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BUG: KCSAN: data-race in data_push_tail / string

write to 0xffffffff86e74de9 of 1 bytes by task 11251 on cpu 0:
 string_nocheck lib/vsprintf.c:647 [inline]
 string+0x17b/0x220 lib/vsprintf.c:725
 vsnprintf+0xb57/0xe80 lib/vsprintf.c:2806
 vscnprintf+0x3e/0x80 lib/vsprintf.c:2912
 printk_sprint kernel/printk/printk.c:2099 [inline]
 vprintk_store+0x61d/0xb40 kernel/printk/printk.c:2209
 vprintk_emit+0xcc/0x430 kernel/printk/printk.c:2256
 vprintk_default+0x22/0x30 kernel/printk/printk.c:2283
 vprintk+0x7f/0x90 kernel/printk/printk_safe.c:50
 _printk+0x76/0x96 kernel/printk/printk.c:2293
 __dev_set_promiscuity+0x179/0x380 net/core/dev.c:8225
 __dev_change_flags+0x1e8/0x3f0 net/core/dev.c:8442
 dev_change_flags+0x55/0xc0 net/core/dev.c:8504
 do_setlink+0x7f9/0x2120 net/core/rtnetlink.c:2731
 rtnl_group_changelink net/core/rtnetlink.c:3265 [inline]
 __rtnl_newlink net/core/rtnetlink.c:3421 [inline]
 rtnl_newlink+0xb08/0x1580 net/core/rtnetlink.c:3531
 rtnetlink_rcv_msg+0x74f/0x7e0 net/core/rtnetlink.c:5993
 netlink_rcv_skb+0x13e/0x240 net/netlink/af_netlink.c:2503
 rtnetlink_rcv+0x18/0x20 net/core/rtnetlink.c:6011
 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline]
 netlink_unicast+0x58a/0x660 net/netlink/af_netlink.c:1345
 netlink_sendmsg+0x661/0x750 net/netlink/af_netlink.c:1921
 sock_sendmsg_nosec net/socket.c:705 [inline]
 sock_sendmsg net/socket.c:725 [inline]
 ____sys_sendmsg+0x38f/0x500 net/socket.c:2413
 ___sys_sendmsg net/socket.c:2467 [inline]
 __sys_sendmsg+0x195/0x230 net/socket.c:2496
 __do_sys_sendmsg net/socket.c:2505 [inline]
 __se_sys_sendmsg net/socket.c:2503 [inline]
 __x64_sys_sendmsg+0x42/0x50 net/socket.c:2503
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffffffff86e74de8 of 8 bytes by task 11381 on cpu 1:
 data_make_reusable kernel/printk/printk_ringbuffer.c:590 [inline]
 data_push_tail+0x10f/0x440 kernel/printk/printk_ringbuffer.c:675
 data_alloc+0xbc/0x2b0 kernel/printk/printk_ringbuffer.c:1046
 prb_reserve+0x897/0xbd0 kernel/printk/printk_ringbuffer.c:1555
 vprintk_store+0x54d/0xb40 kernel/printk/printk.c:2199
 vprintk_emit+0xcc/0x430 kernel/printk/printk.c:2256
 vprintk_default+0x22/0x30 kernel/printk/printk.c:2283
 vprintk+0x7f/0x90 kernel/printk/printk_safe.c:50
 _printk+0x76/0x96 kernel/printk/printk.c:2293
 xt_check_match+0x4aa/0x4c0 net/netfilter/x_tables.c:517
 check_match net/ipv4/netfilter/ip_tables.c:473 [inline]
 find_check_match net/ipv4/netfilter/ip_tables.c:489 [inline]
 find_check_entry net/ipv4/netfilter/ip_tables.c:539 [inline]
 translate_table+0xad8/0xfb0 net/ipv4/netfilter/ip_tables.c:718
 do_replace net/ipv4/netfilter/ip_tables.c:1136 [inline]
 do_ipt_set_ctl+0x13d7/0x16e0 net/ipv4/netfilter/ip_tables.c:1630
 nf_setsockopt+0x1a6/0x1c0 net/netfilter/nf_sockopt.c:101
 ip_setsockopt+0x1741/0x1ea0 net/ipv4/ip_sockglue.c:1444
 raw_setsockopt+0x100/0x150 net/ipv4/raw.c:861
 sock_common_setsockopt+0x5d/0x70 net/core/sock.c:3505
 __sys_setsockopt+0x212/0x2b0 net/socket.c:2180
 __do_sys_setsockopt net/socket.c:2191 [inline]
 __se_sys_setsockopt net/socket.c:2188 [inline]
 __x64_sys_setsockopt+0x62/0x70 net/socket.c:2188
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000100005f93 -> 0x6d6f727020746665

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 11381 Comm: syz-executor.0 Not tainted 5.18.0-rc6-syzkaller-00009-gfeb9c5e19e91 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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