From 3861a17bcc0af815f684c6178bc9ec2d790c350e Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sun, 8 Feb 2009 00:04:02 +0100 Subject: tracing/function-graph-tracer: drop the kernel_text_address check When the function graph tracer picks a return address, it ensures this address is really a kernel text one by calling __kernel_text_address() Actually this path has never been taken.Its role was more likely to debug the tracer on the beginning of its development but this function is wasteful since it is called for every traced function. The fault check is already sufficient. Signed-off-by: Frederic Weisbecker Signed-off-by: Ingo Molnar --- kernel/module.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index ba22484..22d7379 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2735,7 +2735,7 @@ int is_module_address(unsigned long addr) /* Is this a valid kernel address? */ -__notrace_funcgraph struct module *__module_text_address(unsigned long addr) +struct module *__module_text_address(unsigned long addr) { struct module *mod; -- cgit v1.1 From e180a6b7759a99a28cbcce3547c4c80822cb6c2a Mon Sep 17 00:00:00 2001 From: Rusty Russell 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 Diagnosed-by: Frederic Weisbecker Tested-by: Frederic Weisbecker Tested-by: Christof Schmitt Signed-off-by: Rusty Russell --- kernel/module.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index f77ac32..b862fdb 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); -- cgit v1.1 From b10153fe31dde3805f8320b61ef147cebe379aee Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Am=C3=A9rico=20Wang?= 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 Cc: Rusty Russell Signed-off-by: Rusty Russell --- kernel/module.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index b862fdb..7af72bb 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 v1.1 From 414fd31b2553aaf160ca9b9afe45aa0372b01b92 Mon Sep 17 00:00:00 2001 From: Tim Abbott 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 Cc: Jeff Arnold Signed-off-by: Tim Abbott Signed-off-by: Rusty Russell (bugfix and style) --- kernel/module.c | 75 ++++++++++++++++++++++++++++----------------------------- 1 file changed, 37 insertions(+), 38 deletions(-) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index 7af72bb..2f0fddf 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 v1.1 From e610499e2656e61975affd0af56b26eb73964c84 Mon Sep 17 00:00:00 2001 From: Rusty Russell 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 Cc: Jeff Arnold Cc: Tim Abbott Signed-off-by: Rusty Russell --- kernel/module.c | 76 +++++++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 58 insertions(+), 18 deletions(-) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index 2f0fddf..bd15a94 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 v1.1 From a6e6abd575fcbe6572ebc7a70ad616406d206fa8 Mon Sep 17 00:00:00 2001 From: Rusty Russell 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 --- kernel/module.c | 17 ++++------------- 1 file changed, 4 insertions(+), 13 deletions(-) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index bd15a94..8ddca62 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 v1.1 From 75a66614db21007bcc8c37f9c5d5b922981387b9 Mon Sep 17 00:00:00 2001 From: Anders Kaseorg 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 Cc: Tim Abbott Signed-off-by: Anders Kaseorg Signed-off-by: Rusty Russell --- kernel/module.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index 8ddca62..dd4389b 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 v1.1 From c6b37801911d7f4663c99cad8aa230bc934cea82 Mon Sep 17 00:00:00 2001 From: Tim Abbott 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 Cc: Jeff Arnold Signed-off-by: Tim Abbott Signed-off-by: Rusty Russell --- kernel/module.c | 43 +++++++++++++++++++------------------------ 1 file changed, 19 insertions(+), 24 deletions(-) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index dd4389b..5fd0076 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 v1.1 From c6e665c8f0c18ab3686117905765b5139efd6ebd Mon Sep 17 00:00:00 2001 From: Rusty Russell 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: : no version for "magic" found: kernel tainted. New: : bad vermagic: kernel tainted. Old: : no version for "nocrc" found: kernel tainted. New: : no versions for exported symbols: kernel tainted. Old: : no version for "" found: kernel tainted. New: : : kernel tainted. Signed-off-by: Rusty Russell --- kernel/module.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index 5fd0076..599fc85 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 v1.1 From 9cb610d8e35fe3ec95a2fe2030b02f85aeea83c1 Mon Sep 17 00:00:00 2001 From: Rusty Russell 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 Signed-off-by: Rusty Russell --- kernel/module.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index 599fc85..784bf6d 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 v1.1 From 8c8ef42aee8fcfb4128bb94c50d55c9f80ade525 Mon Sep 17 00:00:00 2001 From: Rusty Russell 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 --- kernel/module.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index 784bf6d..e8cf636 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 -- cgit v1.1 From e91defa26c527ceeaff6266c55cdc7e17c9081a2 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 31 Mar 2009 13:05:35 -0600 Subject: module: don't use stop_machine on module load Kay Sievers 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 Signed-off-by: Rusty Russell --- kernel/module.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index e8cf636..1a9a398 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 v1.1 From 49502677e11079c2e3e01867c922a894ce06a8be Mon Sep 17 00:00:00 2001 From: Rusty Russell 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 --- kernel/module.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index 1a9a398..f6e08b7 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 v1.1 From 2e45e77787c9d0720b046eb69856edf43b17e33e Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Tue, 7 Apr 2009 17:12:43 +0930 Subject: Revert "module: remove the SHF_ALLOC flag on the __versions section." This reverts commit 9cb610d8e35fe3ec95a2fe2030b02f85aeea83c1. This was an impressively stupid patch. Firstly, we reset the SHF_ALLOC flag lower down in the same function, so the patch was useless. Even better, find_sec() ignores sections with SHF_ALLOC not set, so it breaks CONFIG_MODVERSIONS=y with CONFIG_MODULE_FORCE_LOAD=n, which refuses to load the module since it can't find the __versions section. Signed-off-by: Rusty Russell --- kernel/module.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index c268a77..05f014e 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1952,9 +1952,6 @@ static noinline struct module *load_module(void __user *umod, 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. */ - if (strcmp(secstrings + sechdrs[i].sh_name, "__versions") == 0) - sechdrs[i].sh_flags &= ~(unsigned long)SHF_ALLOC; } modindex = find_sec(hdr, sechdrs, secstrings, -- cgit v1.1 From d6de2c80e9d758d2e36c21699117db6178c0f517 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Fri, 10 Apr 2009 12:17:41 -0700 Subject: async: Fix module loading async-work regression Several drivers use asynchronous work to do device discovery, and we synchronize with them in the compiled-in case before we actually try to mount root filesystems etc. However, when compiled as modules, that synchronization is missing - the module loading completes, but the driver hasn't actually finished probing for devices, and that means that any user mode that expects to use the devices after the 'insmod' is now potentially broken. We already saw one case of a similar issue in the ACPI battery code, where the kernel itself expected the module to be all done, and unmapped the init memory - but the async device discovery was still running. That got hacked around by just removing the "__init" (see commit 5d38258ec026921a7b266f4047ebeaa75db358e5 "ACPI battery: fix async boot oops"), but the real fix is to just make the module loading wait for all async work to be completed. It will slow down module loading, but since common devices should be built in anyway, and since the bug is really annoying and hard to handle from user space (and caused several S3 resume regressions), the simple fix to wait is the right one. This fixes at least http://bugzilla.kernel.org/show_bug.cgi?id=13063 but probably a few other bugzilla entries too (12936, for example), and is confirmed to fix Rafael's storage driver breakage after resume bug report (no bugzilla entry). We should also be able to now revert that ACPI battery fix. Reported-and-tested-by: Rafael J. Wysocki Tested-by: Heinz Diehl Acked-by: Arjan van de Ven Signed-off-by: Linus Torvalds --- kernel/module.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel/module.c') diff --git a/kernel/module.c b/kernel/module.c index 05f014e..e797812 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -2388,6 +2388,9 @@ SYSCALL_DEFINE3(init_module, void __user *, umod, blocking_notifier_call_chain(&module_notify_list, MODULE_STATE_LIVE, mod); + /* We need to finish all async code before the module init sequence is done */ + async_synchronize_full(); + mutex_lock(&module_mutex); /* Drop initial reference. */ module_put(mod); -- cgit v1.1