audit: type=1326 audit(2000010726.111:55801): auid=4294967295 uid=0 gid=0 ses=4294967295 subj=root:sysadm_r:sysadm_t pid=3020 comm="syz-executor.0" exe="/root/syz-executor.0" sig=31 arch=c000003e syscall=202 compat=0 ip=0x7f4123bd0e69 code=0x0
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BUG: KCSAN: data-race in data_push_tail / vsnprintf

write to 0xffffffff883bfbb1 of 1 bytes by task 2860 on cpu 1:
 vsnprintf+0xdd8/0xe30
 vscnprintf+0x42/0x90 lib/vsprintf.c:2930
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2165
 vprintk_store+0x570/0x810 kernel/printk/printk.c:2279
 vprintk_emit+0x10c/0x5e0 kernel/printk/printk.c:2329
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2363
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2373
 batadv_check_known_mac_addr+0x153/0x180 net/batman-adv/hard-interface.c:528
 batadv_hard_if_event+0x4b0/0x1000 net/batman-adv/hard-interface.c:998
 notifier_call_chain kernel/notifier.c:93 [inline]
 raw_notifier_call_chain+0x6f/0x1d0 kernel/notifier.c:461
 call_netdevice_notifiers_info+0xae/0x100 net/core/dev.c:1950
 call_netdevice_notifiers_extack net/core/dev.c:1988 [inline]
 call_netdevice_notifiers net/core/dev.c:2002 [inline]
 dev_set_mac_address+0x1ff/0x260 net/core/dev.c:8949
 dev_set_mac_address_user+0x31/0x50 net/core/dev.c:8963
 do_setlink+0x510/0x2480 net/core/rtnetlink.c:2839
 __rtnl_newlink net/core/rtnetlink.c:3680 [inline]
 rtnl_newlink+0x11a1/0x1690 net/core/rtnetlink.c:3727
 rtnetlink_rcv_msg+0x82e/0x8e0 net/core/rtnetlink.c:6595
 netlink_rcv_skb+0x12c/0x230 net/netlink/af_netlink.c:2559
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6613
 netlink_unicast_kernel net/netlink/af_netlink.c:1335 [inline]
 netlink_unicast+0x58d/0x660 net/netlink/af_netlink.c:1361
 netlink_sendmsg+0x5d3/0x6e0 net/netlink/af_netlink.c:1905
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x140/0x180 net/socket.c:745
 __sys_sendto+0x1e5/0x260 net/socket.c:2191
 __do_sys_sendto net/socket.c:2203 [inline]
 __se_sys_sendto net/socket.c:2199 [inline]
 __x64_sys_sendto+0x78/0x90 net/socket.c:2199
 x64_sys_call+0x16bb/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:45
 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+0x77/0x7f

read to 0xffffffff883bfbb0 of 8 bytes by task 28 on cpu 0:
 data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline]
 data_push_tail+0x102/0x430 kernel/printk/printk_ringbuffer.c:679
 data_alloc+0xbe/0x2c0 kernel/printk/printk_ringbuffer.c:1054
 prb_reserve+0x85e/0xb60 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x53f/0x810 kernel/printk/printk.c:2269
 vprintk_emit+0x10c/0x5e0 kernel/printk/printk.c:2329
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2363
 vprintk+0x75/0x80 kernel/printk/printk_safe.c:45
 _printk+0x7a/0xa0 kernel/printk/printk.c:2373
 kauditd_printk_skb kernel/audit.c:546 [inline]
 kauditd_hold_skb+0x1a1/0x1b0 kernel/audit.c:581
 kauditd_send_queue+0x288/0x2e0 kernel/audit.c:766
 kauditd_thread+0x42a/0x650 kernel/audit.c:890
 kthread+0x1d1/0x210 kernel/kthread.c:388
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

value changed: 0x000000010000cf19 -> 0x000000010000000a

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 28 Comm: kauditd Tainted: G        W          6.9.0-rc3-syzkaller-00208-g586b5dfb51b9 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
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