====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.0.340/5765 is trying to acquire lock: ffff888054754428 (&dquot->dq_lock){+.+.}-{3:3}, at: dquot_commit+0x5a/0x410 fs/quota/dquot.c:507 but task is already holding lock: ffff8880596cdcd0 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x903/0x1b60 fs/ext4/inode.c:672 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+0x903/0x1b60 fs/ext4/inode.c:672 ext4_getblk+0x1ab/0x6d0 fs/ext4/inode.c:890 ext4_bread+0x26/0x170 fs/ext4/inode.c:946 ext4_quota_write+0x230/0x570 fs/ext4/super.c:7203 write_blk fs/quota/quota_tree.c:70 [inline] get_free_dqblk+0x312/0x660 fs/quota/quota_tree.c:136 do_insert_tree+0x22b/0x1040 fs/quota/quota_tree.c:347 do_insert_tree+0x9eb/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+0x48d/0x5b0 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:6812 dqget+0x778/0xeb0 fs/quota/dquot.c:988 __dquot_initialize+0x328/0xcb0 fs/quota/dquot.c:1517 ext4_xattr_set+0xbd/0x320 fs/ext4/xattr.c:2499 __vfs_setxattr+0x3e0/0x420 fs/xattr.c:182 __vfs_setxattr_noperm+0x129/0x5e0 fs/xattr.c:216 vfs_setxattr+0x168/0x2f0 fs/xattr.c:309 do_setxattr fs/xattr.c:594 [inline] setxattr+0x2b2/0x2d0 fs/xattr.c:617 path_setxattr+0x142/0x280 fs/xattr.c:636 __do_sys_setxattr fs/xattr.c:652 [inline] __se_sys_setxattr fs/xattr.c:648 [inline] __x64_sys_setxattr+0xb7/0xd0 fs/xattr.c:648 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 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:6812 dqget+0x778/0xeb0 fs/quota/dquot.c:988 __dquot_initialize+0x328/0xcb0 fs/quota/dquot.c:1517 ext4_xattr_set+0xbd/0x320 fs/ext4/xattr.c:2499 __vfs_setxattr+0x3e0/0x420 fs/xattr.c:182 __vfs_setxattr_noperm+0x129/0x5e0 fs/xattr.c:216 vfs_setxattr+0x168/0x2f0 fs/xattr.c:309 do_setxattr fs/xattr.c:594 [inline] setxattr+0x2b2/0x2d0 fs/xattr.c:617 path_setxattr+0x142/0x280 fs/xattr.c:636 __do_sys_setxattr fs/xattr.c:652 [inline] __se_sys_setxattr fs/xattr.c:648 [inline] __x64_sys_setxattr+0xb7/0xd0 fs/xattr.c:648 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 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 kernel/locking/lockdep.c:3825 [inline] __lock_acquire+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747 dquot_commit+0x5a/0x410 fs/quota/dquot.c:507 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6792 mark_dquot_dirty fs/quota/dquot.c:372 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:412 __dquot_alloc_space+0x5fc/0xe60 fs/quota/dquot.c:1752 dquot_alloc_space_nodirty include/linux/quotaops.h:300 [inline] dquot_alloc_space include/linux/quotaops.h:313 [inline] dquot_alloc_block include/linux/quotaops.h:337 [inline] ext4_mb_new_blocks+0xf74/0x4720 fs/ext4/mballoc.c:5722 ext4_ext_map_blocks+0x143c/0x66d0 fs/ext4/extents.c:4340 ext4_map_blocks+0x9d1/0x1b60 fs/ext4/inode.c:679 ext4_iomap_alloc fs/ext4/inode.c:3438 [inline] ext4_iomap_begin+0x7d2/0xae0 fs/ext4/inode.c:3488 iomap_iter+0x6c6/0x1040 fs/iomap/iter.c:91 __iomap_dio_rw+0xcba/0x1dd0 fs/iomap/direct-io.c:601 iomap_dio_rw+0x41/0xa0 fs/iomap/direct-io.c:690 ext4_dio_write_iter fs/ext4/file.c:557 [inline] ext4_file_write_iter+0x1262/0x16e0 fs/ext4/file.c:677 do_iter_readv_writev fs/read_write.c:-1 [inline] do_iter_write+0x62d/0xaf0 fs/read_write.c:861 iter_file_splice_write+0x665/0xc50 fs/splice.c:685 do_splice_from fs/splice.c:763 [inline] direct_splice_actor+0xe1/0x130 fs/splice.c:950 splice_direct_to_actor+0x480/0xb60 fs/splice.c:896 do_splice_direct+0x1b0/0x2b0 fs/splice.c:1002 do_sendfile+0x5cc/0xeb0 fs/read_write.c:1255 __do_sys_sendfile64 fs/read_write.c:1323 [inline] __se_sys_sendfile64+0x13b/0x190 fs/read_write.c:1309 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 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 --> &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.0.340/5765: #0: ffff888076e82460 (sb_writers#4){.+.+}-{0:0}, at: do_sendfile+0x5a9/0xeb0 fs/read_write.c:1254 #1: ffff8880596cde48 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: inode_lock include/linux/fs.h:758 [inline] #1: ffff8880596cde48 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_dio_write_checks fs/ext4/file.c:439 [inline] #1: ffff8880596cde48 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_dio_write_iter fs/ext4/file.c:507 [inline] #1: ffff8880596cde48 (&sb->s_type->i_mutex_key#8){++++}-{3:3}, at: ext4_file_write_iter+0xb55/0x16e0 fs/ext4/file.c:677 #2: ffff8880596cdcd0 (&ei->i_data_sem/2){++++}-{3:3}, at: ext4_map_blocks+0x903/0x1b60 fs/ext4/inode.c:672 #3: ffffffff8cc72c48 (dquot_srcu){....}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #3: ffffffff8cc72c48 (dquot_srcu){....}-{0:0}, at: srcu_read_lock include/linux/srcu.h:165 [inline] #3: ffffffff8cc72c48 (dquot_srcu){....}-{0:0}, at: __dquot_alloc_space+0x173/0xe60 fs/quota/dquot.c:1716 stack backtrace: CPU: 0 PID: 5765 Comm: syz.0.340 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106 check_noncircular+0x274/0x310 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+0x2cf8/0x7c50 kernel/locking/lockdep.c:5049 lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662 __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x120/0xaf0 kernel/locking/mutex.c:747 dquot_commit+0x5a/0x410 fs/quota/dquot.c:507 ext4_write_dquot+0x1f0/0x360 fs/ext4/super.c:6792 mark_dquot_dirty fs/quota/dquot.c:372 [inline] mark_all_dquot_dirty+0xf9/0x400 fs/quota/dquot.c:412 __dquot_alloc_space+0x5fc/0xe60 fs/quota/dquot.c:1752 dquot_alloc_space_nodirty include/linux/quotaops.h:300 [inline] dquot_alloc_space include/linux/quotaops.h:313 [inline] dquot_alloc_block include/linux/quotaops.h:337 [inline] ext4_mb_new_blocks+0xf74/0x4720 fs/ext4/mballoc.c:5722 ext4_ext_map_blocks+0x143c/0x66d0 fs/ext4/extents.c:4340 ext4_map_blocks+0x9d1/0x1b60 fs/ext4/inode.c:679 ext4_iomap_alloc fs/ext4/inode.c:3438 [inline] ext4_iomap_begin+0x7d2/0xae0 fs/ext4/inode.c:3488 iomap_iter+0x6c6/0x1040 fs/iomap/iter.c:91 __iomap_dio_rw+0xcba/0x1dd0 fs/iomap/direct-io.c:601 iomap_dio_rw+0x41/0xa0 fs/iomap/direct-io.c:690 ext4_dio_write_iter fs/ext4/file.c:557 [inline] ext4_file_write_iter+0x1262/0x16e0 fs/ext4/file.c:677 do_iter_readv_writev fs/read_write.c:-1 [inline] do_iter_write+0x62d/0xaf0 fs/read_write.c:861 iter_file_splice_write+0x665/0xc50 fs/splice.c:685 do_splice_from fs/splice.c:763 [inline] direct_splice_actor+0xe1/0x130 fs/splice.c:950 splice_direct_to_actor+0x480/0xb60 fs/splice.c:896 do_splice_direct+0x1b0/0x2b0 fs/splice.c:1002 do_sendfile+0x5cc/0xeb0 fs/read_write.c:1255 __do_sys_sendfile64 fs/read_write.c:1323 [inline] __se_sys_sendfile64+0x13b/0x190 fs/read_write.c:1309 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fe9a958ebe9 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:00007fe9aa40f038 EFLAGS: 00000246 ORIG_RAX: 0000000000000028 RAX: ffffffffffffffda RBX: 00007fe9a97c6180 RCX: 00007fe9a958ebe9 RDX: 0000000000000000 RSI: 000000000000000a RDI: 000000000000000a RBP: 00007fe9a9611e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000800000009 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe9a97c6218 R14: 00007fe9a97c6180 R15: 00007ffc55f71d48