What use is the kernel-debuginfo package?

[Roland McGrath]

> Well, addr2line works because you point it directly to the .ko.debug file:
> 
> $ eu-addr2line -e ahci.ko.debug 0x0
> drivers/ata/ahci.c:479

That does not necessarily work, because it may not be able to do enough
relocation.  -e /installed/stripped/file, -k, -K, -p PID work, and they
find the debuginfo file for you.  (For ET_REL files you need to add 0x10000
to the address you use if using elfutils < 0.126.)

> But how could gdb put the two separate files together when there is no
> connection between them? How could it possibly know to go from:
> 
>   /lib/modules/2.6.20-1.2925.fc6/kernel/drivers/ata/ahci.ko
> 
> to
> 
>   /usr/lib/debug/lib/modules/2.6.20-1.2925.fc6/kernel/drivers/ata/ahci.ko.debug

Lo and behold, it does work.  Really, truly.  Embedding directory names is
Not The Way.  (Try "help set debug-file-directory" in gdb.  The elfutils
tools and their --debuginfo-path option are similar.)