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Subject[RFC PATCH v1.9 11/14] livepatch: store function sizes
Date
For the consistency model we'll need to know the sizes of the old and
new functions to determine if they're on stacks of any tasks.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.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 6d45dc7..dd5db74 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 beaf263..b0fd31d 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -540,6 +540,22 @@ 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;
--
2.4.3
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