====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.2.627/6794 is trying to acquire lock: ffff888072574428 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:507 but task is already holding lock: ffff8880727d5cd0 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_truncate+0x999/0x1240 fs/ext4/inode.c:4290 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+0x910/0x1b70 fs/ext4/inode.c:672 ext4_getblk+0x1cc/0x6f0 fs/ext4/inode.c:890 ext4_bread+0x26/0x170 fs/ext4/inode.c:946 ext4_quota_write+0x236/0x580 fs/ext4/super.c:7222 write_blk fs/quota/quota_tree.c:70 [inline] find_free_dqentry+0x673/0xc20 fs/quota/quota_tree.c:318 do_insert_tree+0x70d/0x1040 fs/quota/quota_tree.c:400 do_insert_tree+0x9ae/0x1040 fs/quota/quota_tree.c:402 do_insert_tree+0x9ae/0x1040 fs/quota/quota_tree.c:402 do_insert_tree+0x9ae/0x1040 fs/quota/quota_tree.c:402 dq_insert_tree fs/quota/quota_tree.c:432 [inline] qtree_write_dquot+0x49d/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:472 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6831 dqget+0x778/0xeb0 fs/quota/dquot.c:988 __dquot_initialize+0x333/0xcd0 fs/quota/dquot.c:1517 ext4_mknod+0x97/0x4b0 fs/ext4/namei.c:2911 vfs_mknod+0x424/0x4c0 fs/namei.c:3993 do_mknodat+0x356/0x4d0 fs/namei.c:-1 __do_sys_mknod fs/namei.c:4076 [inline] __se_sys_mknod fs/namei.c:4074 [inline] __x64_sys_mknod+0x8a/0xa0 fs/namei.c:4074 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:463 ext4_acquire_dquot+0x2d9/0x4a0 fs/ext4/super.c:6831 dqget+0x778/0xeb0 fs/quota/dquot.c:988 __dquot_initialize+0x333/0xcd0 fs/quota/dquot.c:1517 ext4_mknod+0x97/0x4b0 fs/ext4/namei.c:2911 vfs_mknod+0x424/0x4c0 fs/namei.c:3993 do_mknodat+0x356/0x4d0 fs/namei.c:-1 __do_sys_mknod fs/namei.c:4076 [inline] __se_sys_mknod fs/namei.c:4074 [inline] __x64_sys_mknod+0x8a/0xa0 fs/namei.c:4074 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:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2d07/0x7d10 kernel/locking/lockdep.c:5049 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xaf0 kernel/locking/mutex.c:747 dquot_commit+0x5a/0x410 fs/quota/dquot.c:507 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6811 mark_dquot_dirty fs/quota/dquot.c:372 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:412 __dquot_free_space+0x7ec/0xbc0 fs/quota/dquot.c:1942 dquot_free_space_nodirty include/linux/quotaops.h:379 [inline] dquot_free_space include/linux/quotaops.h:384 [inline] dquot_free_block include/linux/quotaops.h:395 [inline] ext4_mb_clear_bb fs/ext4/mballoc.c:6154 [inline] ext4_free_blocks+0x1bf3/0x26a0 fs/ext4/mballoc.c:6284 ext4_remove_blocks fs/ext4/extents.c:2526 [inline] ext4_ext_rm_leaf fs/ext4/extents.c:2692 [inline] ext4_ext_remove_space+0x225f/0x44c0 fs/ext4/extents.c:2940 ext4_ext_truncate+0x211/0x370 fs/ext4/extents.c:4470 ext4_truncate+0xa23/0x1240 fs/ext4/inode.c:4295 ext4_evict_inode+0xb41/0x1110 fs/ext4/inode.c:286 evict+0x4c9/0x8d0 fs/inode.c:705 do_unlinkat+0x388/0x580 fs/namei.c:4405 __do_sys_unlinkat fs/namei.c:4441 [inline] __se_sys_unlinkat fs/namei.c:4434 [inline] __x64_sys_unlinkat+0xd1/0xe0 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 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.2.627/6794: #0: ffff88807c818460 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x3d/0x90 fs/namespace.c:402 #1: ffff88807c818650 (sb_internal){.+.+}-{0:0}, at: __sb_start_write include/linux/fs.h:1891 [inline] #1: ffff88807c818650 (sb_internal){.+.+}-{0:0}, at: sb_start_intwrite include/linux/fs.h:2013 [inline] #1: ffff88807c818650 (sb_internal){.+.+}-{0:0}, at: ext4_evict_inode+0x43c/0x1110 fs/ext4/inode.c:240 #2: ffff8880727d5cd0 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_truncate+0x999/0x1240 fs/ext4/inode.c:4290 #3: ffffffff8cc74988 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #3: ffffffff8cc74988 (dquot_srcu){....}-{0:0}, at: srcu_read_lock include/linux/srcu.h:165 [inline] #3: ffffffff8cc74988 (dquot_srcu){....}-{0:0}, at: __dquot_free_space+0x174/0xbc0 fs/quota/dquot.c:1915 stack backtrace: CPU: 1 PID: 6794 Comm: syz.2.627 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 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:3090 [inline] check_prevs_add kernel/locking/lockdep.c:3209 [inline] validate_chain kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2d07/0x7d10 kernel/locking/lockdep.c:5049 lock_acquire+0x1bb/0x4a0 kernel/locking/lockdep.c:5662 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12d/0xaf0 kernel/locking/mutex.c:747 dquot_commit+0x5a/0x410 fs/quota/dquot.c:507 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6811 mark_dquot_dirty fs/quota/dquot.c:372 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:412 __dquot_free_space+0x7ec/0xbc0 fs/quota/dquot.c:1942 dquot_free_space_nodirty include/linux/quotaops.h:379 [inline] dquot_free_space include/linux/quotaops.h:384 [inline] dquot_free_block include/linux/quotaops.h:395 [inline] ext4_mb_clear_bb fs/ext4/mballoc.c:6154 [inline] ext4_free_blocks+0x1bf3/0x26a0 fs/ext4/mballoc.c:6284 ext4_remove_blocks fs/ext4/extents.c:2526 [inline] ext4_ext_rm_leaf fs/ext4/extents.c:2692 [inline] ext4_ext_remove_space+0x225f/0x44c0 fs/ext4/extents.c:2940 ext4_ext_truncate+0x211/0x370 fs/ext4/extents.c:4470 ext4_truncate+0xa23/0x1240 fs/ext4/inode.c:4295 ext4_evict_inode+0xb41/0x1110 fs/ext4/inode.c:286 evict+0x4c9/0x8d0 fs/inode.c:705 do_unlinkat+0x388/0x580 fs/namei.c:4405 __do_sys_unlinkat fs/namei.c:4441 [inline] __se_sys_unlinkat fs/namei.c:4434 [inline] __x64_sys_unlinkat+0xd1/0xe0 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 RIP: 0033:0x7f074299aeb9 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:00007f0743795028 EFLAGS: 00000246 ORIG_RAX: 0000000000000107 RAX: ffffffffffffffda RBX: 00007f0742c15fa0 RCX: 00007f074299aeb9 RDX: 0000000000000000 RSI: 0000200000000c40 RDI: ffffffffffffff9c RBP: 00007f0742a08c1f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0742c16038 R14: 00007f0742c15fa0 R15: 00007ffec28eb478 EXT4-fs (loop2): unmounting filesystem.