module: Account for the build time module name mangling

Sean noted that scripts/Makefile.lib:name-fix-token rule will mangle
the module name with s/-/_/g.

Since this happens late in the build, only the kernel needs to bother
with this, the modpost tool still sees the original name.

Reported-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

diff --git a/kernel/module/main.c b/kernel/module/main.c
index e4b6968dc3082787eb5c11983033bbf5c388acec..81035f6552ecffce79dc4e99a9a448e4ac7d2376 100644 (file)
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -169,6 +169,30 @@ static inline void add_taint_module(struct module *mod, unsigned flag,
        set_bit(flag, &mod->taints);
 }
 
+/*
+ * Like strncmp(), except s/-/_/g as per scripts/Makefile.lib:name-fix-token rule.
+ */
+static int mod_strncmp(const char *str_a, const char *str_b, size_t n)
+{
+       for (int i = 0; i < n; i++) {
+               char a = str_a[i];
+               char b = str_b[i];
+               int d;
+
+               if (a == '-') a = '_';
+               if (b == '-') b = '_';
+
+               d = a - b;
+               if (d)
+                       return d;
+
+               if (!a)
+                       break;
+       }
+
+       return 0;
+}
+
 /*
  * A thread that wants to hold a reference to a module only while it
  * is running can call this to safely exit.
@@ -1116,7 +1140,7 @@ static bool verify_module_namespace(const char *namespace, const char *modname)
                if (*sep)
                        sep++;
 
-               if (strncmp(namespace, modname, len) == 0 && (glob || len == modlen))
+               if (mod_strncmp(namespace, modname, len) == 0 && (glob || len == modlen))
                        return true;
        }