Re: [Crash-utility] Loading debuginfo symbols
----- Original Message -----
Hi,
I would like to be able to load symbols from a specific debuginfo directory using
'mod -S <dir>'. This works if you unpack the corresponding kernel rpm too
but I'd
like to be able to save on the disk space by just using the debuginfo rpm. This
currently doesn't work because crash doesn't explicitly search for modules
ending
in .ko.debug. The simple patch below adds this support. Is this a sensible change
to make or is there a better way to do this?
Lachlan
It's not only sensible -- I've already got a similar patch queued for 6.0.1!
Here's the changelog entry:
- If the "--mod <directory-tree>" command line option, or the
setting of the CRASH_MODULE_PATH environment variable, or the
"mod -S <directory-tree>" point to a tree that contains only
the
separate debuginfo "<module>.ko.debug" files, then those
debuginfo files will be used as the internal "add-symbol-file"
arguments to the embedded gdb module. Without the patch, it was
only acceptable to point to a directory tree that contained the
base "<module>.ko" files, and the separate debuginfo files
were found automatically based upon the directory path to the
base module file. This will allow an alternate module-debuginfo
directory tree to be set up like so:
# cd <directory>
# rpm2cpio kernel-debuginfo-<release>.rpm | cpio -idv
Having done that, the <directory> may be used with the
"--mod",
command line argument, or as the CRASH_MODULE_PATH environment
variable, or as the "mod -S <directory> argument.
(anderson(a)redhat.com)
It works OK for x86, x86_64 and ppc64 anyway -- although it seems to me that
in the distant past (perhaps with an earlier version of gdb?), that it did
*not* work. But if it does, it certainly makes housekeeping easier.
Be also aware that x86 and x86_64 line number capability is also spotty with
crash-6.0.0 due to changes in the way gdb-7.3.1 handles them. But I've got
6.0.1 fixes queued for those issues as well.
Dave
diff -up crash-5.1.9/kernel.c.orig crash-5.1.9/kernel.c
--- crash-5.1.9/kernel.c.orig 2011-11-08 14:15:51.467399576 +1100
+++ crash-5.1.9/kernel.c 2011-11-09 14:26:23.264253341 +1100
@@ -3588,7 +3588,10 @@ module_objfile_search(char *modref, char
{
case KMOD_V2:
sprintf(file, "%s.ko", modref);
- retbuf = search_directory_tree(tree, file, 1);
+ if (!(retbuf = search_directory_tree(tree, file, 1))) {
+ sprintf(file, "%s.ko.debug", modref);
+ retbuf = search_directory_tree(tree, file, 1);
+ }
}
}
return retbuf;
@@ -3605,7 +3608,10 @@ module_objfile_search(char *modref, char
{
case KMOD_V2:
sprintf(file, "%s.ko", modref);
- retbuf = search_directory_tree(dir, file, 0);
+ if (!(retbuf = search_directory_tree(dir, file, 0))) {
+ sprintf(file, "%s.ko.debug", modref);
+ retbuf = search_directory_tree(dir, file, 0);
+ }
}
}
}
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