[1/2] module: allow for module error injection

Commit Message

Daniel Gomez Jan. 22, 2025, 1:11 p.m. UTC

Allow to test kernel module initialization with eBPF error injection
by forcing errors when any of the below annotated functions with
ALLOW_ERROR_INJECTION() return.

Allow to debug and test module load error behaviour when:

complete_formation(): when module initialization switches from
MODULE_STATE_UNFORMED to MODULE_STATE_COMING stage.

do_init_module(): when an error occurs during module initialization and
before we switch from MODULE_STATE_COMING to MODULE_STATE_LIVE stage.

module_enable_rodata_ro_after_init(): when an error occurs while
setting memory to RO after module initialization. This is when module
initialization reaches MODULE_STATE_LIVE stage.

Signed-off-by: Daniel Gomez <[e-mail]>
---
 kernel/module/main.c       | 3 +++
 kernel/module/strict_rwx.c | 2 ++
 2 files changed, 5 insertions(+)

Patch

diff --git a/kernel/module/main.c b/kernel/module/main.c
index 1fb9ad289a6f8f328fc37c6d93730882d0e6e613..54e6c4d0aab23ae5001a52c26417e7e7957ea3fd 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -59,6 +59,7 @@ 
 #include <linux/codetag.h>
 #include <linux/debugfs.h>
 #include <linux/execmem.h>
+#include <linux/bpf.h>
 #include <uapi/linux/module.h>
 #include "internal.h"
 
@@ -3089,6 +3090,7 @@  static noinline int do_init_module(struct module *mod)
 
 	return ret;
 }
+ALLOW_ERROR_INJECTION(do_init_module, ERRNO);
 
 static int may_init_module(void)
 {
@@ -3225,6 +3227,7 @@  static int complete_formation(struct module *mod, struct load_info *info)
 	mutex_unlock(&module_mutex);
 	return err;
 }
+ALLOW_ERROR_INJECTION(complete_formation, ERRNO);
 
 static int prepare_coming_module(struct module *mod)
 {
diff --git a/kernel/module/strict_rwx.c b/kernel/module/strict_rwx.c
index 74834ba15615fa02d1fa72b913feedd7400af779..21936f5cc1e679e4de90331ef4920597d9093f35 100644
--- a/kernel/module/strict_rwx.c
+++ b/kernel/module/strict_rwx.c
@@ -9,6 +9,7 @@ 
 #include <linux/mm.h>
 #include <linux/vmalloc.h>
 #include <linux/set_memory.h>
+#include <linux/bpf.h>
 #include "internal.h"
 
 static int module_set_memory(const struct module *mod, enum mod_mem_type type,
@@ -71,6 +72,7 @@  int module_enable_rodata_ro_after_init(const struct module *mod)
 
 	return module_set_memory(mod, MOD_RO_AFTER_INIT, set_memory_ro);
 }
+ALLOW_ERROR_INJECTION(module_enable_rodata_ro_after_init, ERRNO);
 
 int module_enable_data_nx(const struct module *mod)
 {