stock vmlinux has no symbols

Unless you have compiled your own kernel, you will not have a readily accessible vmlinux, which is an ELF executable. Instead, you will have a compressed kernel in /boot, usually named vmlinuz-<kernel_version>. This compressed kernel image can be decompressed, but the result is a kernel executable that has no symbol table. This poses a problem for forensics analysts or kernel debugging with GDB. The solution for most people in this case is to hope that their Linux distribution has a special package with their kernel version having debug symbols. If so, then they can download a copy of their kernel that has symbols from the distribution repository. In many cases, however, this is not possible, or not convenient for one reason or another. Nonetheless, this problem can be remedied with a custom utility that I designed and released in 2014. This tool is called kdress, because it dresses the kernel symbol table.

Actually, it is named after an old tool by Michael...