syzbot

netlink: 'syz.3.5949': attribute type 1 has an invalid length.
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BUG: KCSAN: data-race in data_push_tail / string

write to 0xffffffff88e485c4 of 1 bytes by task 20206 on cpu 1:
 string_nocheck lib/vsprintf.c:643 [inline]
 string+0x17d/0x210 lib/vsprintf.c:721
 vsnprintf+0x539/0x8a0 lib/vsprintf.c:2850
 vscnprintf+0x42/0x90 lib/vsprintf.c:2915
 printk_sprint+0x30/0x2d0 kernel/printk/printk.c:2216
 vprintk_store+0x583/0x860 kernel/printk/printk.c:2336
 vprintk_emit+0x1a0/0x6c0 kernel/printk/printk.c:2426
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7f/0xb0 kernel/printk/printk.c:2475
 __nla_validate_parse+0x1928/0x1f60 lib/nlattr.c:647
 __nla_parse+0x40/0x60 lib/nlattr.c:732
 __nlmsg_parse include/net/netlink.h:765 [inline]
 nlmsg_parse_deprecated include/net/netlink.h:806 [inline]
 rtnl_newlink+0xf4/0x12d0 net/core/rtnetlink.c:3967
 rtnetlink_rcv_msg+0x65a/0x740 net/core/rtnetlink.c:6952
 netlink_rcv_skb+0x12f/0x230 net/netlink/af_netlink.c:2534
 rtnetlink_rcv+0x1c/0x30 net/core/rtnetlink.c:6979
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x605/0x6c0 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x609/0x720 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x140/0x180 net/socket.c:727
 sock_sendmsg+0xce/0x130 net/socket.c:750
 splice_to_socket+0x666/0xa00 fs/splice.c:883
 do_splice_from fs/splice.c:935 [inline]
 do_splice+0x9e4/0x1160 fs/splice.c:1348
 __do_splice fs/splice.c:1430 [inline]
 __do_sys_splice fs/splice.c:1633 [inline]
 __se_sys_splice+0x254/0x3b0 fs/splice.c:1615
 __x64_sys_splice+0x78/0x90 fs/splice.c:1615
 x64_sys_call+0xf5b/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:276
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff88e485c0 of 8 bytes by task 20205 on cpu 0:
 data_make_reusable kernel/printk/printk_ringbuffer.c:594 [inline]
 data_push_tail+0x107/0x440 kernel/printk/printk_ringbuffer.c:679
 data_alloc+0xbd/0x2c0 kernel/printk/printk_ringbuffer.c:1054
 prb_reserve+0x86a/0xb80 kernel/printk/printk_ringbuffer.c:1669
 vprintk_store+0x552/0x860 kernel/printk/printk.c:2326
 vprintk_emit+0x1a0/0x6c0 kernel/printk/printk.c:2426
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2465
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x7f/0xb0 kernel/printk/printk.c:2475
 validate_nla lib/nlattr.c:414 [inline]
 __nla_validate_parse+0x131a/0x1f60 lib/nlattr.c:635
 __nla_parse+0x40/0x60 lib/nlattr.c:732
 __nlmsg_parse include/net/netlink.h:765 [inline]
 genl_family_rcv_msg_attrs_parse+0x14b/0x1a0 net/netlink/genetlink.c:945
 genl_family_rcv_msg_doit net/netlink/genetlink.c:1093 [inline]
 genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
 genl_rcv_msg+0x486/0x6f0 net/netlink/genetlink.c:1210
 netlink_rcv_skb+0x12f/0x230 net/netlink/af_netlink.c:2534
 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x605/0x6c0 net/netlink/af_netlink.c:1339
 netlink_sendmsg+0x609/0x720 net/netlink/af_netlink.c:1883
 sock_sendmsg_nosec net/socket.c:712 [inline]
 __sock_sendmsg+0x140/0x180 net/socket.c:727
 ____sys_sendmsg+0x350/0x4e0 net/socket.c:2566
 ___sys_sendmsg net/socket.c:2620 [inline]
 __sys_sendmsg+0x1a0/0x240 net/socket.c:2652
 __do_sys_sendmsg net/socket.c:2657 [inline]
 __se_sys_sendmsg net/socket.c:2655 [inline]
 __x64_sys_sendmsg+0x46/0x50 net/socket.c:2655
 x64_sys_call+0x26f3/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000fffff107 -> 0x2e342e7a79736020

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 20205 Comm: syz.3.5949 Not tainted 6.14.0-syzkaller-10514-g7f2ff7b62617 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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