Modules can have a series of aliases, but we don't currently use
them to check if a module is already loaded. Part of this is because
load_module() will stick to checking for already loaded modules using
the actual module name, not an alias. Its however desriable to also
check for aliases on find_module_all() for existing callers and future
callers. The curent gain to using aliases on find_module_all() will
simply be to be able to support unloading modules using the alias using
the delete_module() syscall.
You can debug this with dynamic debug:
GRUB_CMDLINE_LINUX_DEFAULT="dyndbg=\"func module_process_aliases +p; func module_name_match +p; \" "
Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
---
kernel/module/aliases.c | 17 +++++++++++++++++
kernel/module/internal.h | 5 +++++
kernel/module/main.c | 24 +++++++++++++++++++++++-
3 files changed, 45 insertions(+), 1 deletion(-)
diff --git a/kernel/module/aliases.c b/kernel/module/aliases.c
index 2f30c9d4c765..69518bc5169a 100644
--- a/kernel/module/aliases.c
+++ b/kernel/module/aliases.c
@@ -90,3 +90,20 @@ int module_process_aliases(struct module *mod, struct load_info *info)
return -ENOMEM;
}
+
+bool module_name_match_aliases(struct module *mod, const char *name, size_t len)
+{
+ unsigned int i;
+ const char *alias;
+
+ for (i=0; i < mod->num_aliases; i++) {
+ alias = mod->aliases[i];
+ if (strlen(alias) == len && !memcmp(alias, name, len)) {
+ pr_debug("module %s alias matched: alias[%u] = %s\n",
+ mod->name, i, alias);
+ return true;
+ }
+ }
+
+ return false;
+}
diff --git a/kernel/module/internal.h b/kernel/module/internal.h
index 40bb80ed21e2..78aaad74f4ca 100644
--- a/kernel/module/internal.h
+++ b/kernel/module/internal.h
@@ -306,6 +306,7 @@ static inline int same_magic(const char *amagic, const char *bmagic, bool has_cr
#ifdef CONFIG_MODULE_KERNEL_ALIAS
void free_mod_aliases(struct module *mod);
int module_process_aliases(struct module *mod, struct load_info *info);
+bool module_name_match_aliases(struct module *mod, const char *name, size_t len);
#else
static void free_mod_aliases(struct module *mod)
{
@@ -314,4 +315,8 @@ static int module_process_aliases(struct module *mod, struct load_info *info)
{
return 0;
}
+static bool module_name_match_aliases(struct module *mod, const char *name, size_t len)
+{
+ return false;
+}
#endif /* CONFIG_MODULE_KERNEL_ALIAS */
diff --git a/kernel/module/main.c b/kernel/module/main.c
index bc9202b60d55..cf044329da3c 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -338,6 +338,28 @@ bool find_symbol(struct find_symbol_arg *fsa)
return false;
}
+static bool module_name_match(struct module *mod, const char *name, size_t len)
+{
+ unsigned int i;
+ const char *alias;
+
+ if (strlen(mod->name) == len && !memcmp(mod->name, name, len))
+ return true;
+
+ return module_name_match_aliases(mod, name, len);
+
+ for (i=0; i < mod->num_aliases; i++) {
+ alias = mod->aliases[i];
+ if (strlen(alias) == len && !memcmp(alias, name, len)) {
+ pr_debug("module %s alias matched: alias[%u] = %s\n",
+ mod->name, i, alias);
+ return true;
+ }
+ }
+
+ return false;
+}
+
/*
* Search for module by name: must hold module_mutex (or preempt disabled
* for read-only access).
@@ -353,7 +375,7 @@ struct module *find_module_all(const char *name, size_t len,
lockdep_is_held(&module_mutex)) {
if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
continue;
- if (strlen(mod->name) == len && !memcmp(mod->name, name, len))
+ if (module_name_match(mod, name, len))
return mod;
}
return NULL;
--
2.39.1
