audit: type=1400 audit(2000000406.742:5154): avc:  denied  { create } for  pid=25356 comm="syz.8.6224" scontext=root:sysadm_r:sysadm_t tcontext=root:sysadm_r:sysadm_t tclass=netlink_fib_lookup_socket permissive=1
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BUG: KCSAN: data-race in data_alloc / data_push_tail

write to 0xffffffff895aa298 of 8 bytes by task 25360 on cpu 1:
 data_alloc+0x259/0x390 kernel/printk/printk_ringbuffer.c:1116
 prb_reserve+0x8d6/0xad0 kernel/printk/printk_ringbuffer.c:1727
 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2354
 vprintk_emit+0x1a4/0x600 kernel/printk/printk.c:2455
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2504
 __show_regs+0xf0/0x430 arch/x86/kernel/process_64.c:93
 show_regs_if_on_stack arch/x86/kernel/dumpstack.c:165 [inline]
 __show_trace_log_lvl+0x38f/0x560 arch/x86/kernel/dumpstack.c:298
 __dump_stack+0x1d/0x30 lib/dump_stack.c:94
 dump_stack_lvl+0x95/0xd0 lib/dump_stack.c:120
 dump_stack+0x15/0x1b lib/dump_stack.c:129
 fail_dump lib/fault-inject.c:73 [inline]
 should_fail_ex+0x263/0x280 lib/fault-inject.c:174
 should_fail+0xb/0x20 lib/fault-inject.c:184
 should_fail_usercopy+0x1a/0x20 lib/fault-inject-usercopy.c:35
 _inline_copy_from_user include/linux/uaccess.h:170 [inline]
 _copy_from_user+0x1c/0xb0 lib/usercopy.c:18
 copy_from_user include/linux/uaccess.h:223 [inline]
 move_addr_to_kernel net/socket.c:255 [inline]
 __sys_sendto+0x1ca/0x490 net/socket.c:2255
 __do_sys_sendto net/socket.c:2272 [inline]
 __se_sys_sendto net/socket.c:2268 [inline]
 __x64_sys_sendto+0x76/0x90 net/socket.c:2268
 x64_sys_call+0x2d35/0x3020 arch/x86/include/generated/asm/syscalls_64.h:45
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff895aa298 of 8 bytes by task 28 on cpu 0:
 data_make_reusable kernel/printk/printk_ringbuffer.c:608 [inline]
 data_push_tail+0x100/0x470 kernel/printk/printk_ringbuffer.c:693
 data_alloc+0x11b/0x390 kernel/printk/printk_ringbuffer.c:1089
 prb_reserve+0x8d6/0xad0 kernel/printk/printk_ringbuffer.c:1727
 vprintk_store+0x54a/0x910 kernel/printk/printk.c:2354
 vprintk_emit+0x1a4/0x600 kernel/printk/printk.c:2455
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2494
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2504
 kauditd_printk_skb kernel/audit.c:587 [inline]
 kauditd_hold_skb+0x1b1/0x1c0 kernel/audit.c:622
 kauditd_send_queue+0x273/0x2c0 kernel/audit.c:807
 kauditd_thread+0x444/0x670 kernel/audit.c:931
 kthread+0x22a/0x280 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x000000000000155e -> 0x00000000000022be

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 28 Comm: kauditd Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
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