Modules updates for v5.12

Summary of modules changes for the 5.12 merge window:
 
 - Retire EXPORT_UNUSED_SYMBOL() and EXPORT_SYMBOL_GPL_FUTURE(). These export
   types were introduced between 2006 - 2008. All the of the unused symbols have
   been long removed and gpl future symbols were converted to gpl quite a long
   time ago, and I don't believe these export types have been used ever since.
   So, I think it should be safe to retire those export types now. (Christoph Hellwig)
 
 - Refactor and clean up some aged code cruft in the module loader (Christoph Hellwig)
 
 - Build {,module_}kallsyms_on_each_symbol only when livepatching is enabled, as
   it is the only caller (Christoph Hellwig)
 
 - Unexport find_module() and module_mutex and fix the last module
   callers to not rely on these anymore. Make module_mutex internal to
   the module loader. (Christoph Hellwig)
 
 - Harden ELF checks on module load and validate ELF structures before checking
   the module signature (Frank van der Linden)
 
 - Fix undefined symbol warning for clang (Fangrui Song)
 
 - Fix smatch warning (Dan Carpenter)
 
 Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Merge tag 'modules-for-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux

Pull module updates from Jessica Yu:

 - Retire EXPORT_UNUSED_SYMBOL() and EXPORT_SYMBOL_GPL_FUTURE(). These
   export types were introduced between 2006 - 2008. All the of the
   unused symbols have been long removed and gpl future symbols were
   converted to gpl quite a long time ago, and I don't believe these
   export types have been used ever since. So, I think it should be safe
   to retire those export types now (Christoph Hellwig)

 - Refactor and clean up some aged code cruft in the module loader
   (Christoph Hellwig)

 - Build {,module_}kallsyms_on_each_symbol only when livepatching is
   enabled, as it is the only caller (Christoph Hellwig)

 - Unexport find_module() and module_mutex and fix the last module
   callers to not rely on these anymore. Make module_mutex internal to
   the module loader (Christoph Hellwig)

 - Harden ELF checks on module load and validate ELF structures before
   checking the module signature (Frank van der Linden)

 - Fix undefined symbol warning for clang (Fangrui Song)

 - Fix smatch warning (Dan Carpenter)

* tag 'modules-for-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
  module: potential uninitialized return in module_kallsyms_on_each_symbol()
  module: remove EXPORT_UNUSED_SYMBOL*
  module: remove EXPORT_SYMBOL_GPL_FUTURE
  module: move struct symsearch to module.c
  module: pass struct find_symbol_args to find_symbol
  module: merge each_symbol_section into find_symbol
  module: remove each_symbol_in_section
  module: mark module_mutex static
  kallsyms: only build {,module_}kallsyms_on_each_symbol when required
  kallsyms: refactor {,module_}kallsyms_on_each_symbol
  module: use RCU to synchronize find_module
  module: unexport find_module and module_mutex
  drm: remove drm_fb_helper_modinit
  powerpc/powernv: remove get_cxl_module
  module: harden ELF info handling
  module: Ignore _GLOBAL_OFFSET_TABLE_ when warning for undefined symbols

arch/arm/configs/bcm2835_defconfig

@@ -176,7 +176,6 @@ CONFIG_BOOT_PRINTK_DELAY=y
 CONFIG_DYNAMIC_DEBUG=y
 CONFIG_DEBUG_INFO=y
 # CONFIG_ENABLE_MUST_CHECK is not set
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_DEBUG_MEMORY_INIT=y
 CONFIG_LOCKUP_DETECTOR=y
 CONFIG_SCHED_TRACER=y

arch/arm/configs/mxs_defconfig

@@ -164,7 +164,6 @@ CONFIG_FONTS=y
 CONFIG_PRINTK_TIME=y
 CONFIG_DEBUG_INFO=y
 CONFIG_FRAME_WARN=2048
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_KERNEL=y
 CONFIG_SOFTLOCKUP_DETECTOR=y

arch/mips/configs/nlm_xlp_defconfig

@@ -549,7 +549,6 @@ CONFIG_PRINTK_TIME=y
 CONFIG_DEBUG_INFO=y
 # CONFIG_ENABLE_MUST_CHECK is not set
 CONFIG_FRAME_WARN=1024
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_DEBUG_MEMORY_INIT=y
 CONFIG_DETECT_HUNG_TASK=y
 CONFIG_SCHEDSTATS=y

arch/mips/configs/nlm_xlr_defconfig

@@ -500,7 +500,6 @@ CONFIG_CRC7=m
 CONFIG_PRINTK_TIME=y
 CONFIG_DEBUG_INFO=y
 # CONFIG_ENABLE_MUST_CHECK is not set
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_DEBUG_MEMORY_INIT=y
 CONFIG_DETECT_HUNG_TASK=y
 CONFIG_SCHEDSTATS=y

arch/parisc/configs/generic-32bit_defconfig

@@ -22,7 +22,6 @@ CONFIG_PCI_LBA=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_MODULE_FORCE_UNLOAD=y
-CONFIG_UNUSED_SYMBOLS=y
 # CONFIG_BLK_DEV_BSG is not set
 # CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
 CONFIG_BINFMT_MISC=m

arch/parisc/configs/generic-64bit_defconfig

@@ -31,7 +31,6 @@ CONFIG_MODULE_FORCE_LOAD=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_MODULE_FORCE_UNLOAD=y
 CONFIG_MODVERSIONS=y
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_BLK_DEV_INTEGRITY=y
 CONFIG_BINFMT_MISC=m
 # CONFIG_COMPACTION is not set

arch/powerpc/configs/ppc6xx_defconfig

@@ -1071,7 +1071,6 @@ CONFIG_NLS_ISO8859_15=m
 CONFIG_NLS_KOI8_R=m
 CONFIG_NLS_KOI8_U=m
 CONFIG_DEBUG_INFO=y
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_HEADERS_INSTALL=y
 CONFIG_MAGIC_SYSRQ=y
 CONFIG_DEBUG_KERNEL=y

arch/powerpc/platforms/powernv/pci-cxl.c

@@ -150,25 +150,3 @@ int pnv_cxl_ioda_msi_setup(struct pci_dev *dev, unsigned int hwirq,
 	return 0;
 }
 EXPORT_SYMBOL(pnv_cxl_ioda_msi_setup);
-
-#if IS_MODULE(CONFIG_CXL)
-static inline int get_cxl_module(void)
-{
-	struct module *cxl_module;
-
-	mutex_lock(&module_mutex);
-
-	cxl_module = find_module("cxl");
-	if (cxl_module)
-		__module_get(cxl_module);
-
-	mutex_unlock(&module_mutex);
-
-	if (!cxl_module)
-		return -ENODEV;
-
-	return 0;
-}
-#else
-static inline int get_cxl_module(void) { return 0; }
-#endif

arch/s390/configs/debug_defconfig

@@ -71,7 +71,6 @@ CONFIG_MODULE_FORCE_UNLOAD=y
 CONFIG_MODVERSIONS=y
 CONFIG_MODULE_SRCVERSION_ALL=y
 CONFIG_MODULE_SIG_SHA256=y
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_BLK_DEV_INTEGRITY=y
 CONFIG_BLK_DEV_THROTTLING=y
 CONFIG_BLK_WBT=y

arch/s390/configs/defconfig

@@ -66,7 +66,6 @@ CONFIG_MODULE_FORCE_UNLOAD=y
 CONFIG_MODVERSIONS=y
 CONFIG_MODULE_SRCVERSION_ALL=y
 CONFIG_MODULE_SIG_SHA256=y
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_BLK_DEV_THROTTLING=y
 CONFIG_BLK_WBT=y
 CONFIG_BLK_CGROUP_IOLATENCY=y

arch/sh/configs/edosk7760_defconfig

@@ -102,7 +102,6 @@ CONFIG_NLS_UTF8=y
 CONFIG_PRINTK_TIME=y
 # CONFIG_ENABLE_MUST_CHECK is not set
 CONFIG_MAGIC_SYSRQ=y
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_DEBUG_KERNEL=y
 CONFIG_DEBUG_SHIRQ=y
 CONFIG_DETECT_HUNG_TASK=y

arch/sh/configs/sdk7780_defconfig

@@ -128,7 +128,6 @@ CONFIG_NLS_ISO8859_15=y
 CONFIG_NLS_UTF8=y
 # CONFIG_ENABLE_MUST_CHECK is not set
 CONFIG_MAGIC_SYSRQ=y
-CONFIG_UNUSED_SYMBOLS=y
 CONFIG_DEBUG_KERNEL=y
 CONFIG_DETECT_HUNG_TASK=y
 # CONFIG_SCHED_DEBUG is not set

arch/x86/configs/i386_defconfig

@@ -50,7 +50,6 @@ CONFIG_JUMP_LABEL=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_MODULE_FORCE_UNLOAD=y
-# CONFIG_UNUSED_SYMBOLS is not set
 CONFIG_BINFMT_MISC=y
 CONFIG_NET=y
 CONFIG_PACKET=y

arch/x86/configs/x86_64_defconfig

@@ -48,7 +48,6 @@ CONFIG_JUMP_LABEL=y
 CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 CONFIG_MODULE_FORCE_UNLOAD=y
-# CONFIG_UNUSED_SYMBOLS is not set
 CONFIG_BINFMT_MISC=y
 CONFIG_NET=y
 CONFIG_PACKET=y

arch/x86/tools/relocs.c

@@ -61,8 +61,8 @@ static const char * const sym_regex_kernel[S_NSYMTYPES] = {
 	"(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
 	"__(start|end)_pci_.*|"
 	"__(start|end)_builtin_fw|"
-	"__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
+	"__(start|stop)___ksymtab(|_gpl)|"
-	"__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
+	"__(start|stop)___kcrctab(|_gpl)|"
 	"__(start|stop)___param|"
 	"__(start|stop)___modver|"
 	"__(start|stop)___bug_table|"

drivers/gpu/drm/drm_crtc_helper_internal.h

@@ -32,16 +32,6 @@
 #include <drm/drm_encoder.h>
 #include <drm/drm_modes.h>
 
-/* drm_fb_helper.c */
-#ifdef CONFIG_DRM_FBDEV_EMULATION
-int drm_fb_helper_modinit(void);
-#else
-static inline int drm_fb_helper_modinit(void)
-{
-	return 0;
-}
-#endif
-
 /* drm_dp_aux_dev.c */
 #ifdef CONFIG_DRM_DP_AUX_CHARDEV
 int drm_dp_aux_dev_init(void);

drivers/gpu/drm/drm_fb_helper.c

@@ -2514,24 +2514,3 @@ void drm_fbdev_generic_setup(struct drm_device *dev,
 	drm_client_register(&fb_helper->client);
 }
 EXPORT_SYMBOL(drm_fbdev_generic_setup);
-
-/* The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EXPERT)
- * but the module doesn't depend on any fb console symbols.  At least
- * attempt to load fbcon to avoid leaving the system without a usable console.
- */
-int __init drm_fb_helper_modinit(void)
-{
-#if defined(CONFIG_FRAMEBUFFER_CONSOLE_MODULE) && !defined(CONFIG_EXPERT)
-	const char name[] = "fbcon";
-	struct module *fbcon;
-
-	mutex_lock(&module_mutex);
-	fbcon = find_module(name);
-	mutex_unlock(&module_mutex);
-
-	if (!fbcon)
-		request_module_nowait(name);
-#endif
-	return 0;
-}
-EXPORT_SYMBOL(drm_fb_helper_modinit);

drivers/gpu/drm/drm_kms_helper_common.c

@@ -64,19 +64,18 @@ MODULE_PARM_DESC(edid_firmware,
 
 static int __init drm_kms_helper_init(void)
 {
-	int ret;
+	/*
+	 * The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EXPERT)
+	 * but the module doesn't depend on any fb console symbols.  At least
+	 * attempt to load fbcon to avoid leaving the system without a usable
+	 * console.
+	 */
+	if (IS_ENABLED(CONFIG_DRM_FBDEV_EMULATION) &&
+	    IS_MODULE(CONFIG_FRAMEBUFFER_CONSOLE) &&
+	    !IS_ENABLED(CONFIG_EXPERT))
+		request_module_nowait("fbcon");
 
-	/* Call init functions from specific kms helpers here */
+	return drm_dp_aux_dev_init();
-	ret = drm_fb_helper_modinit();
-	if (ret < 0)
-		goto out;
-
-	ret = drm_dp_aux_dev_init();
-	if (ret < 0)
-		goto out;
-
-out:
-	return ret;
 }
 
 static void __exit drm_kms_helper_exit(void)

include/asm-generic/vmlinux.lds.h

@@ -497,27 +497,6 @@
 		__stop___ksymtab_gpl = .;				\
 	}								\
 									\
-	/* Kernel symbol table: Normal unused symbols */		\
-	__ksymtab_unused  : AT(ADDR(__ksymtab_unused) - LOAD_OFFSET) {	\
-		__start___ksymtab_unused = .;				\
-		KEEP(*(SORT(___ksymtab_unused+*)))			\
-		__stop___ksymtab_unused = .;				\
-	}								\
-									\
-	/* Kernel symbol table: GPL-only unused symbols */		\
-	__ksymtab_unused_gpl : AT(ADDR(__ksymtab_unused_gpl) - LOAD_OFFSET) { \
-		__start___ksymtab_unused_gpl = .;			\
-		KEEP(*(SORT(___ksymtab_unused_gpl+*)))			\
-		__stop___ksymtab_unused_gpl = .;			\
-	}								\
-									\
-	/* Kernel symbol table: GPL-future-only symbols */		\
-	__ksymtab_gpl_future : AT(ADDR(__ksymtab_gpl_future) - LOAD_OFFSET) { \
-		__start___ksymtab_gpl_future = .;			\
-		KEEP(*(SORT(___ksymtab_gpl_future+*)))			\
-		__stop___ksymtab_gpl_future = .;			\
-	}								\
-									\
 	/* Kernel symbol table: Normal symbols */			\
 	__kcrctab         : AT(ADDR(__kcrctab) - LOAD_OFFSET) {		\
 		__start___kcrctab = .;					\
@@ -532,27 +511,6 @@
 		__stop___kcrctab_gpl = .;				\
 	}								\
 									\
-	/* Kernel symbol table: Normal unused symbols */		\
-	__kcrctab_unused  : AT(ADDR(__kcrctab_unused) - LOAD_OFFSET) {	\
-		__start___kcrctab_unused = .;				\
-		KEEP(*(SORT(___kcrctab_unused+*)))			\
-		__stop___kcrctab_unused = .;				\
-	}								\
-									\
-	/* Kernel symbol table: GPL-only unused symbols */		\
-	__kcrctab_unused_gpl : AT(ADDR(__kcrctab_unused_gpl) - LOAD_OFFSET) { \
-		__start___kcrctab_unused_gpl = .;			\
-		KEEP(*(SORT(___kcrctab_unused_gpl+*)))			\
-		__stop___kcrctab_unused_gpl = .;			\
-	}								\
-									\
-	/* Kernel symbol table: GPL-future-only symbols */		\
-	__kcrctab_gpl_future : AT(ADDR(__kcrctab_gpl_future) - LOAD_OFFSET) { \
-		__start___kcrctab_gpl_future = .;			\
-		KEEP(*(SORT(___kcrctab_gpl_future+*)))			\
-		__stop___kcrctab_gpl_future = .;			\
-	}								\
-									\
 	/* Kernel symbol table: strings */				\
         __ksymtab_strings : AT(ADDR(__ksymtab_strings) - LOAD_OFFSET) {	\
 		*(__ksymtab_strings)					\

include/linux/export.h

@@ -157,18 +157,9 @@ struct kernel_symbol {
 
 #define EXPORT_SYMBOL(sym)		_EXPORT_SYMBOL(sym, "")
 #define EXPORT_SYMBOL_GPL(sym)		_EXPORT_SYMBOL(sym, "_gpl")
-#define EXPORT_SYMBOL_GPL_FUTURE(sym)	_EXPORT_SYMBOL(sym, "_gpl_future")
 #define EXPORT_SYMBOL_NS(sym, ns)	__EXPORT_SYMBOL(sym, "", #ns)
 #define EXPORT_SYMBOL_NS_GPL(sym, ns)	__EXPORT_SYMBOL(sym, "_gpl", #ns)
 
-#ifdef CONFIG_UNUSED_SYMBOLS
-#define EXPORT_UNUSED_SYMBOL(sym)	_EXPORT_SYMBOL(sym, "_unused")
-#define EXPORT_UNUSED_SYMBOL_GPL(sym)	_EXPORT_SYMBOL(sym, "_unused_gpl")
-#else
-#define EXPORT_UNUSED_SYMBOL(sym)
-#define EXPORT_UNUSED_SYMBOL_GPL(sym)
-#endif
-
 #endif /* !__ASSEMBLY__ */
 
 #endif /* _LINUX_EXPORT_H */

include/linux/kallsyms.h

@@ -71,15 +71,14 @@ static inline void *dereference_symbol_descriptor(void *ptr)
 	return ptr;
 }
 
-#ifdef CONFIG_KALLSYMS
-/* Lookup the address for a symbol. Returns 0 if not found. */
-unsigned long kallsyms_lookup_name(const char *name);
-
-/* Call a function on each kallsyms symbol in the core kernel */
 int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 				      unsigned long),
 			    void *data);
 
+#ifdef CONFIG_KALLSYMS
+/* Lookup the address for a symbol. Returns 0 if not found. */
+unsigned long kallsyms_lookup_name(const char *name);
+
 extern int kallsyms_lookup_size_offset(unsigned long addr,
 				  unsigned long *symbolsize,
 				  unsigned long *offset);
@@ -108,14 +107,6 @@ static inline unsigned long kallsyms_lookup_name(const char *name)
 	return 0;
 }
 
-static inline int kallsyms_on_each_symbol(int (*fn)(void *, const char *,
-						    struct module *,
-						    unsigned long),
-					  void *data)
-{
-	return 0;
-}
-
 static inline int kallsyms_lookup_size_offset(unsigned long addr,
 					      unsigned long *symbolsize,
 					      unsigned long *offset)

include/linux/module.h

@@ -392,18 +392,6 @@ struct module {
 	const s32 *gpl_crcs;
 	bool using_gplonly_symbols;
 
-#ifdef CONFIG_UNUSED_SYMBOLS
-	/* unused exported symbols. */
-	const struct kernel_symbol *unused_syms;
-	const s32 *unused_crcs;
-	unsigned int num_unused_syms;
-
-	/* GPL-only, unused exported symbols. */
-	unsigned int num_unused_gpl_syms;
-	const struct kernel_symbol *unused_gpl_syms;
-	const s32 *unused_gpl_crcs;
-#endif
-
 #ifdef CONFIG_MODULE_SIG
 	/* Signature was verified. */
 	bool sig_ok;
@@ -411,11 +399,6 @@ struct module {
 
 	bool async_probe_requested;
 
-	/* symbols that will be GPL-only in the near future. */
-	const struct kernel_symbol *gpl_future_syms;
-	const s32 *gpl_future_crcs;
-	unsigned int num_gpl_future_syms;
-
 	/* Exception table */
 	unsigned int num_exentries;
 	struct exception_table_entry *extable;
@@ -550,8 +533,6 @@ static inline unsigned long kallsyms_symbol_value(const Elf_Sym *sym)
 }
 #endif
 
-extern struct mutex module_mutex;
-
 /* FIXME: It'd be nice to isolate modules during init, too, so they
    aren't used before they (may) fail.  But presently too much code
    (IDE & SCSI) require entry into the module during init.*/
@@ -586,20 +567,9 @@ static inline bool within_module(unsigned long addr, const struct module *mod)
 	return within_module_init(addr, mod) || within_module_core(addr, mod);
 }
 
-/* Search for module by name: must hold module_mutex. */
+/* Search for module by name: must be in a RCU-sched critical section. */
 struct module *find_module(const char *name);
 
-struct symsearch {
-	const struct kernel_symbol *start, *stop;
-	const s32 *crcs;
-	enum mod_license {
-		NOT_GPL_ONLY,
-		GPL_ONLY,
-		WILL_BE_GPL_ONLY,
-	} license;
-	bool unused;
-};
-
 /* Returns 0 and fills in value, defined and namebuf, or -ERANGE if
    symnum out of range. */
 int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
@@ -608,10 +578,6 @@ int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
 /* Look for this name: can be of form module:name. */
 unsigned long module_kallsyms_lookup_name(const char *name);
 
-int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
-					     struct module *, unsigned long),
-				   void *data);
-
 extern void __noreturn __module_put_and_exit(struct module *mod,
 			long code);
 #define module_put_and_exit(code) __module_put_and_exit(THIS_MODULE, code)
@@ -795,14 +761,6 @@ static inline unsigned long module_kallsyms_lookup_name(const char *name)
 	return 0;
 }
 
-static inline int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
-							   struct module *,
-							   unsigned long),
-						 void *data)
-{
-	return 0;
-}
-
 static inline int register_module_notifier(struct notifier_block *nb)
 {
 	/* no events will happen anyway, so this can always succeed */
@@ -891,4 +849,8 @@ static inline bool module_sig_ok(struct module *module)
 }
 #endif	/* CONFIG_MODULE_SIG */
 
+int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
+					     struct module *, unsigned long),
+				   void *data);
+
 #endif /* _LINUX_MODULE_H */

init/Kconfig

@@ -2272,25 +2272,8 @@ config MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
 
 	  If unsure, say N.
 
-config UNUSED_SYMBOLS
-	bool "Enable unused/obsolete exported symbols"
-	default y if X86
-	help
-	  Unused but exported symbols make the kernel needlessly bigger.  For
-	  that reason most of these unused exports will soon be removed.  This
-	  option is provided temporarily to provide a transition period in case
-	  some external kernel module needs one of these symbols anyway. If you
-	  encounter such a case in your module, consider if you are actually
-	  using the right API.  (rationale: since nobody in the kernel is using
-	  this in a module, there is a pretty good chance it's actually the
-	  wrong interface to use).  If you really need the symbol, please send a
-	  mail to the linux kernel mailing list mentioning the symbol and why
-	  you really need it, and what the merge plan to the mainline kernel for
-	  your module is.
-
 config TRIM_UNUSED_KSYMS
 	bool "Trim unused exported kernel symbols"
-	depends on !UNUSED_SYMBOLS
 	help
 	  The kernel and some modules make many symbols available for
 	  other modules to use via EXPORT_SYMBOL() and variants. Depending

kernel/kallsyms.c

@@ -177,6 +177,11 @@ unsigned long kallsyms_lookup_name(const char *name)
 	return module_kallsyms_lookup_name(name);
 }
 
+#ifdef CONFIG_LIVEPATCH
+/*
+ * Iterate over all symbols in vmlinux.  For symbols from modules use
+ * module_kallsyms_on_each_symbol instead.
+ */
 int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 				      unsigned long),
 			    void *data)
@@ -192,8 +197,9 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
 		if (ret != 0)
 			return ret;
 	}
-	return module_kallsyms_on_each_symbol(fn, data);
+	return 0;
 }
+#endif /* CONFIG_LIVEPATCH */
 
 static unsigned long get_symbol_pos(unsigned long addr,
 				    unsigned long *symbolsize,

kernel/livepatch/core.c

@@ -19,6 +19,7 @@
 #include <linux/moduleloader.h>
 #include <linux/completion.h>
 #include <linux/memory.h>
+#include <linux/rcupdate.h>
 #include <asm/cacheflush.h>
 #include "core.h"
 #include "patch.h"
@@ -57,7 +58,7 @@ static void klp_find_object_module(struct klp_object *obj)
 	if (!klp_is_module(obj))
 		return;
 
-	mutex_lock(&module_mutex);
+	rcu_read_lock_sched();
 	/*
 	 * We do not want to block removal of patched modules and therefore
 	 * we do not take a reference here. The patches are removed by
@@ -74,7 +75,7 @@ static void klp_find_object_module(struct klp_object *obj)
 	if (mod && mod->klp_alive)
 		obj->mod = mod;
 
-	mutex_unlock(&module_mutex);
+	rcu_read_unlock_sched();
 }
 
 static bool klp_initialized(void)
@@ -163,12 +164,10 @@ static int klp_find_object_symbol(const char *objname, const char *name,
 		.pos = sympos,
 	};
 
-	mutex_lock(&module_mutex);
 	if (objname)
 		module_kallsyms_on_each_symbol(klp_find_callback, &args);
 	else
 		kallsyms_on_each_symbol(klp_find_callback, &args);
-	mutex_unlock(&module_mutex);
 
 	/*
 	 * Ensure an address was found. If sympos is 0, ensure symbol is unique;

kernel/module.c

@@ -87,8 +87,7 @@
  * 3) module_addr_min/module_addr_max.
  * (delete and add uses RCU list operations).
  */
-DEFINE_MUTEX(module_mutex);
+static DEFINE_MUTEX(module_mutex);
-EXPORT_SYMBOL_GPL(module_mutex);
 static LIST_HEAD(modules);
 
 /* Work queue for freeing init sections in success case */
@@ -256,11 +255,6 @@ static void mod_update_bounds(struct module *mod)
 struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
 #endif /* CONFIG_KGDB_KDB */
 
-static void module_assert_mutex(void)
-{
-	lockdep_assert_held(&module_mutex);
-}
-
 static void module_assert_mutex_or_preempt(void)
 {
 #ifdef CONFIG_LOCKDEP
@@ -414,19 +408,8 @@ extern const struct kernel_symbol __start___ksymtab[];
 extern const struct kernel_symbol __stop___ksymtab[];
 extern const struct kernel_symbol __start___ksymtab_gpl[];
 extern const struct kernel_symbol __stop___ksymtab_gpl[];
-extern const struct kernel_symbol __start___ksymtab_gpl_future[];
-extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
 extern const s32 __start___kcrctab[];
 extern const s32 __start___kcrctab_gpl[];
-extern const s32 __start___kcrctab_gpl_future[];
-#ifdef CONFIG_UNUSED_SYMBOLS
-extern const struct kernel_symbol __start___ksymtab_unused[];
-extern const struct kernel_symbol __stop___ksymtab_unused[];
-extern const struct kernel_symbol __start___ksymtab_unused_gpl[];
-extern const struct kernel_symbol __stop___ksymtab_unused_gpl[];
-extern const s32 __start___kcrctab_unused[];
-extern const s32 __start___kcrctab_unused_gpl[];
-#endif
 
 #ifndef CONFIG_MODVERSIONS
 #define symversion(base, idx) NULL
@@ -434,87 +417,14 @@ extern const s32 __start___kcrctab_unused_gpl[];
 #define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
 #endif
 
-static bool each_symbol_in_section(const struct symsearch *arr,
+struct symsearch {
-				   unsigned int arrsize,
+	const struct kernel_symbol *start, *stop;
-				   struct module *owner,
+	const s32 *crcs;
-				   bool (*fn)(const struct symsearch *syms,
+	enum mod_license {
-					      struct module *owner,
+		NOT_GPL_ONLY,
-					      void *data),
+		GPL_ONLY,
-				   void *data)
+	} license;
-{
+};
-	unsigned int j;
-
-	for (j = 0; j < arrsize; j++) {
-		if (fn(&arr[j], owner, data))
-			return true;
-	}
-
-	return false;
-}
-
-/* Returns true as soon as fn returns true, otherwise false. */
-static bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
-				    struct module *owner,
-				    void *data),
-			 void *data)
-{
-	struct module *mod;
-	static const struct symsearch arr[] = {
-		{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
-		  NOT_GPL_ONLY, false },
-		{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
-		  __start___kcrctab_gpl,
-		  GPL_ONLY, false },
-		{ __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
-		  __start___kcrctab_gpl_future,
-		  WILL_BE_GPL_ONLY, false },
-#ifdef CONFIG_UNUSED_SYMBOLS
-		{ __start___ksymtab_unused, __stop___ksymtab_unused,
-		  __start___kcrctab_unused,
-		  NOT_GPL_ONLY, true },
-		{ __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
-		  __start___kcrctab_unused_gpl,
-		  GPL_ONLY, true },
-#endif
-	};
-
-	module_assert_mutex_or_preempt();
-
-	if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
-		return true;
-
-	list_for_each_entry_rcu(mod, &modules, list,
-				lockdep_is_held(&module_mutex)) {
-		struct symsearch arr[] = {
-			{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
-			  NOT_GPL_ONLY, false },
-			{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
-			  mod->gpl_crcs,
-			  GPL_ONLY, false },
-			{ mod->gpl_future_syms,
-			  mod->gpl_future_syms + mod->num_gpl_future_syms,
-			  mod->gpl_future_crcs,
-			  WILL_BE_GPL_ONLY, false },
-#ifdef CONFIG_UNUSED_SYMBOLS
-			{ mod->unused_syms,
-			  mod->unused_syms + mod->num_unused_syms,
-			  mod->unused_crcs,
-			  NOT_GPL_ONLY, true },
-			{ mod->unused_gpl_syms,
-			  mod->unused_gpl_syms + mod->num_unused_gpl_syms,
-			  mod->unused_gpl_crcs,
-			  GPL_ONLY, true },
-#endif
-		};
-
-		if (mod->state == MODULE_STATE_UNFORMED)
-			continue;
-
-		if (each_symbol_in_section(arr, ARRAY_SIZE(arr), mod, fn, data))
-			return true;
-	}
-	return false;
-}
 
 struct find_symbol_arg {
 	/* Input */
@@ -535,28 +445,8 @@ static bool check_exported_symbol(const struct symsearch *syms,
 {
 	struct find_symbol_arg *fsa = data;
 
-	if (!fsa->gplok) {
+	if (!fsa->gplok && syms->license == GPL_ONLY)
-		if (syms->license == GPL_ONLY)
+		return false;
-			return false;
-		if (syms->license == WILL_BE_GPL_ONLY && fsa->warn) {
-			pr_warn("Symbol %s is being used by a non-GPL module, "
-				"which will not be allowed in the future\n",
-				fsa->name);
-		}
-	}
-
-#ifdef CONFIG_UNUSED_SYMBOLS
-	if (syms->unused && fsa->warn) {
-		pr_warn("Symbol %s is marked as UNUSED, however this module is "
-			"using it.\n", fsa->name);
-		pr_warn("This symbol will go away in the future.\n");
-		pr_warn("Please evaluate if this is the right api to use and "
-			"if it really is, submit a report to the linux kernel "
-			"mailing list together with submitting your code for "
-			"inclusion.\n");
-	}
-#endif
-
 	fsa->owner = owner;
 	fsa->crc = symversion(syms->crcs, symnum);
 	fsa->sym = &syms->start[symnum];
@@ -619,31 +509,44 @@ static bool find_exported_symbol_in_section(const struct symsearch *syms,
  * Find an exported symbol and return it, along with, (optional) crc and
  * (optional) module which owns it.  Needs preempt disabled or module_mutex.
  */
-static const struct kernel_symbol *find_symbol(const char *name,
+static bool find_symbol(struct find_symbol_arg *fsa)
-					struct module **owner,
-					const s32 **crc,
-					enum mod_license *license,
-					bool gplok,
-					bool warn)
 {
-	struct find_symbol_arg fsa;
+	static const struct symsearch arr[] = {
+		{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
+		  NOT_GPL_ONLY },
+		{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
+		  __start___kcrctab_gpl,
+		  GPL_ONLY },
+	};
+	struct module *mod;
+	unsigned int i;
 
-	fsa.name = name;
+	module_assert_mutex_or_preempt();
-	fsa.gplok = gplok;
-	fsa.warn = warn;
 
-	if (each_symbol_section(find_exported_symbol_in_section, &fsa)) {
+	for (i = 0; i < ARRAY_SIZE(arr); i++)
-		if (owner)
+		if (find_exported_symbol_in_section(&arr[i], NULL, fsa))
-			*owner = fsa.owner;
+			return true;
-		if (crc)
+
-			*crc = fsa.crc;
+	list_for_each_entry_rcu(mod, &modules, list,
-		if (license)
+				lockdep_is_held(&module_mutex)) {
-			*license = fsa.license;
+		struct symsearch arr[] = {
-		return fsa.sym;
+			{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
+			  NOT_GPL_ONLY },
+			{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
+			  mod->gpl_crcs,
+			  GPL_ONLY },
+		};
+
+		if (mod->state == MODULE_STATE_UNFORMED)
+			continue;
+
+		for (i = 0; i < ARRAY_SIZE(arr); i++)
+			if (find_exported_symbol_in_section(&arr[i], mod, fsa))
+				return true;
 	}
 
-	pr_debug("Failed to find symbol %s\n", name);
+	pr_debug("Failed to find symbol %s\n", fsa->name);
-	return NULL;
+	return false;
 }
 
 /*
@@ -669,10 +572,8 @@ static struct module *find_module_all(const char *name, size_t len,
 
 struct module *find_module(const char *name)
 {
-	module_assert_mutex();
 	return find_module_all(name, strlen(name), false);
 }
-EXPORT_SYMBOL_GPL(find_module);
 
 #ifdef CONFIG_SMP
 
@@ -1107,12 +1008,15 @@ static inline void print_unload_info(struct seq_file *m, struct module *mod)
 
 void __symbol_put(const char *symbol)
 {
-	struct module *owner;
+	struct find_symbol_arg fsa = {
+		.name	= symbol,
+		.gplok	= true,
+	};
 
 	preempt_disable();
-	if (!find_symbol(symbol, &owner, NULL, NULL, true, false))
+	if (!find_symbol(&fsa))
 		BUG();
-	module_put(owner);
+	module_put(fsa.owner);
 	preempt_enable();
 }
 EXPORT_SYMBOL(__symbol_put);
@@ -1381,19 +1285,22 @@ bad_version:
 static inline int check_modstruct_version(const struct load_info *info,
 					  struct module *mod)
 {
-	const s32 *crc;
+	struct find_symbol_arg fsa = {
+		.name	= "module_layout",
+		.gplok	= true,
+	};
 
 	/*
 	 * Since this should be found in kernel (which can't be removed), no
 	 * locking is necessary -- use preempt_disable() to placate lockdep.
 	 */
 	preempt_disable();
-	if (!find_symbol("module_layout", NULL, &crc, NULL, true, false)) {
+	if (!find_symbol(&fsa)) {
 		preempt_enable();
 		BUG();
 	}
 	preempt_enable();
-	return check_version(info, "module_layout", mod, crc);
+	return check_version(info, "module_layout", mod, fsa.crc);
 }
 
 /* First part is kernel version, which we ignore if module has crcs. */
@@ -1487,10 +1394,11 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
 						  const char *name,
 						  char ownername[])
 {
-	struct module *owner;
+	struct find_symbol_arg fsa = {
-	const struct kernel_symbol *sym;
+		.name	= name,
-	const s32 *crc;
+		.gplok	= !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)),
-	enum mod_license license;
+		.warn	= true,
+	};
 	int err;
 
 	/*
@@ -1500,42 +1408,40 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
 	 */
 	sched_annotate_sleep();
 	mutex_lock(&module_mutex);
-	sym = find_symbol(name, &owner, &crc, &license,
+	if (!find_symbol(&fsa))
-			  !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true);
-	if (!sym)
 		goto unlock;
 
-	if (license == GPL_ONLY)
+	if (fsa.license == GPL_ONLY)
 		mod->using_gplonly_symbols = true;
 
-	if (!inherit_taint(mod, owner)) {
+	if (!inherit_taint(mod, fsa.owner)) {
-		sym = NULL;
+		fsa.sym = NULL;
 		goto getname;
 	}
 
-	if (!check_version(info, name, mod, crc)) {
+	if (!check_version(info, name, mod, fsa.crc)) {
-		sym = ERR_PTR(-EINVAL);
+		fsa.sym = ERR_PTR(-EINVAL);
 		goto getname;
 	}
 
-	err = verify_namespace_is_imported(info, sym, mod);
+	err = verify_namespace_is_imported(info, fsa.sym, mod);
 	if (err) {
-		sym = ERR_PTR(err);
+		fsa.sym = ERR_PTR(err);
 		goto getname;
 	}
 
-	err = ref_module(mod, owner);
+	err = ref_module(mod, fsa.owner);
 	if (err) {
-		sym = ERR_PTR(err);
+		fsa.sym = ERR_PTR(err);
 		goto getname;
 	}
 
 getname:
 	/* We must make copy under the lock if we failed to get ref. */
-	strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
+	strncpy(ownername, module_name(fsa.owner), MODULE_NAME_LEN);
 unlock:
 	mutex_unlock(&module_mutex);
-	return sym;
+	return fsa.sym;
 }
 
 static const struct kernel_symbol *
@@ -2296,16 +2202,19 @@ static void free_module(struct module *mod)
 
 void *__symbol_get(const char *symbol)
 {
-	struct module *owner;
+	struct find_symbol_arg fsa = {
-	const struct kernel_symbol *sym;
+		.name	= symbol,
+		.gplok	= true,
+		.warn	= true,
+	};
 
 	preempt_disable();
-	sym = find_symbol(symbol, &owner, NULL, NULL, true, true);
+	if (!find_symbol(&fsa) || strong_try_module_get(fsa.owner)) {
-	if (sym && strong_try_module_get(owner))
+		preempt_enable();
-		sym = NULL;
+		return NULL;
+	}
 	preempt_enable();
-
+	return (void *)kernel_symbol_value(fsa.sym);
-	return sym ? (void *)kernel_symbol_value(sym) : NULL;
 }
 EXPORT_SYMBOL_GPL(__symbol_get);
 
@@ -2318,7 +2227,6 @@ EXPORT_SYMBOL_GPL(__symbol_get);
 static int verify_exported_symbols(struct module *mod)
 {
 	unsigned int i;
-	struct module *owner;
 	const struct kernel_symbol *s;
 	struct {
 		const struct kernel_symbol *sym;
@@ -2326,21 +2234,19 @@ static int verify_exported_symbols(struct module *mod)
 	} arr[] = {
 		{ mod->syms, mod->num_syms },
 		{ mod->gpl_syms, mod->num_gpl_syms },
-		{ mod->gpl_future_syms, mod->num_gpl_future_syms },
-#ifdef CONFIG_UNUSED_SYMBOLS
-		{ mod->unused_syms, mod->num_unused_syms },
-		{ mod->unused_gpl_syms, mod->num_unused_gpl_syms },
-#endif
 	};
 
 	for (i = 0; i < ARRAY_SIZE(arr); i++) {
 		for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
-			if (find_symbol(kernel_symbol_name(s), &owner, NULL,
+			struct find_symbol_arg fsa = {
-					NULL, true, false)) {
+				.name	= kernel_symbol_name(s),
+				.gplok	= true,
+			};
+			if (find_symbol(&fsa)) {
 				pr_err("%s: exports duplicate symbol %s"
 				       " (owned by %s)\n",
 				       mod->name, kernel_symbol_name(s),
-				       module_name(owner));
+				       module_name(fsa.owner));
 				return -ENOEXEC;
 			}
 		}
@@ -2348,6 +2254,21 @@ static int verify_exported_symbols(struct module *mod)
 	return 0;
 }
 
+static bool ignore_undef_symbol(Elf_Half emachine, const char *name)
+{
+	/*
+	 * On x86, PIC code and Clang non-PIC code may have call foo@PLT. GNU as
+	 * before 2.37 produces an unreferenced _GLOBAL_OFFSET_TABLE_ on x86-64.
+	 * i386 has a similar problem but may not deserve a fix.
+	 *
+	 * If we ever have to ignore many symbols, consider refactoring the code to
+	 * only warn if referenced by a relocation.
+	 */
+	if (emachine == EM_386 || emachine == EM_X86_64)
+		return !strcmp(name, "_GLOBAL_OFFSET_TABLE_");
+	return false;
+}
+
 /* Change all symbols so that st_value encodes the pointer directly. */
 static int simplify_symbols(struct module *mod, const struct load_info *info)
 {
@@ -2395,8 +2316,10 @@ static int simplify_symbols(struct module *mod, const struct load_info *info)
 				break;
 			}
 
-			/* Ok if weak.  */
+			/* Ok if weak or ignored.  */
-			if (!ksym && ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
+			if (!ksym &&
+			    (ELF_ST_BIND(sym[i].st_info) == STB_WEAK ||
+			     ignore_undef_symbol(info->hdr->e_machine, name)))
 				break;
 
 			ret = PTR_ERR(ksym) ?: -ENOENT;
@@ -2964,7 +2887,7 @@ static int module_sig_check(struct load_info *info, int flags)
 	}
 
 	if (is_module_sig_enforced()) {
-		pr_notice("%s: loading of %s is rejected\n", info->name, reason);
+		pr_notice("Loading of %s is rejected\n", reason);
 		return -EKEYREJECTED;
 	}
 
@@ -2977,9 +2900,33 @@ static int module_sig_check(struct load_info *info, int flags)
 }
 #endif /* !CONFIG_MODULE_SIG */
 
-/* Sanity checks against invalid binaries, wrong arch, weird elf version. */
+static int validate_section_offset(struct load_info *info, Elf_Shdr *shdr)
-static int elf_header_check(struct load_info *info)
 {
+	unsigned long secend;
+
+	/*
+	 * Check for both overflow and offset/size being
+	 * too large.
+	 */
+	secend = shdr->sh_offset + shdr->sh_size;
+	if (secend < shdr->sh_offset || secend > info->len)
+		return -ENOEXEC;
+
+	return 0;
+}
+
+/*
+ * Sanity checks against invalid binaries, wrong arch, weird elf version.
+ *
+ * Also do basic validity checks against section offsets and sizes, the
+ * section name string table, and the indices used for it (sh_name).
+ */
+static int elf_validity_check(struct load_info *info)
+{
+	unsigned int i;
+	Elf_Shdr *shdr, *strhdr;
+	int err;
+
 	if (info->len < sizeof(*(info->hdr)))
 		return -ENOEXEC;
 
@@ -2989,11 +2936,78 @@ static int elf_header_check(struct load_info *info)
 	    || info->hdr->e_shentsize != sizeof(Elf_Shdr))
 		return -ENOEXEC;
 
+	/*
+	 * e_shnum is 16 bits, and sizeof(Elf_Shdr) is
+	 * known and small. So e_shnum * sizeof(Elf_Shdr)
+	 * will not overflow unsigned long on any platform.
+	 */
 	if (info->hdr->e_shoff >= info->len
 	    || (info->hdr->e_shnum * sizeof(Elf_Shdr) >
 		info->len - info->hdr->e_shoff))
 		return -ENOEXEC;
 
+	info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;
+
+	/*
+	 * Verify if the section name table index is valid.
+	 */
+	if (info->hdr->e_shstrndx == SHN_UNDEF
+	    || info->hdr->e_shstrndx >= info->hdr->e_shnum)
+		return -ENOEXEC;
+
+	strhdr = &info->sechdrs[info->hdr->e_shstrndx];
+	err = validate_section_offset(info, strhdr);
+	if (err < 0)
+		return err;
+
+	/*
+	 * The section name table must be NUL-terminated, as required
+	 * by the spec. This makes strcmp and pr_* calls that access
+	 * strings in the section safe.
+	 */
+	info->secstrings = (void *)info->hdr + strhdr->sh_offset;
+	if (info->secstrings[strhdr->sh_size - 1] != '\0')
+		return -ENOEXEC;
+
+	/*
+	 * The code assumes that section 0 has a length of zero and
+	 * an addr of zero, so check for it.
+	 */
+	if (info->sechdrs[0].sh_type != SHT_NULL
+	    || info->sechdrs[0].sh_size != 0
+	    || info->sechdrs[0].sh_addr != 0)
+		return -ENOEXEC;
+
+	for (i = 1; i < info->hdr->e_shnum; i++) {
+		shdr = &info->sechdrs[i];
+		switch (shdr->sh_type) {
+		case SHT_NULL:
+		case SHT_NOBITS:
+			continue;
+		case SHT_SYMTAB:
+			if (shdr->sh_link == SHN_UNDEF
+			    || shdr->sh_link >= info->hdr->e_shnum)
+				return -ENOEXEC;
+			fallthrough;
+		default:
+			err = validate_section_offset(info, shdr);
+			if (err < 0) {
+				pr_err("Invalid ELF section in module (section %u type %u)\n",
+					i, shdr->sh_type);
+				return err;
+			}
+
+			if (shdr->sh_flags & SHF_ALLOC) {
+				if (shdr->sh_name >= strhdr->sh_size) {
+					pr_err("Invalid ELF section name in module (section %u type %u)\n",
+					       i, shdr->sh_type);
+					return -ENOEXEC;
+				}
+			}
+			break;
+		}
+	}
+
 	return 0;
 }
 
@@ -3095,11 +3109,6 @@ static int rewrite_section_headers(struct load_info *info, int flags)
 
 	for (i = 1; i < info->hdr->e_shnum; i++) {
 		Elf_Shdr *shdr = &info->sechdrs[i];
-		if (shdr->sh_type != SHT_NOBITS
-		    && info->len < shdr->sh_offset + shdr->sh_size) {
-			pr_err("Module len %lu truncated\n", info->len);
-			return -ENOEXEC;
-		}
 
 		/*
 		 * Mark all sections sh_addr with their address in the
@@ -3133,11 +3142,6 @@ static int setup_load_info(struct load_info *info, int flags)
 {
 	unsigned int i;
 
-	/* Set up the convenience variables */
-	info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;
-	info->secstrings = (void *)info->hdr
-		+ info->sechdrs[info->hdr->e_shstrndx].sh_offset;
-
 	/* Try to find a name early so we can log errors with a module name */
 	info->index.info = find_sec(info, ".modinfo");
 	if (info->index.info)
@@ -3241,22 +3245,7 @@ static int find_module_sections(struct module *mod, struct load_info *info)
 				     sizeof(*mod->gpl_syms),
 				     &mod->num_gpl_syms);
 	mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
-	mod->gpl_future_syms = section_objs(info,
-					    "__ksymtab_gpl_future",
-					    sizeof(*mod->gpl_future_syms),
-					    &mod->num_gpl_future_syms);
-	mod->gpl_future_crcs = section_addr(info, "__kcrctab_gpl_future");
 
-#ifdef CONFIG_UNUSED_SYMBOLS
-	mod->unused_syms = section_objs(info, "__ksymtab_unused",
-					sizeof(*mod->unused_syms),
-					&mod->num_unused_syms);
-	mod->unused_crcs = section_addr(info, "__kcrctab_unused");
-	mod->unused_gpl_syms = section_objs(info, "__ksymtab_unused_gpl",
-					    sizeof(*mod->unused_gpl_syms),
-					    &mod->num_unused_gpl_syms);
-	mod->unused_gpl_crcs = section_addr(info, "__kcrctab_unused_gpl");
-#endif
 #ifdef CONFIG_CONSTRUCTORS
 	mod->ctors = section_objs(info, ".ctors",
 				  sizeof(*mod->ctors), &mod->num_ctors);
@@ -3437,14 +3426,8 @@ static int check_module_license_and_versions(struct module *mod)
 		pr_warn("%s: module license taints kernel.\n", mod->name);
 
 #ifdef CONFIG_MODVERSIONS
-	if ((mod->num_syms && !mod->crcs)
+	if ((mod->num_syms && !mod->crcs) ||
-	    || (mod->num_gpl_syms && !mod->gpl_crcs)
+	    (mod->num_gpl_syms && !mod->gpl_crcs)) {
-	    || (mod->num_gpl_future_syms && !mod->gpl_future_crcs)
-#ifdef CONFIG_UNUSED_SYMBOLS
-	    || (mod->num_unused_syms && !mod->unused_crcs)
-	    || (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
-#endif
-		) {
 		return try_to_force_load(mod,
 					 "no versions for exported symbols");
 	}
@@ -3894,26 +3877,50 @@ static int load_module(struct load_info *info, const char __user *uargs,
 	long err = 0;
 	char *after_dashes;
 
-	err = elf_header_check(info);
+	/*
+	 * Do the signature check (if any) first. All that
+	 * the signature check needs is info->len, it does
+	 * not need any of the section info. That can be
+	 * set up later. This will minimize the chances
+	 * of a corrupt module causing problems before
+	 * we even get to the signature check.
+	 *
+	 * The check will also adjust info->len by stripping
+	 * off the sig length at the end of the module, making
+	 * checks against info->len more correct.
+	 */
+	err = module_sig_check(info, flags);
+	if (err)
+		goto free_copy;
+
+	/*
+	 * Do basic sanity checks against the ELF header and
+	 * sections.
+	 */
+	err = elf_validity_check(info);
 	if (err) {
-		pr_err("Module has invalid ELF header\n");
+		pr_err("Module has invalid ELF structures\n");
 		goto free_copy;
 	}
 
+	/*
+	 * Everything checks out, so set up the section info
+	 * in the info structure.
+	 */
 	err = setup_load_info(info, flags);
 	if (err)
 		goto free_copy;
 
+	/*
+	 * Now that we know we have the correct module name, check
+	 * if it's blacklisted.
+	 */
 	if (blacklisted(info->name)) {
 		err = -EPERM;
 		pr_err("Module %s is blacklisted\n", info->name);
 		goto free_copy;
 	}
 
-	err = module_sig_check(info, flags);
-	if (err)
-		goto free_copy;
-
 	err = rewrite_section_headers(info, flags);
 	if (err)
 		goto free_copy;
@@ -4374,16 +4381,16 @@ unsigned long module_kallsyms_lookup_name(const char *name)
 	return ret;
 }
 
+#ifdef CONFIG_LIVEPATCH
 int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 					     struct module *, unsigned long),
 				   void *data)
 {
 	struct module *mod;
 	unsigned int i;
-	int ret;
+	int ret = 0;
-
-	module_assert_mutex();
 
+	mutex_lock(&module_mutex);
 	list_for_each_entry(mod, &modules, list) {
 		/* We hold module_mutex: no need for rcu_dereference_sched */
 		struct mod_kallsyms *kallsyms = mod->kallsyms;
@@ -4399,11 +4406,13 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
 			ret = fn(data, kallsyms_symbol_name(kallsyms, i),
 				 mod, kallsyms_symbol_value(sym));
 			if (ret != 0)
-				return ret;
+				break;
 		}
 	}
-	return 0;
+	mutex_unlock(&module_mutex);
+	return ret;
 }
+#endif /* CONFIG_LIVEPATCH */
 #endif /* CONFIG_KALLSYMS */
 
 /* Maximum number of characters written by module_flags() */

kernel/module_signature.c

@@ -25,7 +25,7 @@ int mod_check_sig(const struct module_signature *ms, size_t file_len,
 		return -EBADMSG;
 
 	if (ms->id_type != PKEY_ID_PKCS7) {
-		pr_err("%s: Module is not signed with expected PKCS#7 message\n",
+		pr_err("%s: not signed with expected PKCS#7 message\n",
 		       name);
 		return -ENOPKG;
 	}

kernel/module_signing.c

@@ -30,7 +30,7 @@ int mod_verify_sig(const void *mod, struct load_info *info)
 
 	memcpy(&ms, mod + (modlen - sizeof(ms)), sizeof(ms));
 
-	ret = mod_check_sig(&ms, modlen, info->name);
+	ret = mod_check_sig(&ms, modlen, "module");
 	if (ret)
 		return ret;
 

kernel/trace/trace_kprobe.c

@@ -124,9 +124,9 @@ static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
 	if (!p)
 		return true;
 	*p = '\0';
-	mutex_lock(&module_mutex);
+	rcu_read_lock_sched();
 	ret = !!find_module(tk->symbol);
-	mutex_unlock(&module_mutex);
+	rcu_read_unlock_sched();
 	*p = ':';
 
 	return ret;

lib/bug.c

@@ -91,8 +91,6 @@ void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
 	char *secstrings;
 	unsigned int i;
 
-	lockdep_assert_held(&module_mutex);
-
 	mod->bug_table = NULL;
 	mod->num_bugs = 0;
 
@@ -118,7 +116,6 @@ void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
 
 void module_bug_cleanup(struct module *mod)
 {
-	lockdep_assert_held(&module_mutex);
 	list_del_rcu(&mod->bug_list);
 }
 

scripts/checkpatch.pl

@@ -4283,8 +4283,7 @@ sub process {
 		if (defined $realline_next &&
 		    exists $lines[$realline_next - 1] &&
 		    !defined $suppress_export{$realline_next} &&
-		    ($lines[$realline_next - 1] =~ /EXPORT_SYMBOL.*\((.*)\)/ ||
+		    ($lines[$realline_next - 1] =~ /EXPORT_SYMBOL.*\((.*)\)/)) {
-		     $lines[$realline_next - 1] =~ /EXPORT_UNUSED_SYMBOL.*\((.*)\)/)) {
 			# Handle definitions which produce identifiers with
 			# a prefix:
 			#   XXX(foo);
@@ -4311,8 +4310,7 @@ sub process {
 		}
 		if (!defined $suppress_export{$linenr} &&
 		    $prevline =~ /^.\s*$/ &&
-		    ($line =~ /EXPORT_SYMBOL.*\((.*)\)/ ||
+		    ($line =~ /EXPORT_SYMBOL.*\((.*)\)/)) {
-		     $line =~ /EXPORT_UNUSED_SYMBOL.*\((.*)\)/)) {
 #print "FOO B <$lines[$linenr - 1]>\n";
 			$suppress_export{$linenr} = 2;
 		}

scripts/mod/modpost.c

@@ -42,8 +42,9 @@ static int allow_missing_ns_imports;
 static bool error_occurred;
 
 enum export {
-	export_plain,      export_unused,     export_gpl,
+	export_plain,
-	export_unused_gpl, export_gpl_future, export_unknown
+	export_gpl,
+	export_unknown
 };
 
 /* In kernel, this size is defined in linux/module.h;
@@ -292,10 +293,7 @@ static const struct {
 	enum export export;
 } export_list[] = {
 	{ .str = "EXPORT_SYMBOL",            .export = export_plain },
-	{ .str = "EXPORT_UNUSED_SYMBOL",     .export = export_unused },
 	{ .str = "EXPORT_SYMBOL_GPL",        .export = export_gpl },
-	{ .str = "EXPORT_UNUSED_SYMBOL_GPL", .export = export_unused_gpl },
-	{ .str = "EXPORT_SYMBOL_GPL_FUTURE", .export = export_gpl_future },
 	{ .str = "(unknown)",                .export = export_unknown },
 };
 
@@ -354,14 +352,8 @@ static enum export export_from_secname(struct elf_info *elf, unsigned int sec)
 
 	if (strstarts(secname, "___ksymtab+"))
 		return export_plain;
-	else if (strstarts(secname, "___ksymtab_unused+"))
-		return export_unused;
 	else if (strstarts(secname, "___ksymtab_gpl+"))
 		return export_gpl;
-	else if (strstarts(secname, "___ksymtab_unused_gpl+"))
-		return export_unused_gpl;
-	else if (strstarts(secname, "___ksymtab_gpl_future+"))
-		return export_gpl_future;
 	else
 		return export_unknown;
 }
@@ -370,14 +362,8 @@ static enum export export_from_sec(struct elf_info *elf, unsigned int sec)
 {
 	if (sec == elf->export_sec)
 		return export_plain;
-	else if (sec == elf->export_unused_sec)
-		return export_unused;
 	else if (sec == elf->export_gpl_sec)
 		return export_gpl;
-	else if (sec == elf->export_unused_gpl_sec)
-		return export_unused_gpl;
-	else if (sec == elf->export_gpl_future_sec)
-		return export_gpl_future;
 	else
 		return export_unknown;
 }
@@ -581,14 +567,8 @@ static int parse_elf(struct elf_info *info, const char *filename)
 			info->modinfo_len = sechdrs[i].sh_size;
 		} else if (strcmp(secname, "__ksymtab") == 0)
 			info->export_sec = i;
-		else if (strcmp(secname, "__ksymtab_unused") == 0)
-			info->export_unused_sec = i;
 		else if (strcmp(secname, "__ksymtab_gpl") == 0)
 			info->export_gpl_sec = i;
-		else if (strcmp(secname, "__ksymtab_unused_gpl") == 0)
-			info->export_unused_gpl_sec = i;
-		else if (strcmp(secname, "__ksymtab_gpl_future") == 0)
-			info->export_gpl_future_sec = i;
 
 		if (sechdrs[i].sh_type == SHT_SYMTAB) {
 			unsigned int sh_link_idx;
@@ -2146,36 +2126,13 @@ static void check_for_gpl_usage(enum export exp, const char *m, const char *s)
 		error("GPL-incompatible module %s.ko uses GPL-only symbol '%s'\n",
 		      m, s);
 		break;
-	case export_unused_gpl:
-		error("GPL-incompatible module %s.ko uses GPL-only symbol marked UNUSED '%s'\n",
-		      m, s);
-		break;
-	case export_gpl_future:
-		warn("GPL-incompatible module %s.ko uses future GPL-only symbol '%s'\n",
-		     m, s);
-		break;
 	case export_plain:
-	case export_unused:
 	case export_unknown:
 		/* ignore */
 		break;
 	}
 }
 
-static void check_for_unused(enum export exp, const char *m, const char *s)
-{
-	switch (exp) {
-	case export_unused:
-	case export_unused_gpl:
-		warn("module %s.ko uses symbol '%s' marked UNUSED\n",
-		     m, s);
-		break;
-	default:
-		/* ignore */
-		break;
-	}
-}
-
 static void check_exports(struct module *mod)
 {
 	struct symbol *s, *exp;
@@ -2206,7 +2163,6 @@ static void check_exports(struct module *mod)
 
 		if (!mod->gpl_compatible)
 			check_for_gpl_usage(exp->export, basename, exp->name);
-		check_for_unused(exp->export, basename, exp->name);
 	}
 }
 

scripts/mod/modpost.h

@@ -140,10 +140,7 @@ struct elf_info {
 	Elf_Sym      *symtab_start;
 	Elf_Sym      *symtab_stop;
 	Elf_Section  export_sec;
-	Elf_Section  export_unused_sec;
 	Elf_Section  export_gpl_sec;
-	Elf_Section  export_unused_gpl_sec;
-	Elf_Section  export_gpl_future_sec;
 	char         *strtab;
 	char	     *modinfo;
 	unsigned int modinfo_len;

scripts/module.lds.S

@@ -11,14 +11,8 @@ SECTIONS {
 
 	__ksymtab		0 : { *(SORT(___ksymtab+*)) }
 	__ksymtab_gpl		0 : { *(SORT(___ksymtab_gpl+*)) }
-	__ksymtab_unused	0 : { *(SORT(___ksymtab_unused+*)) }
-	__ksymtab_unused_gpl	0 : { *(SORT(___ksymtab_unused_gpl+*)) }
-	__ksymtab_gpl_future	0 : { *(SORT(___ksymtab_gpl_future+*)) }
 	__kcrctab		0 : { *(SORT(___kcrctab+*)) }
 	__kcrctab_gpl		0 : { *(SORT(___kcrctab_gpl+*)) }
-	__kcrctab_unused	0 : { *(SORT(___kcrctab_unused+*)) }
-	__kcrctab_unused_gpl	0 : { *(SORT(___kcrctab_unused_gpl+*)) }
-	__kcrctab_gpl_future	0 : { *(SORT(___kcrctab_gpl_future+*)) }
 
 	.init_array		0 : ALIGN(8) { *(SORT(.init_array.*)) *(.init_array) }
 

tools/include/linux/export.h

@@ -3,8 +3,5 @@
 
 #define EXPORT_SYMBOL(sym)
 #define EXPORT_SYMBOL_GPL(sym)
-#define EXPORT_SYMBOL_GPL_FUTURE(sym)
-#define EXPORT_UNUSED_SYMBOL(sym)
-#define EXPORT_UNUSED_SYMBOL_GPL(sym)
 
 #endif