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

write to 0xffffffff86eefdd8 of 1 bytes by task 7347 on cpu 1:
 number+0x8b5/0xa90 lib/vsprintf.c:562
 vsnprintf+0xa44/0xe20 lib/vsprintf.c:2862
 vscnprintf+0x42/0x80 lib/vsprintf.c:2902
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2137
 vprintk_store+0x56f/0x800 kernel/printk/printk.c:2251
 vprintk_emit+0xd0/0x430 kernel/printk/printk.c:2297
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2327
 vprintk+0x83/0x90 kernel/printk/printk_safe.c:50
 _printk+0x7a/0xa0 kernel/printk/printk.c:2337
 mnt_warn_timestamp_expiry+0x216/0x250 fs/namespace.c:2624
 do_new_mount_fc fs/namespace.c:2983 [inline]
 do_new_mount+0x2ef/0x650 fs/namespace.c:3044
 path_mount+0x498/0xb40 fs/namespace.c:3372
 do_mount fs/namespace.c:3385 [inline]
 __do_sys_mount fs/namespace.c:3594 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3571
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3571
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffffffff86eefdd8 of 8 bytes by task 7348 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:2241
 vprintk_emit+0xd0/0x430 kernel/printk/printk.c:2297
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2327
 vprintk+0x83/0x90 kernel/printk/printk_safe.c:50
 _printk+0x7a/0xa0 kernel/printk/printk.c:2337
 mnt_warn_timestamp_expiry+0x216/0x250 fs/namespace.c:2624
 do_new_mount_fc fs/namespace.c:2983 [inline]
 do_new_mount+0x2ef/0x650 fs/namespace.c:3044
 path_mount+0x498/0xb40 fs/namespace.c:3372
 do_mount fs/namespace.c:3385 [inline]
 __do_sys_mount fs/namespace.c:3594 [inline]
 __se_sys_mount+0x27f/0x2d0 fs/namespace.c:3571
 __x64_sys_mount+0x67/0x80 fs/namespace.c:3571
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x000000010000c7dc -> 0x000000000a296629

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 7348 Comm: syz-executor.2 Not tainted 6.3.0-rc6-syzkaller-00035-g0bcc40255504 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
==================================================================