==================================================================
BUG: KCSAN: data-race in data_push_tail / string

write to 0xffffffff86edc180 of 1 bytes by task 4306 on cpu 1:
 string_nocheck lib/vsprintf.c:650 [inline]
 string+0x16c/0x200 lib/vsprintf.c:728
 vsnprintf+0xa09/0xe20 lib/vsprintf.c:2824
 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
 __ext4_msg+0x18a/0x1a0 fs/ext4/super.c:1006
 ext4_orphan_cleanup+0x8ec/0x9b0 fs/ext4/orphan.c:497
 __ext4_fill_super fs/ext4/super.c:5591 [inline]
 ext4_fill_super+0x3660/0x39a0 fs/ext4/super.c:5712
 get_tree_bdev+0x272/0x300 fs/super.c:1598
 ext4_get_tree+0x1c/0x20 fs/ext4/super.c:5744
 vfs_get_tree+0x51/0x1b0 fs/super.c:1771
 do_new_mount+0x203/0x660 fs/namespace.c:3337
 path_mount+0x496/0xb30 fs/namespace.c:3664
 do_mount fs/namespace.c:3677 [inline]
 __do_sys_mount fs/namespace.c:3886 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3863
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3863
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffffffff86edc180 of 8 bytes by task 4295 on cpu 0:
 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_msg+0x18a/0x1a0 fs/ext4/super.c:1006
 ext4_orphan_cleanup+0x8ec/0x9b0 fs/ext4/orphan.c:497
 __ext4_fill_super fs/ext4/super.c:5591 [inline]
 ext4_fill_super+0x3660/0x39a0 fs/ext4/super.c:5712
 get_tree_bdev+0x272/0x300 fs/super.c:1598
 ext4_get_tree+0x1c/0x20 fs/ext4/super.c:5744
 vfs_get_tree+0x51/0x1b0 fs/super.c:1771
 do_new_mount+0x203/0x660 fs/namespace.c:3337
 path_mount+0x496/0xb30 fs/namespace.c:3664
 do_mount fs/namespace.c:3677 [inline]
 __do_sys_mount fs/namespace.c:3886 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3863
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3863
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x000000010000741d -> 0x2073662d34545845

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 4295 Comm: syz-executor.0 Not tainted 6.7.0-rc7-syzkaller-00003-gfbafc3e621c3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
==================================================================
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 ro without journal. Quota mode: writeback.