+++ Miroslav Benes [28/04/16 16:34 +0200]:
Current object-walking helper checks the presence of obj->funcs to
determine the end of objs array in klp_object structure. This is
somewhat fragile because one can easily forget about funcs definition
during livepatch creation. In such a case the livepatch module is
successfully loaded and all objects after the incorrect one are omitted.
This is very confusing. Let's make the helper more robust and check also
for the other external member, name. Thus the helper correctly stops on
an empty item of the array. We need to have a check for obj->funcs in
klp_init_object() to make it work.
The same applies to a func-walking helper.
As a benefit we'll check for new_func member definition during the
livepatch initialization. There is no such check anywhere in the code
now.
Signed-off-by: Miroslav Benes <mbenes@xxxxxxx>
---
include/linux/livepatch.h | 6 ++++--
kernel/livepatch/core.c | 3 +++
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
index 0933ca47791c..a93a0b23dc8d 100644
--- a/include/linux/livepatch.h
+++ b/include/linux/livepatch.h
@@ -104,10 +104,12 @@ struct klp_patch {
};
#define klp_for_each_object(patch, obj) \
- for (obj = patch->objs; obj->funcs; obj++)
+ for (obj = patch->objs; obj->funcs || obj->name; obj++)
Remember that for patches to vmlinux, obj->name and obj->mod will also
both be NULL. So if someone happens to forget to fill in obj->funcs
for a vmlinux patch, we won't catch that case here. Perhaps we need a
better way of determining whether we've reached the end of the array,
or determining that the struct is truly empty..
Jessica
--
To unsubscribe from this list: send the line "unsubscribe live-patching" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
