audit: type=1326 audit(1743099940.310:5882): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=25780 comm="syz.0.6279" exe="/root/syz-executor" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7f3983e9d169 code=0x7ffc0000
==================================================================
BUG: KCSAN: data-race in data_push_tail / number

write to 0xffffffff88e0aed7 of 1 bytes by task 25790 on cpu 1:
 number+0x7f2/0xac0 lib/vsprintf.c:558
 vsnprintf+0x6b0/0x8a0 lib/vsprintf.c:2814
 vscnprintf+0x42/0x90 lib/vsprintf.c:2915
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2216
 vprintk_store+0x583/0x860 kernel/printk/printk.c:2336
 vprintk_emit+0x174/0x6a0 kernel/printk/printk.c:2408
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2447
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7f/0xb0 kernel/printk/printk.c:2457
 set_capacity_and_notify+0x155/0x200 block/genhd.c:93
 loop_set_size+0x2e/0x70 drivers/block/loop.c:210
 loop_configure+0x89c/0xa30 drivers/block/loop.c:1120
 lo_ioctl+0x5fa/0x1570 drivers/block/loop.c:-1
 blkdev_ioctl+0x35b/0x450 block/ioctl.c:698
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:906 [inline]
 __se_sys_ioctl+0xc9/0x140 fs/ioctl.c:892
 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:892
 x64_sys_call+0x168d/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:17
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff88e0aed0 of 8 bytes by task 29 on cpu 0:
 data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline]
 data_push_tail+0x107/0x440 kernel/printk/printk_ringbuffer.c:679
 data_alloc+0xbd/0x2c0 kernel/printk/printk_ringbuffer.c:1054
 prb_reserve+0x86a/0xb80 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x552/0x860 kernel/printk/printk.c:2326
 vprintk_emit+0x174/0x6a0 kernel/printk/printk.c:2408
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2447
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7f/0xb0 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+0x432/0x640 kernel/audit.c:890
 kthread+0x4ae/0x520 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x000000010000085e -> 0x742030206d6f7266

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 29 Comm: kauditd Not tainted 6.14.0-syzkaller-05877-g1a9239bb4253 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================
audit: type=1326 audit(1743099940.310:5883): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=25780 comm="syz.0.6279" exe="/root/syz-executor" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7f3983e9d169 code=0x7ffc0000
audit: type=1326 audit(1743099940.320:5884): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=25780 comm="syz.0.6279" exe="/root/syz-executor" sig=0 arch=c000003e syscall=157 compat=0 ip=0x7f3983e9d169 code=0x7ffc0000
audit: type=1326 audit(1743099940.320:5885): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=25780 comm="syz.0.6279" exe="/root/syz-executor" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7f3983e9d169 code=0x7ffc0000