Re: [PATCH v3 12/15] livepatch: store function sizes

[Kamalesh Babulal]

On Thursday 08 December 2016 11:38 PM, Josh Poimboeuf wrote:

For the consistency model we'll need to know the sizes of the old and
new functions to determine if they're on the stacks of any tasks.

Signed-off-by: Josh Poimboeuf 


Reviewed-by: Kamalesh Babulal 

--
cheers,
Kamalesh.

Re: [PATCH v3 12/15] livepatch: store function sizes

[Miroslav Benes]

On Thu, 8 Dec 2016, Josh Poimboeuf wrote:

> For the consistency model we'll need to know the sizes of the old and
> new functions to determine if they're on the stacks of any tasks.
> 
> Signed-off-by: Josh Poimboeuf 

Acked-by: Miroslav Benes 

Miroslav

Re: [PATCH v3 12/15] livepatch: store function sizes

[Petr Mladek]

On Thu 2016-12-08 12:08:37, Josh Poimboeuf wrote:
> For the consistency model we'll need to know the sizes of the old and
> new functions to determine if they're on the stacks of any tasks.
> 
> Signed-off-by: Josh Poimboeuf 

Reviewed-by: Petr Mladek 

Best Regards,
Petr

[PATCH v3 12/15] livepatch: store function sizes

[Josh Poimboeuf]

For the consistency model we'll need to know the sizes of the old and
new functions to determine if they're on the stacks of any tasks.

Signed-off-by: Josh Poimboeuf 
---
 include/linux/livepatch.h |  3 +++
 kernel/livepatch/core.c   | 16 
 2 files changed, 19 insertions(+)

diff --git a/include/linux/livepatch.h b/include/linux/livepatch.h
index 1e2eb91..1a5a93c 100644
--- a/include/linux/livepatch.h
+++ b/include/linux/livepatch.h
@@ -37,6 +37,8 @@
  * @old_addr:  the address of the function being patched
  * @kobj:  kobject for sysfs resources
  * @stack_node:list node for klp_ops func_stack list
+ * @old_size:  size of the old function
+ * @new_size:  size of the new function
  * @patched:   the func has been added to the klp_ops list
  */
 struct klp_func {
@@ -56,6 +58,7 @@ struct klp_func {
unsigned long old_addr;
struct kobject kobj;
struct list_head stack_node;
+   unsigned long old_size, new_size;
bool patched;
 };
 
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 8ca8a0e..fc160c6 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -584,6 +584,22 @@ static int klp_init_object_loaded(struct klp_patch *patch,
 >old_addr);
if (ret)
return ret;
+
+   ret = kallsyms_lookup_size_offset(func->old_addr,
+ >old_size, NULL);
+   if (!ret) {
+   pr_err("kallsyms size lookup failed for '%s'\n",
+  func->old_name);
+   return -ENOENT;
+   }
+
+   ret = kallsyms_lookup_size_offset((unsigned long)func->new_func,
+ >new_size, NULL);
+   if (!ret) {
+   pr_err("kallsyms size lookup failed for '%s' 
replacement\n",
+  func->old_name);
+   return -ENOENT;
+   }
}
 
return 0;
-- 
2.7.4