EXT4-fs error (device loop4): ext4_mb_generate_buddy:1217: group 0, 
==================================================================
BUG: KCSAN: data-race in data_push_tail / vsnprintf

write to 0xffffffff870f6dae of 1 bytes by task 32174 on cpu 0:
 vsnprintf+0xdd0/0xe20
 vscnprintf+0x42/0x80 lib/vsprintf.c:2930
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2124
 vprintk_store+0x56f/0x800 kernel/printk/printk.c:2238
 vprintk_emit+0xd0/0x5d0 kernel/printk/printk.c:2284
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2318
 vprintk+0x71/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2328
 p9_fd_create+0x1fb/0x260 net/9p/trans_fd.c:1099
 p9_client_create+0x595/0xa70 net/9p/client.c:1012
 v9fs_session_init+0xf9/0xd90 fs/9p/v9fs.c:410
 v9fs_mount+0x69/0x630 fs/9p/vfs_super.c:123
 legacy_get_tree+0x74/0xd0 fs/fs_context.c:662
 vfs_get_tree+0x51/0x1b0 fs/super.c:1784
 do_new_mount+0x227/0x690 fs/namespace.c:3352
 path_mount+0x496/0xb30 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3875
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3875
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x59/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffffffff870f6da8 of 8 bytes by task 32157 on cpu 1:
 data_make_reusable kernel/printk/printk_ringbuffer.c:590 [inline]
 data_push_tail+0x102/0x430 kernel/printk/printk_ringbuffer.c:675
 data_alloc+0xbe/0x2c0 kernel/printk/printk_ringbuffer.c:1046
 prb_reserve+0x893/0xbc0 kernel/printk/printk_ringbuffer.c:1555
 vprintk_store+0x53e/0x800 kernel/printk/printk.c:2228
 vprintk_emit+0xd0/0x5d0 kernel/printk/printk.c:2284
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2318
 vprintk+0x71/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2328
 __ext4_grp_locked_error+0x52a/0x780 fs/ext4/super.c:1072
 ext4_mb_generate_buddy+0x3d2/0x460 fs/ext4/mballoc.c:1214
 ext4_mb_init_cache+0x933/0xcc0 fs/ext4/mballoc.c:1384
 ext4_mb_init_group+0x1c4/0x5d0 fs/ext4/mballoc.c:1519
 ext4_mb_good_group_nolock fs/ext4/mballoc.c:2667 [inline]
 ext4_mb_regular_allocator+0xa7f/0x2390 fs/ext4/mballoc.c:2865
 ext4_mb_new_blocks+0x801/0x21e0 fs/ext4/mballoc.c:6190
 ext4_new_meta_blocks+0xc1/0x1a0 fs/ext4/balloc.c:750
 ext4_xattr_block_set+0x1052/0x1be0 fs/ext4/xattr.c:2143
 ext4_xattr_move_to_block fs/ext4/xattr.c:2667 [inline]
 ext4_xattr_make_inode_space fs/ext4/xattr.c:2742 [inline]
 ext4_expand_extra_isize_ea+0xa80/0x1110 fs/ext4/xattr.c:2834
 __ext4_expand_extra_isize+0x23f/0x280 fs/ext4/inode.c:5819
 ext4_try_to_expand_extra_isize fs/ext4/inode.c:5862 [inline]
 __ext4_mark_inode_dirty+0x2c5/0x440 fs/ext4/inode.c:5940
 ext4_inline_data_truncate+0x4d2/0x6b0 fs/ext4/inline.c:1994
 ext4_truncate+0x2f0/0xb10 fs/ext4/inode.c:4132
 ext4_process_orphan+0x113/0x1c0 fs/ext4/orphan.c:339
 ext4_orphan_cleanup+0x669/0x9b0 fs/ext4/orphan.c:474
 __ext4_fill_super fs/ext4/super.c:5582 [inline]
 ext4_fill_super+0x3660/0x39a0 fs/ext4/super.c:5703
 get_tree_bdev+0x250/0x2d0 fs/super.c:1619
 ext4_get_tree+0x1c/0x20 fs/ext4/super.c:5735
 vfs_get_tree+0x51/0x1b0 fs/super.c:1784
 do_new_mount+0x227/0x690 fs/namespace.c:3352
 path_mount+0x496/0xb30 fs/namespace.c:3679
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3875
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3875
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x59/0x120 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0000000100013e04 -> 0x00000a64663d6f74

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 32157 Comm: syz-executor.4 Not tainted 6.8.0-rc1-syzkaller-00037-g443b349019f2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
==================================================================
block bitmap and bg descriptor inconsistent: 191 vs 220 free clusters
EXT4-fs (loop4): 1 truncate cleaned up
EXT4-fs (loop4): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.
syz-executor.4 (32157) used greatest stack depth: 7936 bytes left