[Crash-utility] Fix for kmem -p
The struct page has been changed to use an unnamed struct inside a
union. Gdb can't determine the offset of members of this unnamed
structure. This broke the kmem -p command in crash. I am pursuing a
fix from the gdb folks, but I am not convinced they will accept this as
a bug:) In this patch, if the offset of page->mapping can't be found
directly I calculate it. If the order of the elements in struct page
should change this will break again, but I cant figure out what else to do.
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gdb has a problem with unnamed structures in a union. The offset for
page->mapping can't be found breaking the "kmem -p" command. I use a
alternate way to find the offset. Ugly, but works.
Signed-off-by: David Wilder <dwilder(a)us.ibm.com>
--- memory.c.orig 2006-02-16 16:03:17.000000000 -0800
+++ memory.c 2006-02-16 17:30:01.000000000 -0800
@@ -236,6 +236,14 @@
MEMBER_OFFSET_INIT(page_count, "page", "_count");
MEMBER_OFFSET_INIT(page_flags, "page", "flags");
MEMBER_OFFSET_INIT(page_mapping, "page", "mapping");
+ /* gdb is having a problem with unnamed structures in a union
+ * The following "hack" works around this problem. */
+ if ( !VALID_MEMBER(page_mapping) ){
+ MEMBER_OFFSET_INIT(page_mapping, "page",
"_mapcount");
+ ASSIGN_OFFSET(page_mapping) =
+ MEMBER_OFFSET("page","_mapcount") +
+ MEMBER_SIZE("struct page","_mapcount");
+ }
MEMBER_OFFSET_INIT(page_index, "page", "index");
MEMBER_OFFSET_INIT(page_buffers, "page", "buffers");
MEMBER_OFFSET_INIT(page_lru, "page", "lru");
-------------------------
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David Wilder
IBM Linux Technology Center
Beaverton, Oregon, USA
dwilder(a)us.ibm.com
(503)578-3789