Fix depmod issue found in rust-next

We only need the symbol length increase, not the module
prefix one.

Reported-by: Heiko Carstens <[email protected]>
Reported-by: Daniel Axtens <[email protected]>
Signed-off-by: Miguel Ojeda <[email protected]>

Author: ojeda

include/linux/moduleparam.h

@@ -18,7 +18,7 @@
 #endif
 
 /* Chosen so that structs with an unsigned long line up. */
-#define MAX_PARAM_PREFIX_LEN (256 - sizeof(unsigned long))
+#define MAX_PARAM_PREFIX_LEN (64 - sizeof(unsigned long))
 
 #define __MODULE_INFO(tag, name, info)					  \
 	static const char __UNIQUE_ID(name)[]				  \

kernel/livepatch/core.c

@@ -210,10 +210,10 @@ static int klp_resolve_symbols(Elf64_Shdr *sechdrs, const char *strtab,
 	 * and KSYM_NAME_LEN have the values we expect them to have.
 	 *
 	 * Because the value of MODULE_NAME_LEN can differ among architectures,
-	 * we use the smallest/strictest upper bound possible (248, based on
+	 * we use the smallest/strictest upper bound possible (56, based on
 	 * the current definition of MODULE_NAME_LEN) to prevent overflows.
 	 */
-	BUILD_BUG_ON(MODULE_NAME_LEN < 248 || KSYM_NAME_LEN != 512);
+	BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 512);
 
 	relas = (Elf_Rela *) relasec->sh_addr;
 	/* For each rela in this klp relocation section */
@@ -227,7 +227,7 @@ static int klp_resolve_symbols(Elf64_Shdr *sechdrs, const char *strtab,
 
 		/* Format: .klp.sym.sym_objname.sym_name,sympos */
 		cnt = sscanf(strtab + sym->st_name,
-			     ".klp.sym.%247[^.].%511[^,],%lu",
+			     ".klp.sym.%55[^.].%511[^,],%lu",
 			     sym_objname, sym_name, &sympos);
 		if (cnt != 3) {
 			pr_err("symbol %s has an incorrectly formatted name\n",