audit: type=1326 audit(2000000031.080:19053): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=21338 comm="syz.5.5823" exe="/root/syz-executor" sig=0 arch=c000003e syscall=285 compat=0 ip=0x7f7438bed169 code=0x7ffc0000
audit: type=1326 audit(2000000031.080:19054): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=21338 comm="syz.5.5823" exe="/root/syz-executor" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7f7438bed169 code=0x7ffc0000
==================================================================
BUG: KCSAN: data-race in desc_read_finalized_seq / prb_reserve

write to 0xffffffff868a80b0 of 8 bytes by task 21335 on cpu 0:
 prb_reserve+0x750/0xb80 kernel/printk/printk_ringbuffer.c:-1
 vprintk_store+0x552/0x860 kernel/printk/printk.c:2326
 vprintk_emit+0x1a0/0x6c0 kernel/printk/printk.c:2426
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7f/0xb0 kernel/printk/printk.c:2475
 __ext4_warning+0x13c/0x150 fs/ext4/super.c:1010
 ext4_enable_quotas+0x3a4/0x420 fs/ext4/super.c:7166
 __ext4_remount fs/ext4/super.c:6705 [inline]
 ext4_reconfigure+0x118d/0x1720 fs/ext4/super.c:6791
 reconfigure_super+0x319/0x5b0 fs/super.c:1083
 do_remount fs/namespace.c:3363 [inline]
 path_mount+0x96a/0xb30 fs/namespace.c:4198
 do_mount fs/namespace.c:4219 [inline]
 __do_sys_mount fs/namespace.c:4430 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4407
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4407
 x64_sys_call+0xd11/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:166
 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 0xffffffff868a80b0 of 8 bytes by task 29 on cpu 1:
 desc_read kernel/printk/printk_ringbuffer.c:486 [inline]
 desc_read_finalized_seq+0x163/0x280 kernel/printk/printk_ringbuffer.c:1874
 prb_read kernel/printk/printk_ringbuffer.c:1922 [inline]
 _prb_read_valid+0x142/0x710 kernel/printk/printk_ringbuffer.c:2113
 prb_read_valid+0x42/0x70 kernel/printk/printk_ringbuffer.c:2185
 printk_get_next_message+0xdc/0x530 kernel/printk/printk.c:3005
 console_emit_next_record kernel/printk/printk.c:3092 [inline]
 console_flush_all+0x2a9/0x7a0 kernel/printk/printk.c:3226
 __console_flush_and_unlock kernel/printk/printk.c:3285 [inline]
 console_unlock+0xf4/0x350 kernel/printk/printk.c:3325
 vprintk_emit+0x470/0x6c0 kernel/printk/printk.c:2450
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7f/0xb0 kernel/printk/printk.c:2475
 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+0x4b7/0x540 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: 0x000000000000229e -> 0x000000000000429e

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 29 Comm: kauditd Not tainted 6.15.0-rc2-syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================
audit: type=1326 audit(2000000031.080:19055): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=21338 comm="syz.5.5823" exe="/root/syz-executor" sig=0 arch=c000003e syscall=202 compat=0 ip=0x7f7438bed169 code=0x7ffc0000