EXT4-fs (loop4): ext4_check_descriptors: Block bitmap for group 0 overlaps superblock
EXT4-fs (loop4): revision level too high, forcing read-only mode
==================================================================
BUG: KCSAN: data-race in data_push_tail / vsnprintf

write to 0xffffffff88e34800 of 9 bytes by task 9316 on cpu 0:
 vsnprintf+0x2ce/0x890 lib/vsprintf.c:2878
 va_format lib/vsprintf.c:1728 [inline]
 pointer+0x833/0xcf0 lib/vsprintf.c:2548
 vsnprintf+0x491/0x890 lib/vsprintf.c:2930
 vscnprintf+0x41/0x90 lib/vsprintf.c:2991
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2216
 vprintk_store+0x599/0x860 kernel/printk/printk.c:2336
 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_warning+0x12b/0x140 fs/ext4/super.c:1006
 __ext4_read_dirblock+0xe4/0x4f0 fs/ext4/namei.c:146
 ext4_empty_dir+0x143/0x600 fs/ext4/namei.c:3080
 ext4_rmdir+0x1df/0x640 fs/ext4/namei.c:3166
 vfs_rmdir+0x279/0x330 fs/namei.c:4461
 do_rmdir+0x178/0x440 fs/namei.c:4516
 __do_sys_unlinkat fs/namei.c:4690 [inline]
 __se_sys_unlinkat fs/namei.c:4684 [inline]
 __x64_sys_unlinkat+0x86/0xb0 fs/namei.c:4684
 x64_sys_call+0x2ede/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:264
 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 0xffffffff88e34800 of 8 bytes by task 17896 on cpu 1:
 data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline]
 data_push_tail+0xfd/0x420 kernel/printk/printk_ringbuffer.c:679
 data_alloc+0xbf/0x2b0 kernel/printk/printk_ringbuffer.c:1054
 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
 __ext4_msg+0x18f/0x1a0 fs/ext4/super.c:981
 ext4_setup_super+0x6b/0x580 fs/ext4/super.c:3067
 __ext4_fill_super fs/ext4/super.c:5526 [inline]
 ext4_fill_super+0x28b9/0x35d0 fs/ext4/super.c:5728
 get_tree_bdev_flags+0x28e/0x300 fs/super.c:1692
 get_tree_bdev+0x1f/0x30 fs/super.c:1715
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5760
 vfs_get_tree+0x57/0x1d0 fs/super.c:1815
 do_new_mount+0x207/0x5e0 fs/namespace.c:3808
 path_mount+0x4a4/0xb20 fs/namespace.c:4123
 do_mount fs/namespace.c:4136 [inline]
 __do_sys_mount fs/namespace.c:4347 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4324
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4324
 x64_sys_call+0x2b4d/0x2ff0 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: 0x00000000fffffb59 -> 0x30206b636f6c626c

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 17896 Comm: syz.4.15160 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
==================================================================
EXT4-fs (loop4): orphan cleanup on readonly fs
EXT4-fs error (device loop4): ext4_read_block_bitmap_nowait:483: comm syz.4.15160: Invalid block bitmap block 0 in block_group 0
EXT4-fs (loop4): Remounting filesystem read-only
EXT4-fs (loop4): 1 orphan inode deleted
EXT4-fs (loop4): mounted filesystem 00000000-0000-0000-0000-000000000000 ro without journal. Quota mode: writeback.