=====================================================
BUG: KMSAN: uninit-value in check_pointer lib/vsprintf.c:705 [inline]
BUG: KMSAN: uninit-value in string+0x3cf/0x6f0 lib/vsprintf.c:717
 check_pointer lib/vsprintf.c:705 [inline]
 string+0x3cf/0x6f0 lib/vsprintf.c:717
 vsnprintf+0x2222/0x3650 lib/vsprintf.c:2805
 seq_vprintf fs/seq_file.c:391 [inline]
 seq_printf+0x314/0x4f0 fs/seq_file.c:406
 arp_format_neigh_entry net/ipv4/arp.c:1382 [inline]
 arp_seq_show+0x18d5/0x1cc0 net/ipv4/arp.c:1411
 traverse+0x345/0xd70 fs/seq_file.c:111
 seq_read_iter+0x1d47/0x2150 fs/seq_file.c:195
 seq_read+0x7a6/0x990 fs/seq_file.c:162
 pde_read fs/proc/inode.c:311 [inline]
 proc_reg_read+0x39d/0x560 fs/proc/inode.c:323
 do_iter_read+0xb28/0x14c0 fs/read_write.c:788
 vfs_readv fs/read_write.c:906 [inline]
 do_preadv+0x45e/0x6c0 fs/read_write.c:998
 __do_compat_sys_preadv fs/read_write.c:1104 [inline]
 __se_compat_sys_preadv fs/read_write.c:1098 [inline]
 __ia32_compat_sys_preadv+0x166/0x1c0 fs/read_write.c:1098
 do_syscall_32_irqs_on arch/x86/entry/common.c:114 [inline]
 __do_fast_syscall_32+0x96/0xf0 arch/x86/entry/common.c:180
 do_fast_syscall_32+0x34/0x70 arch/x86/entry/common.c:205
 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:248
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c

Local variable buf created at:
 nla_put_ifalias+0x74/0x1c0 net/core/rtnetlink.c:1557
 rtnl_fill_ifinfo+0x1ae4/0x3340 net/core/rtnetlink.c:1738

CPU: 0 PID: 24704 Comm: syz-executor.4 Not tainted 5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
=====================================================