==================================================================
BUG: KCSAN: data-race in data_alloc / prb_reserve

write to 0xffffffff8667cc08 of 8 bytes by task 25785 on cpu 1:
 data_alloc+0x291/0x2c0 kernel/printk/printk_ringbuffer.c:1096
 prb_reserve+0x85e/0xb60 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x558/0x870 kernel/printk/printk.c:2326
 vprintk_emit+0x15e/0x680 kernel/printk/printk.c:2408
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2447
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:86
 _printk+0x7a/0xa0 kernel/printk/printk.c:2457
 __ext4_warning_inode+0x17c/0x190 fs/ext4/super.c:1040
 __warn_no_space_for_csum fs/ext4/namei.c:393 [inline]
 ext4_dirblock_csum_verify+0x162/0x330 fs/ext4/namei.c:406
 ext4_readdir+0x809/0x1ba0 fs/ext4/dir.c:218
 iterate_dir+0x11d/0x310 fs/readdir.c:108
 __do_sys_getdents64 fs/readdir.c:403 [inline]
 __se_sys_getdents64+0x87/0x1a0 fs/readdir.c:389
 __x64_sys_getdents64+0x43/0x50 fs/readdir.c:389
 x64_sys_call+0x2d24/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:218
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff8667cc08 of 8 bytes by task 24095 on cpu 0:
 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+0x235/0xb60 kernel/printk/printk_ringbuffer.c:1619
 vprintk_store+0x558/0x870 kernel/printk/printk.c:2326
 vprintk_emit+0x15e/0x680 kernel/printk/printk.c:2408
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2447
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:86
 _printk+0x7a/0xa0 kernel/printk/printk.c:2457
 __ext4_error_file+0x2e1/0x410 fs/ext4/super.c:900
 ext4_readdir+0xa60/0x1ba0 fs/ext4/dir.c:219
 iterate_dir+0x11d/0x310 fs/readdir.c:108
 __do_sys_getdents64 fs/readdir.c:403 [inline]
 __se_sys_getdents64+0x87/0x1a0 fs/readdir.c:389
 __x64_sys_getdents64+0x43/0x50 fs/readdir.c:389
 x64_sys_call+0x2d24/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:218
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000000b2380 -> 0x00000000001546e0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 24095 Comm: syz-executor Not tainted 6.13.0-rc4-syzkaller-00110-g4099a71718b0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================
EXT4-fs error (device loop6): ext4_readdir:221: inode #11: comm syz-executor: path /367/file1/lost+found: directory fails checksum at offset 5120
EXT4-fs warning (device loop6): ext4_dirblock_csum_verify:406: inode #11: comm syz-executor: No space for directory leaf checksum. Please run e2fsck -D.
EXT4-fs warning (device loop6): ext4_dirblock_csum_verify:406: inode #11: comm syz-executor: No space for directory leaf checksum. Please run e2fsck -D.
EXT4-fs warning (device loop6): ext4_dirblock_csum_verify:406: inode #11: comm syz-executor: No space for directory leaf checksum. Please run e2fsck -D.
EXT4-fs warning (device loop6): ext4_dirblock_csum_verify:406: inode #11: comm syz-executor: No space for directory leaf checksum. Please run e2fsck -D.
EXT4-fs warning (device loop6): ext4_dirblock_csum_verify:406: inode #11: comm syz-executor: No space for directory leaf checksum. Please run e2fsck -D.
EXT4-fs warning (device loop6): ext4_dirblock_csum_verify:406: inode #11: comm syz-executor: No space for directory leaf checksum. Please run e2fsck -D.
EXT4-fs warning (device loop6): ext4_dirblock_csum_verify:406: inode #11: comm syz-executor: No space for directory leaf checksum. Please run e2fsck -D.
EXT4-fs warning (device loop6): ext4_dirblock_csum_verify:406: inode #11: comm syz-executor: No space for directory leaf checksum. Please run e2fsck -D.
EXT4-fs (loop6): unmounting filesystem 76b65be2-f6da-4727-8c75-0525a5b65a09.