EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.
==================================================================
BUG: KCSAN: data-race in data_push_tail / string

write to 0xffffffff88b96e0b of 1 bytes by task 7942 on cpu 0:
 string_nocheck lib/vsprintf.c:650 [inline]
 string+0x16c/0x210 lib/vsprintf.c:728
 vsnprintf+0xa09/0xe30 lib/vsprintf.c:2803
 vscnprintf+0x42/0x90 lib/vsprintf.c:2909
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2197
 vprintk_store+0x570/0x810 kernel/printk/printk.c:2311
 vprintk_emit+0x15e/0x680 kernel/printk/printk.c:2383
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2422
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:68
 _printk+0x7a/0xa0 kernel/printk/printk.c:2432
 __ext4_msg+0x18e/0x1a0 fs/ext4/super.c:991
 ext4_fill_super+0x980/0x3a10 fs/ext4/super.c:5701
 get_tree_bdev+0x256/0x2e0 fs/super.c:1635
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5718
 vfs_get_tree+0x56/0x1e0 fs/super.c:1800
 do_new_mount+0x227/0x690 fs/namespace.c:3507
 path_mount+0x49b/0xb30 fs/namespace.c:3834
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4055 [inline]
 __se_sys_mount+0x27c/0x2d0 fs/namespace.c:4032
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4032
 x64_sys_call+0x203e/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:166
 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 0xffffffff88b96e08 of 8 bytes by task 7940 on cpu 1:
 data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline]
 data_push_tail+0x102/0x430 kernel/printk/printk_ringbuffer.c:679
 data_alloc+0xbe/0x2c0 kernel/printk/printk_ringbuffer.c:1054
 prb_reserve+0x85e/0xb60 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x53f/0x810 kernel/printk/printk.c:2301
 vprintk_emit+0x15e/0x680 kernel/printk/printk.c:2383
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2422
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:68
 _printk+0x7a/0xa0 kernel/printk/printk.c:2432
 __ext4_msg+0x18e/0x1a0 fs/ext4/super.c:991
 ext4_fill_super+0x980/0x3a10 fs/ext4/super.c:5701
 get_tree_bdev+0x256/0x2e0 fs/super.c:1635
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5718
 vfs_get_tree+0x56/0x1e0 fs/super.c:1800
 do_new_mount+0x227/0x690 fs/namespace.c:3507
 path_mount+0x49b/0xb30 fs/namespace.c:3834
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4055 [inline]
 __se_sys_mount+0x27c/0x2d0 fs/namespace.c:4032
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4032
 x64_sys_call+0x203e/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:166
 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: 0x00000000ffffe387 -> 0x33706f6f6c282073

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 7940 Comm: syz.0.746 Not tainted 6.12.0-rc2-syzkaller-00307-g36c254515dc6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================
ext4 filesystem being mounted at /164/bus supports timestamps until 2038-01-19 (0x7fffffff)
EXT4-fs (loop0): unmounting filesystem 00000000-0000-0000-0000-000000000000.