From e180a6b7759a99a28cbcce3547c4c80822cb6c2a Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Tue, 31 Mar 2009 13:05:29 -0600
Subject: param: fix charp parameters set via sysfs

Impact: fix crash on reading from /sys/module/.../ieee80211_default_rc_algo

The module_param type "charp" simply sets a char * pointer in the
module to the parameter in the commandline string: this is why we keep
the (mangled) module command line around.  But when set via sysfs (as
about 11 charp parameters can be) this memory is freed on the way
out of the write().  Future reads hit random mem.

So we kstrdup instead: we have to check we're not in early commandline
parsing, and we have to note when we've used it so we can reliably
kfree the parameter when it's next overwritten, and also on module
unload.

(Thanks to Randy Dunlap for CONFIG_SYSFS=n fixes)

Reported-by: Sitsofe Wheeler <sitsofe@yahoo.com>
Diagnosed-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Frederic Weisbecker <fweisbec@gmail.com>
Tested-by: Christof Schmitt <christof.schmitt@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 include/linux/module.h      |  4 ++++
 include/linux/moduleparam.h | 10 ++++++++++
 kernel/module.c             | 14 ++++++++------
 kernel/params.c             | 26 +++++++++++++++++++++++++-
 4 files changed, 47 insertions(+), 7 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index 145a75528cc..08e5e75d612 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -248,6 +248,10 @@ struct module
 	const unsigned long *crcs;
 	unsigned int num_syms;
 
+	/* Kernel parameters. */
+	struct kernel_param *kp;
+	unsigned int num_kp;
+
 	/* GPL-only exported symbols. */
 	unsigned int num_gpl_syms;
 	const struct kernel_symbol *gpl_syms;
diff --git a/include/linux/moduleparam.h b/include/linux/moduleparam.h
index e4af3399ef4..a4f0b931846 100644
--- a/include/linux/moduleparam.h
+++ b/include/linux/moduleparam.h
@@ -138,6 +138,16 @@ extern int parse_args(const char *name,
 		      unsigned num,
 		      int (*unknown)(char *param, char *val));
 
+/* Called by module remove. */
+#ifdef CONFIG_SYSFS
+extern void destroy_params(const struct kernel_param *params, unsigned num);
+#else
+static inline void destroy_params(const struct kernel_param *params,
+				  unsigned num)
+{
+}
+#endif /* !CONFIG_SYSFS */
+
 /* All the helper functions */
 /* The macros to do compile-time type checking stolen from Jakub
    Jelinek, who IIRC came up with this idea for the 2.4 module init code. */
diff --git a/kernel/module.c b/kernel/module.c
index f77ac320d0b..b862fdb6a37 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1491,6 +1491,9 @@ static void free_module(struct module *mod)
 	/* Module unload stuff */
 	module_unload_free(mod);
 
+	/* Free any allocated parameters. */
+	destroy_params(mod->kp, mod->num_kp);
+
 	/* release any pointers to mcount in this module */
 	ftrace_release(mod->module_core, mod->core_size);
 
@@ -1898,8 +1901,7 @@ static noinline struct module *load_module(void __user *umod,
 	unsigned int symindex = 0;
 	unsigned int strindex = 0;
 	unsigned int modindex, versindex, infoindex, pcpuindex;
-	unsigned int num_kp, num_mcount;
-	struct kernel_param *kp;
+	unsigned int num_mcount;
 	struct module *mod;
 	long err = 0;
 	void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */
@@ -2144,8 +2146,8 @@ static noinline struct module *load_module(void __user *umod,
 
 	/* Now we've got everything in the final locations, we can
 	 * find optional sections. */
-	kp = section_objs(hdr, sechdrs, secstrings, "__param", sizeof(*kp),
-			  &num_kp);
+	mod->kp = section_objs(hdr, sechdrs, secstrings, "__param",
+			       sizeof(*mod->kp), &mod->num_kp);
 	mod->syms = section_objs(hdr, sechdrs, secstrings, "__ksymtab",
 				 sizeof(*mod->syms), &mod->num_syms);
 	mod->crcs = section_addr(hdr, sechdrs, secstrings, "__kcrctab");
@@ -2291,11 +2293,11 @@ static noinline struct module *load_module(void __user *umod,
 	 */
 	list_add_rcu(&mod->list, &modules);
 
-	err = parse_args(mod->name, mod->args, kp, num_kp, NULL);
+	err = parse_args(mod->name, mod->args, mod->kp, mod->num_kp, NULL);
 	if (err < 0)
 		goto unlink;
 
-	err = mod_sysfs_setup(mod, kp, num_kp);
+	err = mod_sysfs_setup(mod, mod->kp, mod->num_kp);
 	if (err < 0)
 		goto unlink;
 	add_sect_attrs(mod, hdr->e_shnum, secstrings, sechdrs);
diff --git a/kernel/params.c b/kernel/params.c
index a1e3025b19a..de273ec85bd 100644
--- a/kernel/params.c
+++ b/kernel/params.c
@@ -24,6 +24,9 @@
 #include <linux/err.h>
 #include <linux/slab.h>
 
+/* We abuse the high bits of "perm" to record whether we kmalloc'ed. */
+#define KPARAM_KMALLOCED	0x80000000
+
 #if 0
 #define DEBUGP printk
 #else
@@ -217,7 +220,19 @@ int param_set_charp(const char *val, struct kernel_param *kp)
 		return -ENOSPC;
 	}
 
-	*(char **)kp->arg = (char *)val;
+	if (kp->perm & KPARAM_KMALLOCED)
+		kfree(*(char **)kp->arg);
+
+	/* This is a hack.  We can't need to strdup in early boot, and we
+	 * don't need to; this mangled commandline is preserved. */
+	if (slab_is_available()) {
+		kp->perm |= KPARAM_KMALLOCED;
+		*(char **)kp->arg = kstrdup(val, GFP_KERNEL);
+		if (!kp->arg)
+			return -ENOMEM;
+	} else
+		*(const char **)kp->arg = val;
+
 	return 0;
 }
 
@@ -571,6 +586,15 @@ void module_param_sysfs_remove(struct module *mod)
 }
 #endif
 
+void destroy_params(const struct kernel_param *params, unsigned num)
+{
+	unsigned int i;
+
+	for (i = 0; i < num; i++)
+		if (params[i].perm & KPARAM_KMALLOCED)
+			kfree(*(char **)params[i].arg);
+}
+
 static void __init kernel_add_sysfs_param(const char *name,
 					  struct kernel_param *kparam,
 					  unsigned int name_skip)
-- 
cgit v1.2.3


From b10153fe31dde3805f8320b61ef147cebe379aee Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Am=C3=A9rico=20Wang?= <xiyou.wangcong@gmail.com>
Date: Wed, 25 Mar 2009 00:07:19 +0800
Subject: kernel/module.c: fix an unused goto label

Impact: cleanup

Label 'free_init' is only used when defined(CONFIG_MODULE_UNLOAD) &&
defined(CONFIG_SMP), so move it inside to shut up gcc.

Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 kernel/module.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/module.c b/kernel/module.c
index b862fdb6a37..7af72bbe4cc 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2319,8 +2319,8 @@ static noinline struct module *load_module(void __user *umod,
 	ftrace_release(mod->module_core, mod->core_size);
  free_unload:
 	module_unload_free(mod);
- free_init:
 #if defined(CONFIG_MODULE_UNLOAD) && defined(CONFIG_SMP)
+ free_init:
 	percpu_modfree(mod->refptr);
 #endif
 	module_free(mod, mod->module_init);
-- 
cgit v1.2.3


From 414fd31b2553aaf160ca9b9afe45aa0372b01b92 Mon Sep 17 00:00:00 2001
From: Tim Abbott <tabbott@mit.edu>
Date: Fri, 5 Dec 2008 19:03:56 -0500
Subject: module: Make find_symbol return a struct kernel_symbol

Impact: Cleanup, internal API change

Ksplice needs access to the kernel_symbol structure in order to support
modifications to the exported symbol table.

Cc: Anders Kaseorg <andersk@mit.edu>
Cc: Jeff Arnold <jbarnold@mit.edu>
Signed-off-by: Tim Abbott <tabbott@mit.edu>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (bugfix and style)
---
 kernel/module.c | 75 ++++++++++++++++++++++++++++-----------------------------
 1 file changed, 37 insertions(+), 38 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 7af72bbe4cc..2f0fddf3c11 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -283,7 +283,7 @@ struct find_symbol_arg {
 	/* Output */
 	struct module *owner;
 	const unsigned long *crc;
-	unsigned long value;
+	const struct kernel_symbol *sym;
 };
 
 static bool find_symbol_in_section(const struct symsearch *syms,
@@ -324,17 +324,17 @@ static bool find_symbol_in_section(const struct symsearch *syms,
 
 	fsa->owner = owner;
 	fsa->crc = symversion(syms->crcs, symnum);
-	fsa->value = syms->start[symnum].value;
+	fsa->sym = &syms->start[symnum];
 	return true;
 }
 
-/* Find a symbol, return value, (optional) crc and (optional) module
- * which owns it */
-static unsigned long find_symbol(const char *name,
-				 struct module **owner,
-				 const unsigned long **crc,
-				 bool gplok,
-				 bool warn)
+/* Find a symbol and return it, along with, (optional) crc and
+ * (optional) module which owns it */
+static const struct kernel_symbol *find_symbol(const char *name,
+					       struct module **owner,
+					       const unsigned long **crc,
+					       bool gplok,
+					       bool warn)
 {
 	struct find_symbol_arg fsa;
 
@@ -347,11 +347,11 @@ static unsigned long find_symbol(const char *name,
 			*owner = fsa.owner;
 		if (crc)
 			*crc = fsa.crc;
-		return fsa.value;
+		return fsa.sym;
 	}
 
 	DEBUGP("Failed to find symbol %s\n", name);
-	return -ENOENT;
+	return NULL;
 }
 
 /* Search for module by name: must hold module_mutex. */
@@ -894,7 +894,7 @@ void __symbol_put(const char *symbol)
 	struct module *owner;
 
 	preempt_disable();
-	if (IS_ERR_VALUE(find_symbol(symbol, &owner, NULL, true, false)))
+	if (!find_symbol(symbol, &owner, NULL, true, false))
 		BUG();
 	module_put(owner);
 	preempt_enable();
@@ -1057,7 +1057,7 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs,
 {
 	const unsigned long *crc;
 
-	if (IS_ERR_VALUE(find_symbol("struct_module", NULL, &crc, true, false)))
+	if (!find_symbol("struct_module", NULL, &crc, true, false))
 		BUG();
 	return check_version(sechdrs, versindex, "struct_module", mod, crc);
 }
@@ -1098,25 +1098,25 @@ static inline int same_magic(const char *amagic, const char *bmagic,
 
 /* Resolve a symbol for this module.  I.e. if we find one, record usage.
    Must be holding module_mutex. */
-static unsigned long resolve_symbol(Elf_Shdr *sechdrs,
-				    unsigned int versindex,
-				    const char *name,
-				    struct module *mod)
+static const struct kernel_symbol *resolve_symbol(Elf_Shdr *sechdrs,
+						  unsigned int versindex,
+						  const char *name,
+						  struct module *mod)
 {
 	struct module *owner;
-	unsigned long ret;
+	const struct kernel_symbol *sym;
 	const unsigned long *crc;
 
-	ret = find_symbol(name, &owner, &crc,
+	sym = find_symbol(name, &owner, &crc,
 			  !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true);
-	if (!IS_ERR_VALUE(ret)) {
-		/* use_module can fail due to OOM,
-		   or module initialization or unloading */
+	/* use_module can fail due to OOM,
+	   or module initialization or unloading */
+	if (sym) {
 		if (!check_version(sechdrs, versindex, name, mod, crc) ||
 		    !use_module(mod, owner))
-			ret = -EINVAL;
+			sym = NULL;
 	}
-	return ret;
+	return sym;
 }
 
 /*
@@ -1516,17 +1516,15 @@ static void free_module(struct module *mod)
 void *__symbol_get(const char *symbol)
 {
 	struct module *owner;
-	unsigned long value;
+	const struct kernel_symbol *sym;
 
 	preempt_disable();
-	value = find_symbol(symbol, &owner, NULL, true, true);
-	if (IS_ERR_VALUE(value))
-		value = 0;
-	else if (strong_try_module_get(owner))
-		value = 0;
+	sym = find_symbol(symbol, &owner, NULL, true, true);
+	if (sym && strong_try_module_get(owner))
+		sym = NULL;
 	preempt_enable();
 
-	return (void *)value;
+	return sym ? (void *)sym->value : NULL;
 }
 EXPORT_SYMBOL_GPL(__symbol_get);
 
@@ -1554,8 +1552,7 @@ static int verify_export_symbols(struct module *mod)
 
 	for (i = 0; i < ARRAY_SIZE(arr); i++) {
 		for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
-			if (!IS_ERR_VALUE(find_symbol(s->name, &owner,
-						      NULL, true, false))) {
+			if (find_symbol(s->name, &owner, NULL, true, false)) {
 				printk(KERN_ERR
 				       "%s: exports duplicate symbol %s"
 				       " (owned by %s)\n",
@@ -1579,6 +1576,7 @@ static int simplify_symbols(Elf_Shdr *sechdrs,
 	unsigned long secbase;
 	unsigned int i, n = sechdrs[symindex].sh_size / sizeof(Elf_Sym);
 	int ret = 0;
+	const struct kernel_symbol *ksym;
 
 	for (i = 1; i < n; i++) {
 		switch (sym[i].st_shndx) {
@@ -1598,13 +1596,14 @@ static int simplify_symbols(Elf_Shdr *sechdrs,
 			break;
 
 		case SHN_UNDEF:
-			sym[i].st_value
-			  = resolve_symbol(sechdrs, versindex,
-					   strtab + sym[i].st_name, mod);
-
+			ksym = resolve_symbol(sechdrs, versindex,
+					      strtab + sym[i].st_name, mod);
 			/* Ok if resolved.  */
-			if (!IS_ERR_VALUE(sym[i].st_value))
+			if (ksym) {
+				sym[i].st_value = ksym->value;
 				break;
+			}
+
 			/* Ok if weak.  */
 			if (ELF_ST_BIND(sym[i].st_info) == STB_WEAK)
 				break;
-- 
cgit v1.2.3


From e610499e2656e61975affd0af56b26eb73964c84 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Tue, 31 Mar 2009 13:05:31 -0600
Subject: module: __module_address

Impact: New API, cleanup

ksplice wants to know the bounds of a module, not just the module text.

It makes sense to have __module_address.  We then implement
is_module_address and __module_text_address in terms of this (and
change is_module_text_address() to bool while we're at it).

Also, add proper kerneldoc for them all.

Cc: Anders Kaseorg <andersk@mit.edu>
Cc: Jeff Arnold <jbarnold@mit.edu>
Cc: Tim Abbott <tabbott@mit.edu>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 include/linux/module.h | 20 +++++++++----
 kernel/module.c        | 76 ++++++++++++++++++++++++++++++++++++++------------
 2 files changed, 73 insertions(+), 23 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index 08e5e75d612..fd1241e1416 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -365,7 +365,9 @@ static inline int module_is_live(struct module *mod)
 /* Is this address in a module? (second is with no locks, for oops) */
 struct module *module_text_address(unsigned long addr);
 struct module *__module_text_address(unsigned long addr);
-int is_module_address(unsigned long addr);
+struct module *__module_address(unsigned long addr);
+bool is_module_address(unsigned long addr);
+bool is_module_text_address(unsigned long addr);
 
 static inline int within_module_core(unsigned long addr, struct module *mod)
 {
@@ -494,21 +496,29 @@ search_module_extables(unsigned long addr)
 	return NULL;
 }
 
-/* Is this address in a module? */
 static inline struct module *module_text_address(unsigned long addr)
 {
 	return NULL;
 }
 
-/* Is this address in a module? (don't take a lock, we're oopsing) */
+static inline struct module *__module_address(unsigned long addr)
+{
+	return NULL;
+}
+
 static inline struct module *__module_text_address(unsigned long addr)
 {
 	return NULL;
 }
 
-static inline int is_module_address(unsigned long addr)
+static inline bool is_module_address(unsigned long addr)
 {
-	return 0;
+	return false;
+}
+
+static inline bool is_module_text_address(unsigned long addr)
+{
+	return false;
 }
 
 /* Get/put a kernel symbol (calls should be symmetric) */
diff --git a/kernel/module.c b/kernel/module.c
index 2f0fddf3c11..bd15a94f91c 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -76,7 +76,7 @@ static DECLARE_WAIT_QUEUE_HEAD(module_wq);
 
 static BLOCKING_NOTIFIER_HEAD(module_notify_list);
 
-/* Bounds of module allocation, for speeding __module_text_address */
+/* Bounds of module allocation, for speeding __module_address */
 static unsigned long module_addr_min = -1UL, module_addr_max = 0;
 
 int register_module_notifier(struct notifier_block * nb)
@@ -2745,29 +2745,31 @@ const struct exception_table_entry *search_module_extables(unsigned long addr)
 }
 
 /*
- * Is this a valid module address?
+ * is_module_address - is this address inside a module?
+ * @addr: the address to check.
+ *
+ * See is_module_text_address() if you simply want to see if the address
+ * is code (not data).
  */
-int is_module_address(unsigned long addr)
+bool is_module_address(unsigned long addr)
 {
-	struct module *mod;
+	bool ret;
 
 	preempt_disable();
-
-	list_for_each_entry_rcu(mod, &modules, list) {
-		if (within_module_core(addr, mod)) {
-			preempt_enable();
-			return 1;
-		}
-	}
-
+	ret = __module_address(addr) != NULL;
 	preempt_enable();
 
-	return 0;
+	return ret;
 }
 
-
-/* Is this a valid kernel address? */
-__notrace_funcgraph struct module *__module_text_address(unsigned long addr)
+/*
+ * __module_address - get the module which contains an address.
+ * @addr: the address.
+ *
+ * Must be called with preempt disabled or module mutex held so that
+ * module doesn't get freed during this.
+ */
+__notrace_funcgraph struct module *__module_address(unsigned long addr)
 {
 	struct module *mod;
 
@@ -2775,12 +2777,50 @@ __notrace_funcgraph struct module *__module_text_address(unsigned long addr)
 		return NULL;
 
 	list_for_each_entry_rcu(mod, &modules, list)
-		if (within(addr, mod->module_init, mod->init_text_size)
-		    || within(addr, mod->module_core, mod->core_text_size))
+		if (within_module_core(addr, mod)
+		    || within_module_init(addr, mod))
 			return mod;
 	return NULL;
 }
 
+/*
+ * is_module_text_address - is this address inside module code?
+ * @addr: the address to check.
+ *
+ * See is_module_address() if you simply want to see if the address is
+ * anywhere in a module.  See kernel_text_address() for testing if an
+ * address corresponds to kernel or module code.
+ */
+bool is_module_text_address(unsigned long addr)
+{
+	bool ret;
+
+	preempt_disable();
+	ret = __module_text_address(addr) != NULL;
+	preempt_enable();
+
+	return ret;
+}
+
+/*
+ * __module_text_address - get the module whose code contains an address.
+ * @addr: the address.
+ *
+ * Must be called with preempt disabled or module mutex held so that
+ * module doesn't get freed during this.
+ */
+struct module *__module_text_address(unsigned long addr)
+{
+	struct module *mod = __module_address(addr);
+	if (mod) {
+		/* Make sure it's within the text section. */
+		if (!within(addr, mod->module_init, mod->init_text_size)
+		    && !within(addr, mod->module_core, mod->core_text_size))
+			mod = NULL;
+	}
+	return mod;
+}
+
 struct module *module_text_address(unsigned long addr)
 {
 	struct module *mod;
-- 
cgit v1.2.3


From a6e6abd575fcbe6572ebc7a70ad616406d206fa8 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Tue, 31 Mar 2009 13:05:31 -0600
Subject: module: remove module_text_address()

Impact: Replace and remove risky (non-EXPORTed) API

module_text_address() returns a pointer to the module, which given locking
improvements in module.c, is useless except to test for NULL:

1) If the module can't go away, use __module_text_address.
2) Otherwise, just use is_module_text_address().

Cc: linux-mtd@lists.infradead.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 drivers/mtd/nand/nand_base.c |  4 ++--
 include/linux/module.h       |  7 -------
 kernel/extable.c             |  6 +++---
 kernel/module.c              | 17 ++++-------------
 4 files changed, 9 insertions(+), 25 deletions(-)

diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
index 0c3afccde8a..5f71371eb1b 100644
--- a/drivers/mtd/nand/nand_base.c
+++ b/drivers/mtd/nand/nand_base.c
@@ -2720,14 +2720,14 @@ int nand_scan_tail(struct mtd_info *mtd)
 	return chip->scan_bbt(mtd);
 }
 
-/* module_text_address() isn't exported, and it's mostly a pointless
+/* is_module_text_address() isn't exported, and it's mostly a pointless
    test if this is a module _anyway_ -- they'd have to try _really_ hard
    to call us from in-kernel code if the core NAND support is modular. */
 #ifdef MODULE
 #define caller_is_module() (1)
 #else
 #define caller_is_module() \
-	module_text_address((unsigned long)__builtin_return_address(0))
+	is_module_text_address((unsigned long)__builtin_return_address(0))
 #endif
 
 /**
diff --git a/include/linux/module.h b/include/linux/module.h
index fd1241e1416..69761ce0dbf 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -362,8 +362,6 @@ static inline int module_is_live(struct module *mod)
 	return mod->state != MODULE_STATE_GOING;
 }
 
-/* Is this address in a module? (second is with no locks, for oops) */
-struct module *module_text_address(unsigned long addr);
 struct module *__module_text_address(unsigned long addr);
 struct module *__module_address(unsigned long addr);
 bool is_module_address(unsigned long addr);
@@ -496,11 +494,6 @@ search_module_extables(unsigned long addr)
 	return NULL;
 }
 
-static inline struct module *module_text_address(unsigned long addr)
-{
-	return NULL;
-}
-
 static inline struct module *__module_address(unsigned long addr)
 {
 	return NULL;
diff --git a/kernel/extable.c b/kernel/extable.c
index e136ed8d82b..384f0da8a03 100644
--- a/kernel/extable.c
+++ b/kernel/extable.c
@@ -58,14 +58,14 @@ __notrace_funcgraph int __kernel_text_address(unsigned long addr)
 {
 	if (core_kernel_text(addr))
 		return 1;
-	return __module_text_address(addr) != NULL;
+	return is_module_text_address(addr);
 }
 
 int kernel_text_address(unsigned long addr)
 {
 	if (core_kernel_text(addr))
 		return 1;
-	return module_text_address(addr) != NULL;
+	return is_module_text_address(addr);
 }
 
 /*
@@ -81,5 +81,5 @@ int func_ptr_is_kernel_text(void *ptr)
 	addr = (unsigned long) dereference_function_descriptor(ptr);
 	if (core_kernel_text(addr))
 		return 1;
-	return module_text_address(addr) != NULL;
+	return is_module_text_address(addr);
 }
diff --git a/kernel/module.c b/kernel/module.c
index bd15a94f91c..8ddca629e07 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -908,8 +908,10 @@ void symbol_put_addr(void *addr)
 	if (core_kernel_text((unsigned long)addr))
 		return;
 
-	if (!(modaddr = module_text_address((unsigned long)addr)))
-		BUG();
+	/* module_text_address is safe here: we're supposed to have reference
+	 * to module from symbol_get, so it can't go away. */
+	modaddr = __module_text_address((unsigned long)addr);
+	BUG_ON(!modaddr);
 	module_put(modaddr);
 }
 EXPORT_SYMBOL_GPL(symbol_put_addr);
@@ -2821,17 +2823,6 @@ struct module *__module_text_address(unsigned long addr)
 	return mod;
 }
 
-struct module *module_text_address(unsigned long addr)
-{
-	struct module *mod;
-
-	preempt_disable();
-	mod = __module_text_address(addr);
-	preempt_enable();
-
-	return mod;
-}
-
 /* Don't grab lock, we're oopsing. */
 void print_modules(void)
 {
-- 
cgit v1.2.3


From 75a66614db21007bcc8c37f9c5d5b922981387b9 Mon Sep 17 00:00:00 2001
From: Anders Kaseorg <andersk@mit.edu>
Date: Fri, 5 Dec 2008 19:03:58 -0500
Subject: Ksplice: Add functions for walking kallsyms symbols

Impact: New API

kallsyms_lookup_name only returns the first match that it finds.  Ksplice
needs information about all symbols with a given name in order to correctly
resolve local symbols.

kallsyms_on_each_symbol provides a generic mechanism for iterating over the
kallsyms table.

Cc: Jeff Arnold <jbarnold@mit.edu>
Cc: Tim Abbott <tabbott@mit.edu>
Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 include/linux/kallsyms.h | 15 +++++++++++++++
 include/linux/module.h   | 12 ++++++++++++
 kernel/kallsyms.c        | 19 +++++++++++++++++++
 kernel/module.c          | 19 +++++++++++++++++++
 4 files changed, 65 insertions(+)

diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index f3fe34391d8..792274269f2 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -13,10 +13,17 @@
 #define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s]") + (KSYM_NAME_LEN - 1) + \
 			 2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + 1)
 
+struct module;
+
 #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);
+
 extern int kallsyms_lookup_size_offset(unsigned long addr,
 				  unsigned long *symbolsize,
 				  unsigned long *offset);
@@ -43,6 +50,14 @@ 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)
diff --git a/include/linux/module.h b/include/linux/module.h
index 69761ce0dbf..c3d3fc4ffb1 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -387,6 +387,10 @@ 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 __module_put_and_exit(struct module *mod, long code)
 	__attribute__((noreturn));
 #define module_put_and_exit(code) __module_put_and_exit(THIS_MODULE, code);
@@ -566,6 +570,14 @@ 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 */
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 7b8b0f21a5b..374faf9bfdc 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -161,6 +161,25 @@ unsigned long kallsyms_lookup_name(const char *name)
 	return module_kallsyms_lookup_name(name);
 }
 
+int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *,
+				      unsigned long),
+			    void *data)
+{
+	char namebuf[KSYM_NAME_LEN];
+	unsigned long i;
+	unsigned int off;
+	int ret;
+
+	for (i = 0, off = 0; i < kallsyms_num_syms; i++) {
+		off = kallsyms_expand_symbol(off, namebuf);
+		ret = fn(data, namebuf, NULL, kallsyms_addresses[i]);
+		if (ret != 0)
+			return ret;
+	}
+	return module_kallsyms_on_each_symbol(fn, data);
+}
+EXPORT_SYMBOL_GPL(kallsyms_on_each_symbol);
+
 static unsigned long get_symbol_pos(unsigned long addr,
 				    unsigned long *symbolsize,
 				    unsigned long *offset)
diff --git a/kernel/module.c b/kernel/module.c
index 8ddca629e07..dd4389be915 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2612,6 +2612,25 @@ unsigned long module_kallsyms_lookup_name(const char *name)
 	preempt_enable();
 	return ret;
 }
+
+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;
+
+	list_for_each_entry(mod, &modules, list) {
+		for (i = 0; i < mod->num_symtab; i++) {
+			ret = fn(data, mod->strtab + mod->symtab[i].st_name,
+				 mod, mod->symtab[i].st_value);
+			if (ret != 0)
+				return ret;
+		}
+	}
+	return 0;
+}
 #endif /* CONFIG_KALLSYMS */
 
 static char *module_flags(struct module *mod, char *buf)
-- 
cgit v1.2.3


From c6b37801911d7f4663c99cad8aa230bc934cea82 Mon Sep 17 00:00:00 2001
From: Tim Abbott <tabbott@mit.edu>
Date: Fri, 5 Dec 2008 19:03:59 -0500
Subject: module: Export symbols needed for Ksplice

Impact: Expose some module.c symbols

Ksplice uses several functions from module.c in order to resolve
symbols and implement dependency handling.  Calling these functions
requires holding module_mutex, so it is exported.

(This is just the module part of a bigger add-exports patch from Tim).

Cc: Anders Kaseorg <andersk@mit.edu>
Cc: Jeff Arnold <jbarnold@mit.edu>
Signed-off-by: Tim Abbott <tabbott@mit.edu>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 include/linux/module.h | 28 ++++++++++++++++++++++++++++
 kernel/module.c        | 43 +++++++++++++++++++------------------------
 2 files changed, 47 insertions(+), 24 deletions(-)

diff --git a/include/linux/module.h b/include/linux/module.h
index c3d3fc4ffb1..d246da0b0f8 100644
--- a/include/linux/module.h
+++ b/include/linux/module.h
@@ -354,6 +354,8 @@ struct module
 #define MODULE_ARCH_INIT {}
 #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.*/
@@ -379,6 +381,31 @@ static inline int within_module_init(unsigned long addr, struct module *mod)
 	       addr < (unsigned long)mod->module_init + mod->init_size;
 }
 
+/* Search for module by name: must hold module_mutex. */
+struct module *find_module(const char *name);
+
+struct symsearch {
+	const struct kernel_symbol *start, *stop;
+	const unsigned long *crcs;
+	enum {
+		NOT_GPL_ONLY,
+		GPL_ONLY,
+		WILL_BE_GPL_ONLY,
+	} licence;
+	bool unused;
+};
+
+/* Search for an exported symbol by name. */
+const struct kernel_symbol *find_symbol(const char *name,
+					struct module **owner,
+					const unsigned long **crc,
+					bool gplok,
+					bool warn);
+
+/* Walk the exported symbol table */
+bool each_symbol(bool (*fn)(const struct symsearch *arr, struct module *owner,
+			    unsigned int symnum, void *data), void *data);
+
 /* 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,
@@ -452,6 +479,7 @@ static inline void __module_get(struct module *module)
 #define symbol_put_addr(p) do { } while(0)
 
 #endif /* CONFIG_MODULE_UNLOAD */
+int use_module(struct module *a, struct module *b);
 
 /* This is a #define so the string doesn't get put in every .o file */
 #define module_name(mod)			\
diff --git a/kernel/module.c b/kernel/module.c
index dd4389be915..5fd00766a4d 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -68,7 +68,8 @@
 
 /* List of modules, protected by module_mutex or preempt_disable
  * (delete uses stop_machine/add uses RCU list operations). */
-static DEFINE_MUTEX(module_mutex);
+DEFINE_MUTEX(module_mutex);
+EXPORT_SYMBOL_GPL(module_mutex);
 static LIST_HEAD(modules);
 
 /* Waiting for a module to finish initializing? */
@@ -186,17 +187,6 @@ extern const unsigned long __start___kcrctab_unused_gpl[];
 #define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
 #endif
 
-struct symsearch {
-	const struct kernel_symbol *start, *stop;
-	const unsigned long *crcs;
-	enum {
-		NOT_GPL_ONLY,
-		GPL_ONLY,
-		WILL_BE_GPL_ONLY,
-	} licence;
-	bool unused;
-};
-
 static bool each_symbol_in_section(const struct symsearch *arr,
 				   unsigned int arrsize,
 				   struct module *owner,
@@ -217,10 +207,8 @@ static bool each_symbol_in_section(const struct symsearch *arr,
 }
 
 /* Returns true as soon as fn returns true, otherwise false. */
-static bool each_symbol(bool (*fn)(const struct symsearch *arr,
-				   struct module *owner,
-				   unsigned int symnum, void *data),
-			void *data)
+bool each_symbol(bool (*fn)(const struct symsearch *arr, struct module *owner,
+			    unsigned int symnum, void *data), void *data)
 {
 	struct module *mod;
 	const struct symsearch arr[] = {
@@ -273,6 +261,7 @@ static bool each_symbol(bool (*fn)(const struct symsearch *arr,
 	}
 	return false;
 }
+EXPORT_SYMBOL_GPL(each_symbol);
 
 struct find_symbol_arg {
 	/* Input */
@@ -330,11 +319,11 @@ static bool find_symbol_in_section(const struct symsearch *syms,
 
 /* Find a symbol and return it, along with, (optional) crc and
  * (optional) module which owns it */
-static const struct kernel_symbol *find_symbol(const char *name,
-					       struct module **owner,
-					       const unsigned long **crc,
-					       bool gplok,
-					       bool warn)
+const struct kernel_symbol *find_symbol(const char *name,
+					struct module **owner,
+					const unsigned long **crc,
+					bool gplok,
+					bool warn)
 {
 	struct find_symbol_arg fsa;
 
@@ -353,9 +342,10 @@ static const struct kernel_symbol *find_symbol(const char *name,
 	DEBUGP("Failed to find symbol %s\n", name);
 	return NULL;
 }
+EXPORT_SYMBOL_GPL(find_symbol);
 
 /* Search for module by name: must hold module_mutex. */
-static struct module *find_module(const char *name)
+struct module *find_module(const char *name)
 {
 	struct module *mod;
 
@@ -365,6 +355,7 @@ static struct module *find_module(const char *name)
 	}
 	return NULL;
 }
+EXPORT_SYMBOL_GPL(find_module);
 
 #ifdef CONFIG_SMP
 
@@ -641,7 +632,7 @@ static int already_uses(struct module *a, struct module *b)
 }
 
 /* Module a uses b */
-static int use_module(struct module *a, struct module *b)
+int use_module(struct module *a, struct module *b)
 {
 	struct module_use *use;
 	int no_warn, err;
@@ -674,6 +665,7 @@ static int use_module(struct module *a, struct module *b)
 	no_warn = sysfs_create_link(b->holders_dir, &a->mkobj.kobj, a->name);
 	return 1;
 }
+EXPORT_SYMBOL_GPL(use_module);
 
 /* Clear the unload stuff of the module. */
 static void module_unload_free(struct module *mod)
@@ -951,10 +943,11 @@ static inline void module_unload_free(struct module *mod)
 {
 }
 
-static inline int use_module(struct module *a, struct module *b)
+int use_module(struct module *a, struct module *b)
 {
 	return strong_try_module_get(b) == 0;
 }
+EXPORT_SYMBOL_GPL(use_module);
 
 static inline void module_unload_init(struct module *mod)
 {
@@ -2803,6 +2796,7 @@ __notrace_funcgraph struct module *__module_address(unsigned long addr)
 			return mod;
 	return NULL;
 }
+EXPORT_SYMBOL_GPL(__module_address);
 
 /*
  * is_module_text_address - is this address inside module code?
@@ -2841,6 +2835,7 @@ struct module *__module_text_address(unsigned long addr)
 	}
 	return mod;
 }
+EXPORT_SYMBOL_GPL(__module_text_address);
 
 /* Don't grab lock, we're oopsing. */
 void print_modules(void)
-- 
cgit v1.2.3


From c6e665c8f0c18ab3686117905765b5139efd6ebd Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Tue, 31 Mar 2009 13:05:33 -0600
Subject: module: clarify the force-loading taint message.

Impact: Message cleanup

Two of three callers of try_to_force_load() are not because of a
missing version, so change the messages:

Old:
	<modname>: no version for "magic" found: kernel tainted.
New:
	<modname>: bad vermagic: kernel tainted.

Old:
	<modname>: no version for "nocrc" found: kernel tainted.
New:
	<modname>: no versions for exported symbols: kernel tainted.

Old:
	<modname>: no version for "<symname>" found: kernel tainted.
New:
	<modname>: <symname>: kernel tainted.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 kernel/module.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 5fd00766a4d..599fc85bd2c 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -990,12 +990,12 @@ static struct module_attribute *modinfo_attrs[] = {
 
 static const char vermagic[] = VERMAGIC_STRING;
 
-static int try_to_force_load(struct module *mod, const char *symname)
+static int try_to_force_load(struct module *mod, const char *reason)
 {
 #ifdef CONFIG_MODULE_FORCE_LOAD
 	if (!test_taint(TAINT_FORCED_MODULE))
-		printk("%s: no version for \"%s\" found: kernel tainted.\n",
-		       mod->name, symname);
+		printk(KERN_WARNING "%s: %s: kernel tainted.\n",
+		       mod->name, reason);
 	add_taint_module(mod, TAINT_FORCED_MODULE);
 	return 0;
 #else
@@ -2002,7 +2002,7 @@ static noinline struct module *load_module(void __user *umod,
 	modmagic = get_modinfo(sechdrs, infoindex, "vermagic");
 	/* This is allowed: modprobe --force will invalidate it. */
 	if (!modmagic) {
-		err = try_to_force_load(mod, "magic");
+		err = try_to_force_load(mod, "bad vermagic");
 		if (err)
 			goto free_hdr;
 	} else if (!same_magic(modmagic, vermagic, versindex)) {
@@ -2191,8 +2191,8 @@ static noinline struct module *load_module(void __user *umod,
 	    || (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
 #endif
 		) {
-		printk(KERN_WARNING "%s: No versions for exported symbols.\n", mod->name);
-		err = try_to_force_load(mod, "nocrc");
+		err = try_to_force_load(mod,
+					"no versions for exported symbols");
 		if (err)
 			goto cleanup;
 	}
-- 
cgit v1.2.3


From 9cb610d8e35fe3ec95a2fe2030b02f85aeea83c1 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Tue, 31 Mar 2009 13:05:33 -0600
Subject: module: remove the SHF_ALLOC flag on the __versions section.

Impact: reduce kernel memory usage

This patch just takes off the SHF_ALLOC flag on __versions so we don't
keep them around after module load.

This saves about 7% of module memory if CONFIG_MODVERSIONS=y.

Cc: Shawn Bohrer <shawn.bohrer@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 kernel/module.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kernel/module.c b/kernel/module.c
index 599fc85bd2c..784bf6d8f8c 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1961,6 +1961,9 @@ static noinline struct module *load_module(void __user *umod,
 		if (strncmp(secstrings+sechdrs[i].sh_name, ".exit", 5) == 0)
 			sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
 #endif
+		/* Don't keep __versions around; it's just for loading. */
+		if (strcmp(secstrings + sechdrs[i].sh_name, "__versions") == 0)
+			sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
 	}
 
 	modindex = find_sec(hdr, sechdrs, secstrings,
-- 
cgit v1.2.3


From 8c8ef42aee8fcfb4128bb94c50d55c9f80ade525 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Tue, 31 Mar 2009 13:05:34 -0600
Subject: module: include other structures in module version check

With CONFIG_MODVERSIONS, we version 'struct module' using a dummy
export, but other things matter too:

1) 'struct modversion_info' determines the layout of the __versions section,
2) 'struct kernel_param' determines the layout of the __params section,
3) 'struct kernel_symbol' determines __ksymtab*.
4) 'struct marker' determines __markers.
5) 'struct tracepoint' determines __tracepoints.

So we rename 'struct_module' to 'module_layout' and include these in
the signature.  Now it's general we can add others later on without
confusion.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 kernel/module.c       | 18 +++++++++++++-----
 scripts/mod/modpost.c |  4 ++--
 2 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 784bf6d8f8c..e8cf636e614 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1052,9 +1052,9 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs,
 {
 	const unsigned long *crc;
 
-	if (!find_symbol("struct_module", NULL, &crc, true, false))
+	if (!find_symbol("module_layout", NULL, &crc, true, false))
 		BUG();
-	return check_version(sechdrs, versindex, "struct_module", mod, crc);
+	return check_version(sechdrs, versindex, "module_layout", mod, crc);
 }
 
 /* First part is kernel version, which we ignore if module has crcs. */
@@ -2858,9 +2858,17 @@ void print_modules(void)
 }
 
 #ifdef CONFIG_MODVERSIONS
-/* Generate the signature for struct module here, too, for modversions. */
-void struct_module(struct module *mod) { return; }
-EXPORT_SYMBOL(struct_module);
+/* Generate the signature for all relevant module structures here.
+ * If these change, we don't want to try to parse the module. */
+void module_layout(struct module *mod,
+		   struct modversion_info *ver,
+		   struct kernel_param *kp,
+		   struct kernel_symbol *ks,
+		   struct marker *marker,
+		   struct tracepoint *tp)
+{
+}
+EXPORT_SYMBOL(module_layout);
 #endif
 
 #ifdef CONFIG_MARKERS
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 7e62303133d..8cc70612984 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -1607,12 +1607,12 @@ static void read_symbols(char *modname)
 
 	parse_elf_finish(&info);
 
-	/* Our trick to get versioning for struct_module - it's
+	/* Our trick to get versioning for module struct etc. - it's
 	 * never passed as an argument to an exported function, so
 	 * the automatic versioning doesn't pick it up, but it's really
 	 * important anyhow */
 	if (modversions)
-		mod->unres = alloc_symbol("struct_module", 0, mod->unres);
+		mod->unres = alloc_symbol("module_layout", 0, mod->unres);
 }
 
 #define SZ 500
-- 
cgit v1.2.3


From acae05156551fd7528fbb616271e672789388e3c Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Sun, 8 Feb 2009 10:42:01 -0800
Subject: module: create a request_module_nowait()

There seems to be a common pattern in the kernel where drivers want to
call request_module() from inside a module_init() function. Currently
this would deadlock.

As a result, several drivers go through hoops like scheduling things via
kevent, or creating custom work queues (because kevent can deadlock on them).

This patch changes this to use a request_module_nowait() function macro instead,
which just fires the modprobe off but doesn't wait for it, and thus avoids the
original deadlock entirely.

On my laptop this already results in one less kernel thread running..

(Includes Jiri's patch to use enum umh_wait)

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (bool-ified)
Cc: Jiri Slaby <jirislaby@gmail.com>
---
 include/linux/kmod.h | 11 ++++++++---
 kernel/kmod.c        | 10 ++++++----
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/include/linux/kmod.h b/include/linux/kmod.h
index 92213a9194e..d5fa565086d 100644
--- a/include/linux/kmod.h
+++ b/include/linux/kmod.h
@@ -29,10 +29,15 @@
 #ifdef CONFIG_MODULES
 /* modprobe exit status on success, -ve on error.  Return value
  * usually useless though. */
-extern int request_module(const char * name, ...) __attribute__ ((format (printf, 1, 2)));
-#define try_then_request_module(x, mod...) ((x) ?: (request_module(mod), (x)))
+extern int __request_module(bool wait, const char *name, ...) \
+	__attribute__((format(printf, 2, 3)));
+#define request_module(mod...) __request_module(true, mod)
+#define request_module_nowait(mod...) __request_module(false, mod)
+#define try_then_request_module(x, mod...) \
+	((x) ?: (__request_module(false, mod), (x)))
 #else
-static inline int request_module(const char * name, ...) { return -ENOSYS; }
+static inline int request_module(const char *name, ...) { return -ENOSYS; }
+static inline int request_module_nowait(const char *name, ...) { return -ENOSYS; }
 #define try_then_request_module(x, mod...) (x)
 #endif
 
diff --git a/kernel/kmod.c b/kernel/kmod.c
index f0c8f545180..b750675251e 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -50,7 +50,8 @@ static struct workqueue_struct *khelper_wq;
 char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe";
 
 /**
- * request_module - try to load a kernel module
+ * __request_module - try to load a kernel module
+ * @wait: wait (or not) for the operation to complete
  * @fmt: printf style format string for the name of the module
  * @...: arguments as specified in the format string
  *
@@ -63,7 +64,7 @@ char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe";
  * If module auto-loading support is disabled then this function
  * becomes a no-operation.
  */
-int request_module(const char *fmt, ...)
+int __request_module(bool wait, const char *fmt, ...)
 {
 	va_list args;
 	char module_name[MODULE_NAME_LEN];
@@ -108,11 +109,12 @@ int request_module(const char *fmt, ...)
 		return -ENOMEM;
 	}
 
-	ret = call_usermodehelper(modprobe_path, argv, envp, 1);
+	ret = call_usermodehelper(modprobe_path, argv, envp,
+			wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC);
 	atomic_dec(&kmod_concurrent);
 	return ret;
 }
-EXPORT_SYMBOL(request_module);
+EXPORT_SYMBOL(__request_module);
 #endif /* CONFIG_MODULES */
 
 struct subprocess_info {
-- 
cgit v1.2.3


From e91defa26c527ceeaff6266c55cdc7e17c9081a2 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Tue, 31 Mar 2009 13:05:35 -0600
Subject: module: don't use stop_machine on module load

Kay Sievers <kay.sievers@vrfy.org> discovered that boot times are slowed
by about half a second because all the stop_machine_create() calls,
and he only probes about 40 modules (I have 125 loaded on this laptop).

We only do stop_machine_create() so we can unlink the module if
something goes wrong, but it's overkill (and buggy anyway: if
stop_machine_create() fails we still call stop_machine_destroy()).

Since we are only protecting against kallsyms (esp. oops) walking the
list, synchronize_sched() is sufficient (synchronize_rcu() is probably
sufficient, but we're not in a hurry).

Kay says of this patch:
	... no module takes more than 40 millisecs to link now, most of
	them are between 3 and 8 millisecs.

	That looks very different to the numbers without this patch
	and the otherwise same setup, where we get heavy noise in the
	traces and many delays of up to 200 millisecs until linking,
	most of them taking 30+ millisecs.

Tested-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 kernel/module.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index e8cf636e614..1a9a3986b13 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1912,12 +1912,6 @@ static noinline struct module *load_module(void __user *umod,
 	if (len > 64 * 1024 * 1024 || (hdr = vmalloc(len)) == NULL)
 		return ERR_PTR(-ENOMEM);
 
-	/* Create stop_machine threads since the error path relies on
-	 * a non-failing stop_machine call. */
-	err = stop_machine_create();
-	if (err)
-		goto free_hdr;
-
 	if (copy_from_user(hdr, umod, len) != 0) {
 		err = -EFAULT;
 		goto free_hdr;
@@ -2303,12 +2297,13 @@ static noinline struct module *load_module(void __user *umod,
 	/* Get rid of temporary copy */
 	vfree(hdr);
 
-	stop_machine_destroy();
 	/* Done! */
 	return mod;
 
  unlink:
-	stop_machine(__unlink_module, mod, NULL);
+	/* Unlink carefully: kallsyms could be walking list. */
+	list_del_rcu(&mod->list);
+	synchronize_sched();
 	module_arch_cleanup(mod);
  cleanup:
 	kobject_del(&mod->mkobj.kobj);
@@ -2331,7 +2326,6 @@ static noinline struct module *load_module(void __user *umod,
 	kfree(args);
  free_hdr:
 	vfree(hdr);
-	stop_machine_destroy();
 	return ERR_PTR(err);
 
  truncated:
-- 
cgit v1.2.3


From aa0d3bb77e780054babcd289484cf4c15180111b Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Tue, 31 Mar 2009 13:05:35 -0600
Subject: arm: allow usage of string functions in linux/string.h

In introducing a trivial "strstarts()" function in linux/string.h, we
hit:

	arch/arm/boot/compressed/misc.o: In function `strstarts':
	misc.c:(.text+0x368): undefined reference to `strlen'
	misc.c:(.text+0x378): undefined reference to `strncmp'

This is because of "CFLAGS_misc.o := -Dstatic=" in the Makefile.
"static inline strstarts(...)" becomes non-inline, and refers to the
other string ops.

The simplest workaround is to include asm/string.h.  This makes sense
anyway, since lib/string.c won't be linked against this so we can't
use those functions anyway.

Compile tested here.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
 arch/arm/boot/compressed/misc.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arm/boot/compressed/misc.c b/arch/arm/boot/compressed/misc.c
index 393c8164131..9e6e512f011 100644
--- a/arch/arm/boot/compressed/misc.c
+++ b/arch/arm/boot/compressed/misc.c
@@ -18,7 +18,10 @@
 
 unsigned int __machine_arch_type;
 
-#include <linux/string.h>
+#include <linux/compiler.h>	/* for inline */
+#include <linux/types.h>	/* for size_t */
+#include <linux/stddef.h>	/* for NULL */
+#include <asm/string.h>
 
 #ifdef STANDALONE_DEBUG
 #define putstr printf
-- 
cgit v1.2.3


From 66f92cf9d415e96a5bdd6c64de8dd8418595d2fc Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Tue, 31 Mar 2009 13:05:36 -0600
Subject: strstarts: helper function for !strncmp(str, prefix, strlen(prefix))

Impact: minor new API

ksplice added a "starts_with" function, which seems like a common need.
When people open-code it they seem to use fixed numbers rather than strlen,
so it's quite a readability win (also, strncmp() almost always wants != 0
on it).

So here's strstarts().

Cc: Anders Kaseorg <andersk@mit.edu>
Cc: Jeff Arnold <jbarnold@mit.edu>
Cc: Tim Abbott <tabbott@mit.edu>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 include/linux/string.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/linux/string.h b/include/linux/string.h
index d18fc198aa2..76ec218bb30 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -114,5 +114,14 @@ extern bool sysfs_streq(const char *s1, const char *s2);
 extern ssize_t memory_read_from_buffer(void *to, size_t count, loff_t *ppos,
 			const void *from, size_t available);
 
+/**
+ * strstarts - does @str start with @prefix?
+ * @str: string to examine
+ * @prefix: prefix to look for.
+ */
+static inline bool strstarts(const char *str, const char *prefix)
+{
+	return strncmp(str, prefix, strlen(prefix)) == 0;
+}
 #endif
 #endif /* _LINUX_STRING_H_ */
-- 
cgit v1.2.3


From 49502677e11079c2e3e01867c922a894ce06a8be Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Tue, 31 Mar 2009 13:05:36 -0600
Subject: module: use strstarts()

Impact: minor cleanup.

I'm not going to neaten anyone else's code, but I'm happy to clean up
my own.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---
 kernel/module.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 1a9a3986b13..f6e08b7cff7 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1673,8 +1673,7 @@ static void layout_sections(struct module *mod,
 			if ((s->sh_flags & masks[m][0]) != masks[m][0]
 			    || (s->sh_flags & masks[m][1])
 			    || s->sh_entsize != ~0UL
-			    || strncmp(secstrings + s->sh_name,
-				       ".init", 5) == 0)
+			    || strstarts(secstrings + s->sh_name, ".init"))
 				continue;
 			s->sh_entsize = get_offset(mod, &mod->core_size, s, i);
 			DEBUGP("\t%s\n", secstrings + s->sh_name);
@@ -1691,8 +1690,7 @@ static void layout_sections(struct module *mod,
 			if ((s->sh_flags & masks[m][0]) != masks[m][0]
 			    || (s->sh_flags & masks[m][1])
 			    || s->sh_entsize != ~0UL
-			    || strncmp(secstrings + s->sh_name,
-				       ".init", 5) != 0)
+			    || !strstarts(secstrings + s->sh_name, ".init"))
 				continue;
 			s->sh_entsize = (get_offset(mod, &mod->init_size, s, i)
 					 | INIT_OFFSET_MASK);
@@ -1825,8 +1823,7 @@ static char elf_type(const Elf_Sym *sym,
 		else
 			return 'b';
 	}
-	if (strncmp(secstrings + sechdrs[sym->st_shndx].sh_name,
-		    ".debug", strlen(".debug")) == 0)
+	if (strstarts(secstrings + sechdrs[sym->st_shndx].sh_name, ".debug"))
 		return 'n';
 	return '?';
 }
@@ -1952,7 +1949,7 @@ static noinline struct module *load_module(void __user *umod,
 		}
 #ifndef CONFIG_MODULE_UNLOAD
 		/* Don't load .exit sections */
-		if (strncmp(secstrings+sechdrs[i].sh_name, ".exit", 5) == 0)
+		if (strstarts(secstrings+sechdrs[i].sh_name, ".exit"))
 			sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC;
 #endif
 		/* Don't keep __versions around; it's just for loading. */
-- 
cgit v1.2.3