem/2){++++}-{3:3}: 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:7223 write_blk fs/quota/quota_tree.c:70 [inline] find_free_dqentry+0x68c/0xc30 fs/quota/quota_tree.c:318 do_insert_tree+0x717/0x1060 fs/quota/quota_tree.c:400 do_insert_tree+0x9b8/0x1060 fs/quota/quota_tree.c:402 do_insert_tree+0x9b8/0x1060 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:6844 dqget+0x713/0xbb0 fs/quota/dquot.c:1013 __dquot_initialize+0x324/0xd00 fs/quota/dquot.c:1542 ext4_file_open+0x2da/0x6f0 fs/ext4/file.c:876 do_dentry_open+0x7dd/0x10b0 fs/open.c:882 do_open fs/namei.c:3677 [inline] path_openat+0x2674/0x2f10 fs/namei.c:3838 do_filp_open+0x1ee/0x420 fs/namei.c:3865 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 (&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:6844 dqget+0x713/0xbb0 fs/quota/dquot.c:1013 __dquot_initialize+0x324/0xd00 fs/quota/dquot.c:1542 ext4_file_open+0x2da/0x6f0 fs/ext4/file.c:876 do_dentry_open+0x7dd/0x10b0 fs/open.c:882 do_open fs/namei.c:3677 [inline] path_openat+0x2674/0x2f10 fs/namei.c:3838 do_filp_open+0x1ee/0x420 fs/namei.c:3865 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 -> #0 (&dquot->dq_lock){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3162 [inline] check_prevs_add kernel/locking/lockdep.c:3281 [inline] validate_chain kernel/locking/lockdep.c:3897 [inline] __lock_acquire+0x3a03/0x7ea0 kernel/locking/lockdep.c:5171 lock_acquire+0x1bc/0x4a0 kernel/locking/lockdep.c:5790 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xb40 kernel/locking/mutex.c:747 dquot_commit+0x5a/0x410 fs/quota/dquot.c:535 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6824 mark_dquot_dirty fs/quota/dquot.c:400 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:440 __dquot_alloc_space+0x5f6/0xe50 fs/quota/dquot.c:1777 dquot_alloc_space_nodirty include/linux/quotaops.h:293 [inline] dquot_alloc_space include/linux/quotaops.h:306 [inline] dquot_alloc_block include/linux/quotaops.h:330 [inline] ext4_mb_new_blocks+0xf55/0x44d0 fs/ext4/mballoc.c:5755 ext4_ext_map_blocks+0x184a/0x6680 fs/ext4/extents.c:4369 ext4_map_blocks+0x9d7/0x1a90 fs/ext4/inode.c:681 ext4_getblk+0x1c5/0x720 fs/ext4/inode.c:892 ext4_bread+0x26/0x170 fs/ext4/inode.c:948 ext4_init_symlink_block fs/ext4/namei.c:3396 [inline] ext4_symlink+0x515/0x940 fs/ext4/namei.c:3473 vfs_symlink+0x245/0x3d0 fs/namei.c:4526 do_symlinkat+0x1b6/0x400 fs/namei.c:4555 __do_sys_symlinkat fs/namei.c:4572 [inline] __se_sys_symlinkat fs/namei.c:4569 [inline] __x64_sys_symlinkat+0x95/0xa0 fs/namei.c:4569 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: &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.2.1342/8809: #0: ffff8880238ac460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402 #1: ffff888054e2ac20 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: inode_lock_nested include/linux/fs.h:799 [inline] #1: ffff888054e2ac20 (&type->i_mutex_dir_key#3/1){+.+.}-{3:3}, at: filename_create+0x20b/0x450 fs/namei.c:3931 #2: ffff888054e2beb8 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x914/0x1a90 fs/ext4/inode.c:674 #3: ffffffff8dc750c8 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #3: ffffffff8dc750c8 (dquot_srcu){....}-{0:0}, at: srcu_read_lock include/linux/srcu.h:165 [inline] #3: ffffffff8dc750c8 (dquot_srcu){....}-{0:0}, at: __dquot_alloc_space+0x16e/0xe50 fs/quota/dquot.c:1741 stack backtrace: CPU: 1 PID: 8809 Comm: syz.2.1342 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Call Trace: dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106 check_noncircular+0x2f8/0x400 kernel/locking/lockdep.c:2215 check_prev_add kernel/locking/lockdep.c:3162 [inline] check_prevs_add kernel/locking/lockdep.c:3281 [inline] validate_chain kernel/locking/lockdep.c:3897 [inline] __lock_acquire+0x3a03/0x7ea0 kernel/locking/lockdep.c:5171 lock_acquire+0x1bc/0x4a0 kernel/locking/lockdep.c:5790 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xb40 kernel/locking/mutex.c:747 dquot_commit+0x5a/0x410 fs/quota/dquot.c:535 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6824 mark_dquot_dirty fs/quota/dquot.c:400 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:440 __dquot_alloc_space+0x5f6/0xe50 fs/quota/dquot.c:1777 dquot_alloc_space_nodirty include/linux/quotaops.h:293 [inline] dquot_alloc_space include/linux/quotaops.h:306 [inline] dquot_alloc_block include/linux/quotaops.h:330 [inline] ext4_mb_new_blocks+0xf55/0x44d0 fs/ext4/mballoc.c:5755 ext4_ext_map_blocks+0x184a/0x6680 fs/ext4/extents.c:4369 ext4_map_blocks+0x9d7/0x1a90 fs/ext4/inode.c:681 ext4_getblk+0x1c5/0x720 fs/ext4/inode.c:892 ext4_bread+0x26/0x170 fs/ext4/inode.c:948 ext4_init_symlink_block fs/ext4/namei.c:3396 [inline] ext4_symlink+0x515/0x940 fs/ext4/namei.c:3473 vfs_symlink+0x245/0x3d0 fs/namei.c:4526 do_symlinkat+0x1b6/0x400 fs/namei.c:4555 __do_sys_symlinkat fs/namei.c:4572 [inline] __se_sys_symlinkat fs/namei.c:4569 [inline] __x64_sys_symlinkat+0x95/0xa0 fs/namei.c:4569 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: 0033:0x7efc5799fb19 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:00007efc587d6028 EFLAGS: 00000246 ORIG_RAX: 000000000000010a RAX: ffffffffffffffda RBX: 00007efc57c25fa0 RCX: 00007efc5799fb19 RDX: 00002000000005c0 RSI: ffffffffffffff9c RDI: 0000200000000700 RBP: 00007efc57a37af8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007efc57c26038 R14: 00007efc57c25fa0 R15: 00007ffe557dec38