powerpc/kprobes: Handle error returned by set_memory_rox()

set_memory_rox() can fail.

In case it fails, free allocated memory and return NULL.

Link: KSPP#7
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/b4907cf4339bd086abc40430d91311436cb0c18e.1708078401.git.christophe.leroy@csgroup.eu

Author: chleroy

arch/powerpc/kernel/kprobes.c

@@ -134,10 +134,16 @@ void *alloc_insn_page(void)
 	if (!page)
 		return NULL;
 
-	if (strict_module_rwx_enabled())
-		set_memory_rox((unsigned long)page, 1);
+	if (strict_module_rwx_enabled()) {
+		int err = set_memory_rox((unsigned long)page, 1);
 
+		if (err)
+			goto error;
+	}
 	return page;
+error:
+	module_memfree(page);
+	return NULL;
 }
 
 int arch_prepare_kprobe(struct kprobe *p)