cvs commit: src/gnu/usr.bin/gdb/kgdb kgdb.h main.c trgt.c

[John Baldwin]

On Wednesday 23 January 2008 12:33:07 pm Yar Tikhiy wrote:
> On Thu, Jan 17, 2008 at 04:52:30PM -0500, John Baldwin wrote:
> > On Thursday 17 January 2008 04:43:12 pm John Baldwin wrote:
> > > jhb         2008-01-17 21:43:12 UTC
> > > 
> > >   FreeBSD src repository
> > > 
> > >   Modified files:
> > >     gnu/usr.bin/gdb/kgdb kgdb.h main.c trgt.c 
> > >   Log:
> > >   Add a new 'add-kld <kld>' command to kgdb to make it easier to analyze
> > >   crash dumps with kernel modules.  The command is basically a wrapper
> > >   around add-symbol-file except that it uses the kernel linker data
> > >   structures and the ELF section headers of the kld to calculate the
> > >   section addresses add-symbol-file needs.
> > 
> > Forgot to say:
> > 
> > Tested on:	i386, amd64
> > 
> > A sample run on i386:
> > 
> > > sudo ./kgdb -c /usr/crash/vmcore.10 /boot/kernel/kernel
> > ...
> > crash: blow the kernel stack on purpose
> > 
> > Fatal double fault:
> > eip = 0xc05c6220
> > esp = 0xe61b0000
> > ebp = 0xe61b0018
> > panic: double fault
> > KDB: enter: panic
> > ...
> > (kgdb) where
> > #0  doadump () at pcpu.h:195
> > #1  0xc05d399c in boot (howto=260) 
at /usr/src/sys/kern/kern_shutdown.c:417
> > #2  0xc05d3c0a in panic (fmt=Variable "fmt" is not available.
> > ) at /usr/src/sys/kern/kern_shutdown.c:571
> > #3  0xc08115d9 in dblfault_handler () at /usr/src/sys/i386/i386/trap.c:927
> > #4  0xc05c6220 in mtx_pool_setup_dynamic ()
> > #5  0xc065e125 in arc4rand (ptr=0xe61b0168, len=4, reseed=0)
> >     at /usr/src/sys/libkern/arc4random.c:142
> > #6  0xc065e171 in arc4random () at /usr/src/sys/libkern/arc4random.c:150
> > #7  0xc3d43402 in ?? ()
> > #8  0xb15ac28c in ?? ()
> > #9  0x793b5626 in ?? ()
> > #10 0xe61b018c in ?? ()
> > #11 0xc3d43410 in ?? ()
> > #12 0xbc8e58bf in ?? ()
> > ...
> > (kgdb) add-kld crash.ko
> > add symbol table from file "/boot/modules/crash.ko.symbols" at
> >         .text_addr = 0xc3d416f0
> >         .data_addr = 0xc3d44000
> >         .bss_addr = 0xc3d44254
> >         .rodata_addr = 0xc3d4364e
> > Reading symbols from /boot/modules/crash.ko.symbols...done.
> 
> Thank you!
> 
> By the way, if there are a lot of modules to load, using asf(8)
> might be a little easier: one needs to run asf once and then he
> can source its output (written to .asf by default) into the kgdb
> session.  Just a little advertisment so that my work on asf(8)
> doesn't fall into oblivion. :-)
> 
> OTOH, I can imagine `add-all-klds' command for kgdb implemented in
> a similar vein since there is a full list of loaded modules in the
> core image.

Actually, that is my next step is to make the kgdb auto-load all klds it can 
find on startup.  asf(8) does work, but I find it a bit more work to have to 
use an external utility to do it, and potentially more confusing for users.

-- 
John Baldwin