audit: type=1400 audit(1748216690.993:15231): avc:  denied  { mounton } for  pid=15224 comm="syz.2.3909" path="/227/file0" dev="tmpfs" ino=1211 scontext=root:sysadm_r:sysadm_t tcontext=root:object_r:user_tmpfs_t tclass=dir permissive=1
==================================================================
BUG: KCSAN: data-race in data_push_tail / vsnprintf

write to 0xffffffff88e0ec28 of 46 bytes by task 15225 on cpu 1:
 vsnprintf+0x2ce/0x890 lib/vsprintf.c:2804
 vscnprintf+0x41/0x90 lib/vsprintf.c:2917
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2216
 vprintk_store+0x599/0x860 kernel/printk/printk.c:2336
 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2475
 p9_fd_create+0x20c/0x280 net/9p/trans_fd.c:1093
 p9_client_create+0x60b/0xbc0 net/9p/client.c:1017
 v9fs_session_init+0xf7/0xde0 fs/9p/v9fs.c:410
 v9fs_mount+0x67/0x590 fs/9p/vfs_super.c:122
 legacy_get_tree+0x78/0xd0 fs/fs_context.c:662
 vfs_get_tree+0x57/0x1d0 fs/super.c:1759
 do_new_mount+0x207/0x680 fs/namespace.c:3881
 path_mount+0x4a4/0xb20 fs/namespace.c:4208
 do_mount fs/namespace.c:4221 [inline]
 __do_sys_mount fs/namespace.c:4432 [inline]
 __se_sys_mount+0x28f/0x2e0 fs/namespace.c:4409
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4409
 x64_sys_call+0xd36/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff88e0ec48 of 8 bytes by task 29 on cpu 0:
 data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline]
 data_push_tail+0xfd/0x420 kernel/printk/printk_ringbuffer.c:679
 data_alloc+0xbf/0x2b0 kernel/printk/printk_ringbuffer.c:1054
 prb_reserve+0x808/0xaf0 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2326
 vprintk_emit+0x178/0x650 kernel/printk/printk.c:2426
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2475
 kauditd_printk_skb kernel/audit.c:546 [inline]
 kauditd_hold_skb+0x1b1/0x1c0 kernel/audit.c:581
 kauditd_send_queue+0x273/0x2c0 kernel/audit.c:766
 kauditd_thread+0x421/0x630 kernel/audit.c:890
 kthread+0x486/0x510 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: 0x00000000fffff7e7 -> 0x6f746f727020726f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 29 Comm: kauditd Not tainted 6.15.0-rc7-syzkaller-00175-g0f8c0258bf04 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
==================================================================
audit: type=1326 audit(1748216691.153:15232): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=15227 comm="syz.5.3910" exe="/root/syz-executor" sig=31 arch=c000003e syscall=202 compat=0 ip=0x7fa8dc69e969 code=0x0
audit: type=1400 audit(1748216691.323:15233): avc:  denied  { mount } for  pid=15224 comm="syz.2.3909" name="/" dev="loop2" ino=2 scontext=root:sysadm_r:sysadm_t tcontext=system_u:object_r:fs_t tclass=filesystem permissive=1