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

write to 0xffffffff88be3e4d of 1 bytes by task 18542 on cpu 1:
 number+0x88c/0xac0 lib/vsprintf.c:551
 vsnprintf+0x6ae/0x890 lib/vsprintf.c:2807
 vscnprintf+0x42/0x90 lib/vsprintf.c:2908
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2216
 vprintk_store+0x589/0x870 kernel/printk/printk.c:2336
 vprintk_emit+0x168/0x690 kernel/printk/printk.c:2408
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2447
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7a/0xa0 kernel/printk/printk.c:2457
 __show_regs+0x86/0x450 arch/x86/kernel/process_64.c:83
 show_trace_log_lvl+0x348/0x400 arch/x86/kernel/dumpstack.c:301
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0xf2/0x150 lib/dump_stack.c:120
 dump_stack+0x15/0x1a lib/dump_stack.c:129
 fail_dump lib/fault-inject.c:73 [inline]
 should_fail_ex+0x24a/0x260 lib/fault-inject.c:174
 should_fail+0xb/0x10 lib/fault-inject.c:184
 should_fail_usercopy+0x1a/0x20 lib/fault-inject-usercopy.c:37
 _inline_copy_from_user include/linux/uaccess.h:163 [inline]
 _copy_from_user+0x1c/0xa0 lib/usercopy.c:18
 copy_from_user include/linux/uaccess.h:212 [inline]
 copy_msghdr_from_user+0x54/0x2a0 net/socket.c:2503
 sendmsg_copy_msghdr net/socket.c:2604 [inline]
 ___sys_sendmsg net/socket.c:2623 [inline]
 __sys_sendmmsg+0x1e8/0x4b0 net/socket.c:2716
 __do_sys_sendmmsg net/socket.c:2743 [inline]
 __se_sys_sendmmsg net/socket.c:2740 [inline]
 __x64_sys_sendmmsg+0x57/0x70 net/socket.c:2740
 x64_sys_call+0x29aa/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:308
 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 0xffffffff88be3e48 of 8 bytes by task 29 on cpu 0:
 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+0x558/0x870 kernel/printk/printk.c:2326
 vprintk_emit+0x168/0x690 kernel/printk/printk.c:2408
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2447
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7a/0xa0 kernel/printk/printk.c:2457
 kauditd_printk_skb kernel/audit.c:546 [inline]
 kauditd_hold_skb+0x1a3/0x1b0 kernel/audit.c:581
 kauditd_send_queue+0x288/0x2e0 kernel/audit.c:766
 kauditd_thread+0x42a/0x650 kernel/audit.c:890
 kthread+0x4ae/0x520 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x00000001000009b3 -> 0x000000203a584152

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 29 Comm: kauditd Tainted: G        W          6.14.0-rc7-syzkaller-00202-g183601b78a9b #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================
audit: type=1326 audit(1742744766.507:16722): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=18541 comm="syz.8.5322" exe="/root/syz-executor" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7f93a1d6d169 code=0x7ffc0000
audit: type=1326 audit(1742744766.507:16723): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=18541 comm="syz.8.5322" exe="/root/syz-executor" sig=0 arch=c000003e syscall=447 compat=0 ip=0x7f93a1d6d169 code=0x7ffc0000
audit: type=1326 audit(1742744766.507:16724): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=18541 comm="syz.8.5322" exe="/root/syz-executor" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7f93a1d6d169 code=0x7ffc0000
audit: type=1326 audit(1742744766.507:16725): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=18541 comm="syz.8.5322" exe="/root/syz-executor" sig=0 arch=c000003e syscall=321 compat=0 ip=0x7f93a1d6d169 code=0x7ffc0000
audit: type=1326 audit(1742744766.507:16726): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=18541 comm="syz.8.5322" exe="/root/syz-executor" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7f93a1d6d169 code=0x7ffc0000
audit: type=1326 audit(1742744766.507:16727): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=18541 comm="syz.8.5322" exe="/root/syz-executor" sig=0 arch=c000003e syscall=41 compat=0 ip=0x7f93a1d6d169 code=0x7ffc0000
audit: type=1326 audit(1742744766.507:16728): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=18541 comm="syz.8.5322" exe="/root/syz-executor" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7f93a1d6d169 code=0x7ffc0000
audit: type=1326 audit(1742744766.507:16729): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=18541 comm="syz.8.5322" exe="/root/syz-executor" sig=0 arch=c000003e syscall=49 compat=0 ip=0x7f93a1d6d169 code=0x7ffc0000