EXT4-fs (loop2): mounted filesystem without journal. Opts: grpquota,,errors=continue. Quota mode: writeback. ====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.1950/12366 is trying to acquire lock: ffff88805ec865e8 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:507 but task is already holding lock: ffff88805ec93e48 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x8bf/0x1b30 fs/ext4/inode.c:666 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_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_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+0x3c3/0xcd0 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_creat fs/open.c:1347 [inline] __se_sys_creat fs/open.c:1341 [inline] __x64_sys_creat+0x8c/0xb0 fs/open.c:1341 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 (&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_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_creat fs/open.c:1347 [inline] __se_sys_creat fs/open.c:1341 [inline] __x64_sys_creat+0x8c/0xb0 fs/open.c:1341 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 (&dquot->dq_lock){+.+.}-{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 __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_get_block+0x1e7/0x540 fs/ext4/inode.c:816 ext4_block_write_begin+0x61b/0x1220 fs/ext4/inode.c:1101 ext4_write_begin+0x6c8/0x15d0 fs/ext4/ext4_jbd2.h:-1 ext4_da_write_begin+0x43b/0xb40 fs/ext4/inode.c:2975 generic_perform_write+0x2b6/0x550 mm/filemap.c:3785 ext4_buffered_write_iter+0x25f/0x3b0 fs/ext4/file.c:268 ext4_file_write_iter+0x74d/0x1700 fs/ext4/file.c:-1 call_write_iter include/linux/fs.h:2173 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x745/0xd60 fs/read_write.c:594 ksys_write+0x152/0x260 fs/read_write.c:647 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: &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 *** 5 locks held by syz.2.1950/12366: #0: ffff88802807aff0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x2bf/0x370 fs/file.c:1056 #1: ffff8880797da460 (sb_writers#5){.+.+}-{0:0}, at: vfs_write+0x295/0xd60 fs/read_write.c:590 #2: ffff88805ec93fc0 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: inode_lock include/linux/fs.h:787 [inline] #2: ffff88805ec93fc0 (&sb->s_type->i_mutex_key#9){++++}-{3:3}, at: ext4_buffered_write_iter+0xa6/0x3b0 fs/ext4/file.c:262 #3: ffff88805ec93e48 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x8bf/0x1b30 fs/ext4/inode.c:666 #4: ffffffff8c441538 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:312 stack backtrace: CPU: 0 PID: 12366 Comm: syz.2.1950 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 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 __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_get_block+0x1e7/0x540 fs/ext4/inode.c:816 ext4_block_write_begin+0x61b/0x1220 fs/ext4/inode.c:1101 ext4_write_begin+0x6c8/0x15d0 fs/ext4/ext4_jbd2.h:-1 ext4_da_write_begin+0x43b/0xb40 fs/ext4/inode.c:2975 generic_perform_write+0x2b6/0x550 mm/filemap.c:3785 ext4_buffered_write_iter+0x25f/0x3b0 fs/ext4/file.c:268 ext4_file_write_iter+0x74d/0x1700 fs/ext4/file.c:-1 call_write_iter include/linux/fs.h:2173 [inline] new_sync_write fs/read_write.c:507 [inline] vfs_write+0x745/0xd60 fs/read_write.c:594 ksys_write+0x152/0x260 fs/read_write.c:647 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: 0033:0x7fc1d7d12629 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:00007fc1d5f6c028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fc1d7f8bfa0 RCX: 00007fc1d7d12629 RDX: 0000000000000014 RSI: 0000200000000000 RDI: 0000000000000008 RBP: 00007fc1d7da8b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc1d7f8c038 R14: 00007fc1d7f8bfa0 R15: 00007ffe22f97558