EXT4-fs (loop8): orphan cleanup on readonly fs
==================================================================
BUG: KCSAN: data-race in data_alloc / prb_reserve

write to 0xffffffff8687d060 of 8 bytes by task 21300 on cpu 0:
 data_alloc+0x27d/0x2b0 kernel/printk/printk_ringbuffer.c:1096
 prb_reserve+0x808/0xaf0 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2326
 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2475
 __nla_validate_parse+0x1738/0x1d00 lib/nlattr.c:647
 __nla_parse+0x40/0x60 lib/nlattr.c:732
 __nlmsg_parse include/net/netlink.h:787 [inline]
 nlmsg_parse_deprecated include/net/netlink.h:828 [inline]
 rtnl_dellink+0xed/0x550 net/core/rtnetlink.c:3529
 rtnetlink_rcv_msg+0x5fe/0x6d0 net/core/rtnetlink.c:6944
 netlink_rcv_skb+0x120/0x220 net/netlink/af_netlink.c:2534
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6971
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x5a1/0x670 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x142/0x180 net/socket.c:727
 ____sys_sendmsg+0x31e/0x4e0 net/socket.c:2566
 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2620
 __sys_sendmsg net/socket.c:2652 [inline]
 __do_sys_sendmsg net/socket.c:2657 [inline]
 __se_sys_sendmsg net/socket.c:2655 [inline]
 __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2655
 x64_sys_call+0x2999/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff8687d060 of 8 bytes by task 21293 on cpu 1:
 desc_read kernel/printk/printk_ringbuffer.c:482 [inline]
 desc_push_tail kernel/printk/printk_ringbuffer.c:778 [inline]
 desc_reserve kernel/printk/printk_ringbuffer.c:924 [inline]
 prb_reserve+0x221/0xaf0 kernel/printk/printk_ringbuffer.c:1619
 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2326
 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2475
 __ext4_error+0x248/0x320 fs/ext4/super.c:813
 ext4_validate_block_bitmap+0x557/0x5a0 fs/ext4/balloc.c:-1
 ext4_read_block_bitmap_nowait+0x435/0x680 fs/ext4/balloc.c:557
 ext4_mb_init_cache+0x240/0xb70 fs/ext4/mballoc.c:1337
 ext4_mb_init_group+0x25b/0x3f0 fs/ext4/mballoc.c:1543
 ext4_mb_good_group_nolock fs/ext4/mballoc.c:2704 [inline]
 ext4_mb_regular_allocator+0xb1a/0x2300 fs/ext4/mballoc.c:2903
 ext4_mb_new_blocks+0x800/0x2050 fs/ext4/mballoc.c:6215
 ext4_ext_map_blocks+0xff5/0x38a0 fs/ext4/extents.c:4383
 ext4_map_create_blocks fs/ext4/inode.c:609 [inline]
 ext4_map_blocks+0x61c/0xd70 fs/ext4/inode.c:813
 ext4_getblk+0x114/0x510 fs/ext4/inode.c:960
 ext4_bread+0x28/0x110 fs/ext4/inode.c:1023
 ext4_quota_write+0x167/0x360 fs/ext4/super.c:7297
 write_blk+0x99/0x110 fs/quota/quota_tree.c:70
 do_insert_tree+0x7c3/0x9b0 fs/quota/quota_tree.c:407
 do_insert_tree+0x731/0x9b0 fs/quota/quota_tree.c:402
 do_insert_tree+0x731/0x9b0 fs/quota/quota_tree.c:402
 do_insert_tree+0x731/0x9b0 fs/quota/quota_tree.c:402
 dq_insert_tree fs/quota/quota_tree.c:432 [inline]
 qtree_write_dquot+0x2cb/0x300 fs/quota/quota_tree.c:451
 v2_write_dquot+0xda/0x140 fs/quota/quota_v2.c:372
 dquot_acquire+0x1c0/0x2b0 fs/quota/dquot.c:470
 ext4_acquire_dquot+0x15f/0x200 fs/ext4/super.c:6929
 dqget+0x532/0x8d0 fs/quota/dquot.c:977
 __dquot_initialize+0x20c/0x7c0 fs/quota/dquot.c:1505
 dquot_initialize+0x1a/0x30 fs/quota/dquot.c:1567
 ext4_process_orphan+0x32/0x1c0 fs/ext4/orphan.c:329
 ext4_orphan_cleanup+0x6a8/0xa00 fs/ext4/orphan.c:474
 __ext4_fill_super fs/ext4/super.c:5605 [inline]
 ext4_fill_super+0x3171/0x34e0 fs/ext4/super.c:5724
 get_tree_bdev_flags+0x291/0x300 fs/super.c:1679
 get_tree_bdev+0x1f/0x30 fs/super.c:1702
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5756
 vfs_get_tree+0x54/0x1d0 fs/super.c:1802
 do_new_mount+0x207/0x680 fs/namespace.c:3885
 path_mount+0x4a4/0xb20 fs/namespace.c:4209
 do_mount fs/namespace.c:4222 [inline]
 __do_sys_mount fs/namespace.c:4433 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4410
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4410
 x64_sys_call+0xd36/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000003570 -> 0x00000000000b3138

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 21293 Comm: syz.8.6002 Not tainted 6.16.0-rc1-syzkaller-00003-gf09079bd04a9 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================
EXT4-fs error (device loop8): ext4_validate_block_bitmap:441: comm syz.8.6002: bg 0: block 248: padding at end of block bitmap is not set
EXT4-fs error (device loop8): ext4_acquire_dquot:6933: comm syz.8.6002: Failed to acquire dquot type 1
EXT4-fs (loop8): 1 truncate cleaned up
EXT4-fs (loop8): mounted filesystem 00000000-0000-0000-0000-000000000000 ro without journal. Quota mode: writeback.
EXT4-fs (loop8): unmounting filesystem 00000000-0000-0000-0000-000000000000.