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

write to 0xffffffff86ed1ab5 of 1 bytes by task 8663 on cpu 1:
 string_nocheck lib/vsprintf.c:650 [inline]
 string+0x16c/0x200 lib/vsprintf.c:728
 vsnprintf+0xa09/0xe20 lib/vsprintf.c:2819
 va_format lib/vsprintf.c:1683 [inline]
 pointer+0x8a1/0xd10 lib/vsprintf.c:2450
 vsnprintf+0x861/0xe20 lib/vsprintf.c:2823
 vscnprintf+0x42/0x80 lib/vsprintf.c:2925
 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
 _fat_msg+0xa2/0xd0 fs/fat/misc.c:62
 parse_options fs/fat/inode.c:1361 [inline]
 fat_fill_super+0x23f2/0x28e0 fs/fat/inode.c:1646
 vfat_fill_super+0x30/0x40 fs/fat/namei_vfat.c:1200
 mount_bdev+0x185/0x1f0 fs/super.c:1650
 vfat_mount+0x31/0x40 fs/fat/namei_vfat.c:1207
 legacy_get_tree+0x74/0xd0 fs/fs_context.c:662
 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 0xffffffff86ed1ab0 of 8 bytes by task 8662 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+0x130/0x1a0 fs/ext4/super.c:1008
 ext4_parse_param+0x8cd/0xf80 fs/ext4/super.c:2206
 vfs_parse_fs_param+0x136/0x290 fs/fs_context.c:146
 vfs_parse_fs_string fs/fs_context.c:188 [inline]
 vfs_parse_monolithic_sep fs/fs_context.c:230 [inline]
 generic_parse_monolithic+0x165/0x1d0 fs/fs_context.c:258
 parse_monolithic_mount_data+0x42/0x50 fs/fs_context.c:719
 do_new_mount+0x1d6/0x660 fs/namespace.c:3333
 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: 0x0000000100000af0 -> 0x00000022206e6f69

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8662 Comm: syz-executor.5 Not tainted 6.7.0-rc6-syzkaller-00044-g1a44b0073b92 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
==================================================================
EXT4-fs (loop5): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.