[PATCH v5 12/15] livepatch: store function sizes
Josh Poimboeuf
jpoimboe at redhat.com
Tue Feb 14 12:42:39 AEDT 2017
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 <jpoimboe at redhat.com>
Acked-by: Miroslav Benes <mbenes at suse.cz>
Reviewed-by: Petr Mladek <pmladek at suse.com>
Reviewed-by: Kamalesh Babulal <kamalesh at linux.vnet.ibm.com>
---
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 9787a63..6602b34 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 83c4949..10ba3a1 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,
&func->old_addr);
if (ret)
return ret;
+
+ ret = kallsyms_lookup_size_offset(func->old_addr,
+ &func->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,
+ &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
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