netlink: 28 bytes leftover after parsing attributes in process `syz.6.9944'.
netlink: 28 bytes leftover after parsing attributes in process `syz.6.9944'.
netlink: 28 bytes leftover after parsing attributes in process `syz.6.9944'.
netlink: 28 bytes leftover after parsing attributes in process `syz.6.9944'.
==================================================================
BUG: KCSAN: data-race in _prb_read_valid / prb_reserve

write to 0xffffffff868e1608 of 88 bytes by task 31963 on cpu 1:
 prb_reserve+0x696/0xaf0 kernel/printk/printk_ringbuffer.c:1635
 vprintk_store+0x56d/0x860 kernel/printk/printk.c:2299
 vprintk_emit+0x10d/0x580 kernel/printk/printk.c:2399
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2438
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2448
 __nla_validate_parse+0x1738/0x1d00 lib/nlattr.c:647
 nla_validate_array lib/nlattr.c:109 [inline]
 validate_nla lib/nlattr.c:536 [inline]
 __nla_validate_parse+0x6a4/0x1d00 lib/nlattr.c:635
 nla_validate_array lib/nlattr.c:109 [inline]
 validate_nla lib/nlattr.c:536 [inline]
 __nla_validate_parse+0x6a4/0x1d00 lib/nlattr.c:635
 __nla_parse+0x40/0x60 lib/nlattr.c:732
 nla_parse_deprecated include/net/netlink.h:736 [inline]
 nfnetlink_rcv_batch net/netfilter/nfnetlink.c:519 [inline]
 nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:649 [inline]
 nfnetlink_rcv+0xb84/0x16c0 net/netfilter/nfnetlink.c:667
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x5c0/0x690 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x142/0x180 net/socket.c:742
 ____sys_sendmsg+0x31e/0x4e0 net/socket.c:2630
 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2684
 __sys_sendmsg net/socket.c:2716 [inline]
 __do_sys_sendmsg net/socket.c:2721 [inline]
 __se_sys_sendmsg net/socket.c:2719 [inline]
 __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2719
 x64_sys_call+0x191e/0x3000 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff868e1608 of 8 bytes by task 31964 on cpu 0:
 desc_read kernel/printk/printk_ringbuffer.c:486 [inline]
 prb_first_seq kernel/printk/printk_ringbuffer.c:1957 [inline]
 _prb_read_valid+0x383/0x920 kernel/printk/printk_ringbuffer.c:2114
 desc_update_last_finalized kernel/printk/printk_ringbuffer.c:1515 [inline]
 prb_final_commit+0x136/0x1e0 kernel/printk/printk_ringbuffer.c:1782
 vprintk_store+0x741/0x860 kernel/printk/printk.c:2325
 vprintk_emit+0x10d/0x580 kernel/printk/printk.c:2399
 vprintk_default+0x26/0x30 kernel/printk/printk.c:2438
 vprintk+0x1d/0x30 kernel/printk/printk_safe.c:82
 _printk+0x79/0xa0 kernel/printk/printk.c:2448
 __nla_validate_parse+0x1738/0x1d00 lib/nlattr.c:647
 nla_validate_array lib/nlattr.c:109 [inline]
 validate_nla lib/nlattr.c:536 [inline]
 __nla_validate_parse+0x6a4/0x1d00 lib/nlattr.c:635
 nla_validate_array lib/nlattr.c:109 [inline]
 validate_nla lib/nlattr.c:536 [inline]
 __nla_validate_parse+0x6a4/0x1d00 lib/nlattr.c:635
 __nla_parse+0x40/0x60 lib/nlattr.c:732
 nla_parse_deprecated include/net/netlink.h:736 [inline]
 nfnetlink_rcv_batch net/netfilter/nfnetlink.c:519 [inline]
 nfnetlink_rcv_skb_batch net/netfilter/nfnetlink.c:649 [inline]
 nfnetlink_rcv+0xb84/0x16c0 net/netfilter/nfnetlink.c:667
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x5c0/0x690 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x58b/0x6b0 net/netlink/af_netlink.c:1896
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg+0x142/0x180 net/socket.c:742
 ____sys_sendmsg+0x31e/0x4e0 net/socket.c:2630
 ___sys_sendmsg+0x17b/0x1d0 net/socket.c:2684
 __sys_sendmsg net/socket.c:2716 [inline]
 __do_sys_sendmsg net/socket.c:2721 [inline]
 __se_sys_sendmsg net/socket.c:2719 [inline]
 __x64_sys_sendmsg+0xd4/0x160 net/socket.c:2719
 x64_sys_call+0x191e/0x3000 arch/x86/include/generated/asm/syscalls_64.h:47
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000002d51 -> 0x0000000000004d51

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 31964 Comm: syz.6.9944 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
==================================================================
netlink: 28 bytes leftover after parsing attributes in process `syz.6.9944'.
netlink: 28 bytes leftover after parsing attributes in process `syz.6.9944'.