Virtualbox + kgdb: Can't see vmlinux symbols

[Kamran Khan]

I have an Ubuntu 16.04 VM running in Virtualbox.

I'm building kernel from git using make deb-pkg.

After I install all the deb packages (including debug symbols) on the
VM and restart it, I can see in uname -r output that the appropriate
kernel was booted from.

I'm passing the following parameters to the kernel:

> kgdboc=ttyS0,115200 kgdbwait

Once the kernel boots, I am able to connect to it via socat + gdb from host.

I'm using the full uncompressed vmlinux file to start the gdb which
contains all the debugging symbols.

However, I can't see any of the symbols in backtrace etc.

> $ du -sh vmlinux
> 425M vmlinux
> $ gdb vmlinux
> GNU gdb (Ubuntu 7.11.1-0ubuntu1~16.04) 7.11.1
> Copyright (C) 2016 Free Software Foundation, Inc.
> License GPLv3+: GNU GPL version 3 or later [gnu.org]
> [...]
> For help, type "help".
> Type "apropos word" to search for commands related to "word"...
> Reading symbols from vmlinux...done.
> (gdb) target remote /dev/pts/2
> Remote debugging using /dev/pts/2
> 0xffffffffb113c5b4 in ?? ()
> (gdb) bt
> #0  0xffffffffb113c5b4 in ?? ()
> #1  0xffffb035421c7dd0 in ?? ()
> #2  0xffffffffb113c60c in ?? ()
> #3  0xffffb035421c7e00 in ?? ()
> #4  0xffffffffb153035a in ?? ()
> #5  0x0000000000000002 in irq_stack_union ()
> #6  0x00000000013a7408 in ?? ()
> #7  0xffff8fb8bd0d3b00 in ?? ()
> #8  0xffffb035421c7e18 in ?? ()
> #9  0xffffffffb15307df in ?? ()
> #10 0xffff8fb8b8779900 in ?? ()
> #11 0xffffb035421c7e38 in ?? ()
> #12 0xffffffffb12ab412 in ?? ()
> #13 0xffff8fb8bd0d3b00 in ?? ()


Any ideas what am I doing wrong?

Thanks,
Kamran.