possible deadlock in dqget

Kernel	Title	Rank 🛈	Repro	Cause bisect	Count	Last	Reported	Patched	Status
linux-6.6	possible deadlock in dqget	4			27	20h37m	222d	0/2	upstream: reported on 2025/06/20 12:37
upstream	possible deadlock in dqget ocfs2 ext4	4	C	error	100357	31d	485d	29/29	fixed on 2026/01/07 12:29
linux-5.15	possible deadlock in dqget	4			1	5d14h	5d14h	0/3	upstream: reported on 2026/01/23 21:59
upstream	possible deadlock in dqget (2) fs	4			1	9d11h	5d11h	0/29	upstream: reported on 2026/01/24 00:53
linux-6.1	possible deadlock in dqget (2)	4			11	98d	212d	0/3	upstream: reported on 2025/06/30 17:34

====================================================== WARNING: possible circular locking dependency detected 6.1.127-syzkaller #0 Not tainted ------------------------------------------------------ syz.3.11280/30035 is trying to acquire lock: ffff888052ddfca8 (&dquot->dq_lock){+.+.}-{3:3}, at: wait_on_dquot fs/quota/dquot.c:356 [inline] ffff888052ddfca8 (&dquot->dq_lock){+.+.}-{3:3}, at: dqget+0x6dc/0xe90 fs/quota/dquot.c:983 but task is already holding lock: ffff888052e2b2f0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_setattr+0xbbb/0x1a00 fs/ext4/inode.c:5471 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #5 (&ei->xattr_sem){++++}-{3:3}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 down_read+0xad/0xa30 kernel/locking/rwsem.c:1520 ext4_setattr+0xbbb/0x1a00 fs/ext4/inode.c:5471 notify_change+0xce3/0xfc0 fs/attr.c:499 chown_common+0x5aa/0x900 fs/open.c:736 do_fchownat+0x169/0x240 fs/open.c:767 __do_sys_chown fs/open.c:787 [inline] __se_sys_chown fs/open.c:785 [inline] __x64_sys_chown+0x7e/0x90 fs/open.c:785 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #4 (jbd2_handle){++++}-{0:0}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 start_this_handle+0x1f71/0x21b0 fs/jbd2/transaction.c:463 jbd2__journal_start+0x2d1/0x5c0 fs/jbd2/transaction.c:520 jbd2_journal_start+0x25/0x30 fs/jbd2/transaction.c:559 ocfs2_start_trans+0x3c0/0x6f0 fs/ocfs2/journal.c:354 ocfs2_shutdown_local_alloc+0x214/0xa90 fs/ocfs2/localalloc.c:416 ocfs2_dismount_volume+0x1fb/0x960 fs/ocfs2/super.c:1879 generic_shutdown_super+0x130/0x340 fs/super.c:501 kill_block_super+0x7a/0xe0 fs/super.c:1470 deactivate_locked_super+0xa0/0x110 fs/super.c:332 cleanup_mnt+0x490/0x520 fs/namespace.c:1186 task_work_run+0x246/0x300 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #3 (&journal->j_trans_barrier){.+.+}-{3:3}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 down_read+0xad/0xa30 kernel/locking/rwsem.c:1520 ocfs2_start_trans+0x3b5/0x6f0 fs/ocfs2/journal.c:352 ocfs2_shutdown_local_alloc+0x214/0xa90 fs/ocfs2/localalloc.c:416 ocfs2_dismount_volume+0x1fb/0x960 fs/ocfs2/super.c:1879 generic_shutdown_super+0x130/0x340 fs/super.c:501 kill_block_super+0x7a/0xe0 fs/super.c:1470 deactivate_locked_super+0xa0/0x110 fs/super.c:332 cleanup_mnt+0x490/0x520 fs/namespace.c:1186 task_work_run+0x246/0x300 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #2 (sb_internal#2){.+.+}-{0:0}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 percpu_down_read include/linux/percpu-rwsem.h:51 [inline] __sb_start_write include/linux/fs.h:1891 [inline] sb_start_intwrite include/linux/fs.h:2013 [inline] ocfs2_start_trans+0x2b0/0x6f0 fs/ocfs2/journal.c:350 ocfs2_acquire_dquot+0x68c/0xb60 fs/ocfs2/quota_global.c:843 dqget+0x762/0xe90 fs/quota/dquot.c:988 __dquot_initialize+0x2d9/0xea0 fs/quota/dquot.c:1517 ocfs2_get_init_inode+0x154/0x1c0 fs/ocfs2/namei.c:202 ocfs2_mknod+0xe32/0x2e20 fs/ocfs2/namei.c:310 ocfs2_mkdir+0x1c0/0x4e0 fs/ocfs2/namei.c:657 vfs_mkdir+0x3b6/0x590 fs/namei.c:4106 do_mkdirat+0x225/0x360 fs/namei.c:4131 __do_sys_mkdirat fs/namei.c:4146 [inline] __se_sys_mkdirat fs/namei.c:4144 [inline] __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4144 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #1 (&ocfs2_quota_ip_alloc_sem_key){++++}-{3:3}: lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 down_write+0x36/0x60 kernel/locking/rwsem.c:1573 ocfs2_create_local_dquot+0x1dc/0x1b50 fs/ocfs2/quota_local.c:1229 ocfs2_acquire_dquot+0x7df/0xb60 fs/ocfs2/quota_global.c:866 dqget+0x762/0xe90 fs/quota/dquot.c:988 __dquot_initialize+0x2d9/0xea0 fs/quota/dquot.c:1517 ocfs2_get_init_inode+0x154/0x1c0 fs/ocfs2/namei.c:202 ocfs2_mknod+0xe32/0x2e20 fs/ocfs2/namei.c:310 ocfs2_mkdir+0x1c0/0x4e0 fs/ocfs2/namei.c:657 vfs_mkdir+0x3b6/0x590 fs/namei.c:4106 do_mkdirat+0x225/0x360 fs/namei.c:4131 __do_sys_mkdirat fs/namei.c:4146 [inline] __se_sys_mkdirat fs/namei.c:4144 [inline] __x64_sys_mkdirat+0x85/0x90 fs/namei.c:4144 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 -> #0 (&dquot->dq_lock){+.+.}-{3:3}: check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747 wait_on_dquot fs/quota/dquot.c:356 [inline] dqget+0x6dc/0xe90 fs/quota/dquot.c:983 dquot_transfer+0x3a1/0x8a0 fs/quota/dquot.c:2150 ext4_setattr+0xbd3/0x1a00 fs/ext4/inode.c:5472 notify_change+0xce3/0xfc0 fs/attr.c:499 chown_common+0x5aa/0x900 fs/open.c:736 do_fchownat+0x169/0x240 fs/open.c:767 __do_sys_lchown fs/open.c:792 [inline] __se_sys_lchown fs/open.c:790 [inline] __x64_sys_lchown+0x81/0x90 fs/open.c:790 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 other info that might help us debug this: Chain exists of: &dquot->dq_lock --> jbd2_handle --> &ei->xattr_sem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&ei->xattr_sem); lock(jbd2_handle); lock(&ei->xattr_sem); lock(&dquot->dq_lock); *** DEADLOCK *** 3 locks held by syz.3.11280/30035: #0: ffff88804b410460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3b/0x80 fs/namespace.c:393 #1: ffff888052e2b628 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #1: ffff888052e2b628 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: chown_common+0x3e5/0x900 fs/open.c:726 #2: ffff888052e2b2f0 (&ei->xattr_sem){++++}-{3:3}, at: ext4_setattr+0xbbb/0x1a00 fs/ext4/inode.c:5471 stack backtrace: CPU: 0 PID: 30035 Comm: syz.3.11280 Not tainted 6.1.127-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 check_noncircular+0x2fa/0x3b0 kernel/locking/lockdep.c:2170 check_prev_add kernel/locking/lockdep.c:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain+0x1661/0x5950 kernel/locking/lockdep.c:3825 __lock_acquire+0x125b/0x1f80 kernel/locking/lockdep.c:5049 lock_acquire+0x1f8/0x5a0 kernel/locking/lockdep.c:5662 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x132/0xd80 kernel/locking/mutex.c:747 wait_on_dquot fs/quota/dquot.c:356 [inline] dqget+0x6dc/0xe90 fs/quota/dquot.c:983 dquot_transfer+0x3a1/0x8a0 fs/quota/dquot.c:2150 ext4_setattr+0xbd3/0x1a00 fs/ext4/inode.c:5472 notify_change+0xce3/0xfc0 fs/attr.c:499 chown_common+0x5aa/0x900 fs/open.c:736 do_fchownat+0x169/0x240 fs/open.c:767 __do_sys_lchown fs/open.c:792 [inline] __se_sys_lchown fs/open.c:790 [inline] __x64_sys_lchown+0x81/0x90 fs/open.c:790 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fba1b18cd29 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fba1bf0d038 EFLAGS: 00000246 ORIG_RAX: 000000000000005e RAX: ffffffffffffffda RBX: 00007fba1b3a5fa0 RCX: 00007fba1b18cd29 RDX: ffffffffffffffff RSI: 000000000000ee00 RDI: 0000000020000140 RBP: 00007fba1b20e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fba1b3a5fa0 R15: 00007ffe4df15768 </TASK>

Crashes (1):
Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Assets (help?)	Manager	Title
2025/01/27 22:19	linux-6.1.y	75cefdf153f5	18070896	.config	console log	report			info	[disk image] [vmlinux] [kernel image]	ci2-linux-6-1-kasan	possible deadlock in dqget

Crashes (1):

Assets (help?)