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BUG: KCSAN: data-race in data_alloc / prb_reserve

write to 0xffffffff85c64470 of 8 bytes by task 21400 on cpu 1:
 data_alloc+0x291/0x2c0 kernel/printk/printk_ringbuffer.c:1088
 prb_reserve+0x897/0xbc0 kernel/printk/printk_ringbuffer.c:1555
 vprintk_store+0x53e/0x800 kernel/printk/printk.c:2228
 vprintk_emit+0xd0/0x5d0 kernel/printk/printk.c:2284
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2318
 vprintk+0x71/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2328
 selinux_netlink_send+0x3fe/0x470 security/selinux/hooks.c:5964
 security_netlink_send+0x3e/0x70 security/security.c:4113
 netlink_sendmsg+0x563/0x770 net/netlink/af_netlink.c:1898
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x37c/0x4d0 net/socket.c:2584
 ___sys_sendmsg net/socket.c:2638 [inline]
 __sys_sendmsg+0x1e9/0x270 net/socket.c:2667
 __do_sys_sendmsg net/socket.c:2676 [inline]
 __se_sys_sendmsg net/socket.c:2674 [inline]
 __x64_sys_sendmsg+0x46/0x50 net/socket.c:2674
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffffffff85c64470 of 8 bytes by task 21401 on cpu 0:
 desc_read kernel/printk/printk_ringbuffer.c:478 [inline]
 desc_push_tail kernel/printk/printk_ringbuffer.c:774 [inline]
 desc_reserve kernel/printk/printk_ringbuffer.c:920 [inline]
 prb_reserve+0x229/0xbc0 kernel/printk/printk_ringbuffer.c:1505
 vprintk_store+0x53e/0x800 kernel/printk/printk.c:2228
 vprintk_emit+0xd0/0x5d0 kernel/printk/printk.c:2284
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2318
 vprintk+0x71/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2328
 selinux_netlink_send+0x3fe/0x470 security/selinux/hooks.c:5964
 security_netlink_send+0x3e/0x70 security/security.c:4113
 netlink_sendmsg+0x563/0x770 net/netlink/af_netlink.c:1898
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 ____sys_sendmsg+0x37c/0x4d0 net/socket.c:2584
 ___sys_sendmsg net/socket.c:2638 [inline]
 __sys_sendmsg+0x1e9/0x270 net/socket.c:2667
 __do_sys_sendmsg net/socket.c:2676 [inline]
 __se_sys_sendmsg net/socket.c:2674 [inline]
 __x64_sys_sendmsg+0x46/0x50 net/socket.c:2674
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0xfffffffffffcc928 -> 0x0000000000056a58

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 21401 Comm: syz-executor.4 Not tainted 6.8.0-rc6-syzkaller-00021-gcf1182944c7c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
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SELinux: unrecognized netlink message: protocol=0 nlmsg_type=5130 sclass=netlink_route_socket pid=21401 comm=syz-executor.4