Modules fixes for v5.4-rc3

- Fix broken external module builds due to a modpost bug in read_dump(),
   where the namespace was not being strdup'd and sym->namespace would be
   set to bogus data.
 - Various namespace-related kbuild fixes and cleanups thanks to
   Masahiro Yamada.
 
 Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Merge tag 'modules-for-v5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux

Pull module fixes from Jessica Yu:
 "Code cleanups and kbuild/namespace related fixups from Masahiro.

  Most importantly, it fixes a namespace-related modpost issue for
  external module builds

   - Fix broken external module builds due to a modpost bug in
     read_dump(), where the namespace was not being strdup'd and
     sym->namespace would be set to bogus data.

   - Various namespace-related kbuild fixes and cleanups thanks to
     Masahiro Yamada"

* tag 'modules-for-v5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
  doc: move namespaces.rst from kbuild/ to core-api/
  nsdeps: make generated patches independent of locale
  nsdeps: fix hashbang of scripts/nsdeps
  kbuild: fix build error of 'make nsdeps' in clean tree
  module: rename __kstrtab_ns_* to __kstrtabns_* to avoid symbol conflict
  modpost: fix broken sym->namespace for external module builds
  module: swap the order of symbol.namespace
  scripts: add_namespace: Fix coccicheck failed

Documentation/core-api/index.rst

@@ -38,6 +38,7 @@ Core utilities
    protection-keys
    ../RCU/index
    gcc-plugins
+   symbol-namespaces
 
 
 Interfaces for kernel debugging

MAINTAINERS

@@ -11544,6 +11544,7 @@ NSDEPS
 M:	Matthias Maennich <maennich@google.com>
 S:	Maintained
 F:	scripts/nsdeps
+F:	Documentation/core-api/symbol-namespaces.rst
 
 NTB AMD DRIVER
 M:	Shyam Sundar S K <Shyam-sundar.S-k@amd.com>

Makefile

@@ -599,7 +599,7 @@ endif
 # in addition to whatever we do anyway.
 # Just "make" or "make all" shall build modules as well
 
-ifneq ($(filter all _all modules,$(MAKECMDGOALS)),)
+ifneq ($(filter all _all modules nsdeps,$(MAKECMDGOALS)),)
   KBUILD_MODULES := 1
 endif
 

include/linux/export.h

@@ -52,10 +52,10 @@ extern struct module __this_module;
 	__ADDRESSABLE(sym)						\
 	asm("	.section \"___ksymtab" sec "+" #sym "\", \"a\"	\n"	\
 	    "	.balign	4					\n"	\
-	    "__ksymtab_" #sym NS_SEPARATOR #ns ":		\n"	\
+	    "__ksymtab_" #ns NS_SEPARATOR #sym ":		\n"	\
 	    "	.long	" #sym "- .				\n"	\
 	    "	.long	__kstrtab_" #sym "- .			\n"	\
-	    "	.long	__kstrtab_ns_" #sym "- .		\n"	\
+	    "	.long	__kstrtabns_" #sym "- .			\n"	\
 	    "	.previous					\n")
 
 #define __KSYMTAB_ENTRY(sym, sec)					\
@@ -76,10 +76,10 @@ struct kernel_symbol {
 #else
 #define __KSYMTAB_ENTRY_NS(sym, sec, ns)				\
 	static const struct kernel_symbol __ksymtab_##sym##__##ns	\
-	asm("__ksymtab_" #sym NS_SEPARATOR #ns)				\
+	asm("__ksymtab_" #ns NS_SEPARATOR #sym)				\
 	__attribute__((section("___ksymtab" sec "+" #sym), used))	\
 	__aligned(sizeof(void *))					\
-	= { (unsigned long)&sym, __kstrtab_##sym, __kstrtab_ns_##sym }
+	= { (unsigned long)&sym, __kstrtab_##sym, __kstrtabns_##sym }
 
 #define __KSYMTAB_ENTRY(sym, sec)					\
 	static const struct kernel_symbol __ksymtab_##sym		\
@@ -112,7 +112,7 @@ struct kernel_symbol {
 /* For every exported symbol, place a struct in the __ksymtab section */
 #define ___EXPORT_SYMBOL_NS(sym, sec, ns)				\
 	___export_symbol_common(sym, sec);				\
-	static const char __kstrtab_ns_##sym[]				\
+	static const char __kstrtabns_##sym[]				\
 	__attribute__((section("__ksymtab_strings"), used, aligned(1)))	\
 	= #ns;								\
 	__KSYMTAB_ENTRY_NS(sym, sec, ns)

scripts/coccinelle/misc/add_namespace.cocci

@@ -6,6 +6,8 @@
 /// add a missing namespace tag to a module source file.
 ///
 
+virtual report
+
 @has_ns_import@
 declarer name MODULE_IMPORT_NS;
 identifier virtual.ns;

scripts/mod/modpost.c

@@ -166,7 +166,7 @@ struct symbol {
 	struct module *module;
 	unsigned int crc;
 	int crc_valid;
-	const char *namespace;
+	char *namespace;
 	unsigned int weak:1;
 	unsigned int vmlinux:1;    /* 1 if symbol is defined in vmlinux */
 	unsigned int kernel:1;     /* 1 if symbol is from kernel
@@ -348,20 +348,18 @@ static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
 		return export_unknown;
 }
 
-static const char *sym_extract_namespace(const char **symname)
+static char *sym_extract_namespace(const char **symname)
 {
-	size_t n;
-	char *dupsymname;
+	char *namespace = NULL;
+	char *ns_separator;
 
-	n = strcspn(*symname, ".");
-	if (n < strlen(*symname) - 1) {
-		dupsymname = NOFAIL(strdup(*symname));
-		dupsymname[n] = '\0';
-		*symname = dupsymname;
-		return dupsymname + n + 1;
+	ns_separator = strchr(*symname, '.');
+	if (ns_separator) {
+		namespace = NOFAIL(strndup(*symname, ns_separator - *symname));
+		*symname = ns_separator + 1;
 	}
 
-	return NULL;
+	return namespace;
 }
 
 /**
@@ -375,7 +373,6 @@ static struct symbol *sym_add_exported(const char *name, const char *namespace,
 
 	if (!s) {
 		s = new_symbol(name, mod, export);
-		s->namespace = namespace;
 	} else {
 		if (!s->preloaded) {
 			warn("%s: '%s' exported twice. Previous export was in %s%s\n",
@@ -386,6 +383,8 @@ static struct symbol *sym_add_exported(const char *name, const char *namespace,
 			s->module = mod;
 		}
 	}
+	free(s->namespace);
+	s->namespace = namespace ? strdup(namespace) : NULL;
 	s->preloaded = 0;
 	s->vmlinux   = is_vmlinux(mod->name);
 	s->kernel    = 0;
@@ -672,7 +671,8 @@ static void handle_modversions(struct module *mod, struct elf_info *info,
 	unsigned int crc;
 	enum export export;
 	bool is_crc = false;
-	const char *name, *namespace;
+	const char *name;
+	char *namespace;
 
 	if ((!is_vmlinux(mod->name) || mod->is_dot_o) &&
 	    strstarts(symname, "__ksymtab"))
@@ -747,6 +747,7 @@ static void handle_modversions(struct module *mod, struct elf_info *info,
 			name = symname + strlen("__ksymtab_");
 			namespace = sym_extract_namespace(&name);
 			sym_add_exported(name, namespace, mod, export);
+			free(namespace);
 		}
 		if (strcmp(symname, "init_module") == 0)
 			mod->has_init = 1;
@@ -2195,7 +2196,7 @@ static int check_exports(struct module *mod)
 		else
 			basename = mod->name;
 
-		if (exp->namespace) {
+		if (exp->namespace && exp->namespace[0]) {
 			add_namespace(&mod->required_namespaces,
 				      exp->namespace);
 

scripts/nsdeps

@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 # SPDX-License-Identifier: GPL-2.0
 # Linux kernel symbol namespace import generator
 #
@@ -41,7 +41,7 @@ generate_deps() {
 		for source_file in $mod_source_files; do
 			sed '/MODULE_IMPORT_NS/Q' $source_file > ${source_file}.tmp
 			offset=$(wc -l ${source_file}.tmp | awk '{print $1;}')
-			cat $source_file | grep MODULE_IMPORT_NS | sort -u >> ${source_file}.tmp
+			cat $source_file | grep MODULE_IMPORT_NS | LANG=C sort -u >> ${source_file}.tmp
 			tail -n +$((offset +1)) ${source_file} | grep -v MODULE_IMPORT_NS >> ${source_file}.tmp
 			if ! diff -q ${source_file} ${source_file}.tmp; then
 				mv ${source_file}.tmp ${source_file}