From a58730c42174672fe0012a4edbe3e38f94ef2bad Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 13 Mar 2008 09:03:44 +0000 Subject: [PATCH 1/6] module: make module_sect_attrs private to kernel/module.c No-one else is using these afaics. Signed-off-by: Jan Beulich Signed-off-by: Rusty Russell --- include/linux/module.h | 17 ----------------- kernel/module.c | 16 +++++++++++++++- 2 files changed, 15 insertions(+), 18 deletions(-) diff --git a/include/linux/module.h b/include/linux/module.h index 819c4e889bf1..a29c2ebb7c38 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -229,23 +229,6 @@ enum module_state MODULE_STATE_GOING, }; -/* Similar stuff for section attributes. */ -struct module_sect_attr -{ - struct module_attribute mattr; - char *name; - unsigned long address; -}; - -struct module_sect_attrs -{ - struct attribute_group grp; - int nsections; - struct module_sect_attr attrs[0]; -}; - -struct module_param_attrs; - struct module { enum module_state state; diff --git a/kernel/module.c b/kernel/module.c index 8d6cccc6c3cf..b0d7c2a41bd9 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -991,6 +991,20 @@ static unsigned long resolve_symbol(Elf_Shdr *sechdrs, * J. Corbet */ #if defined(CONFIG_KALLSYMS) && defined(CONFIG_SYSFS) +struct module_sect_attr +{ + struct module_attribute mattr; + char *name; + unsigned long address; +}; + +struct module_sect_attrs +{ + struct attribute_group grp; + unsigned int nsections; + struct module_sect_attr attrs[0]; +}; + static ssize_t module_sect_show(struct module_attribute *mattr, struct module *mod, char *buf) { @@ -1001,7 +1015,7 @@ static ssize_t module_sect_show(struct module_attribute *mattr, static void free_sect_attrs(struct module_sect_attrs *sect_attrs) { - int section; + unsigned int section; for (section = 0; section < sect_attrs->nsections; section++) kfree(sect_attrs->attrs[section].name); From ea01e798e2d27fd04142e0473ca36570fa9d9218 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 13 Mar 2008 09:02:17 +0000 Subject: [PATCH 2/6] module: reduce module image and resident size Resulting reduction (x86-64, gcc 4.1.2) with my (special purpose, i.e. much reduced) configurations: - 16k kernel resident size - 180k module resident size - 10k module image size Signed-off-by: Jan Beulich Signed-off-by: Rusty Russell --- include/linux/module.h | 2 +- kernel/module.c | 3 ++- 2 files changed, 3 insertions(+), 2 deletions(-) diff --git a/include/linux/module.h b/include/linux/module.h index a29c2ebb7c38..3e03b1acbc94 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -190,7 +190,7 @@ void *__symbol_get_gpl(const char *symbol); extern typeof(sym) sym; \ __CRC_SYMBOL(sym, sec) \ static const char __kstrtab_##sym[] \ - __attribute__((section("__ksymtab_strings"))) \ + __attribute__((section("__ksymtab_strings"), aligned(1))) \ = MODULE_SYMBOL_PREFIX #sym; \ static const struct kernel_symbol __ksymtab_##sym \ __used \ diff --git a/kernel/module.c b/kernel/module.c index b0d7c2a41bd9..031bf26af8ea 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1828,8 +1828,9 @@ static struct module *load_module(void __user *umod, unwindex = find_sec(hdr, sechdrs, secstrings, ARCH_UNWIND_SECTION_NAME); #endif - /* Don't keep modinfo section */ + /* Don't keep modinfo and version sections. */ sechdrs[infoindex].sh_flags &= ~(unsigned long)SHF_ALLOC; + sechdrs[versindex].sh_flags &= ~(unsigned long)SHF_ALLOC; #ifdef CONFIG_KALLSYMS /* Keep symbol and string tables for decoding later. */ sechdrs[symindex].sh_flags |= SHF_ALLOC; From ad9546c9917d44eddc7676b639296d624cee455e Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 1 May 2008 21:14:59 -0500 Subject: [PATCH 3/6] module: neaten __find_symbol, rename to find_symbol __find_symbol() has grown over time: there are now 5 different arrays of symbols it traverses. It also shouldn't print out a warning on some calls (ie. verify_symbol which simply checks for name clashes, and __symbol_put which checks for bugs). 1) Rename to find_symbol: no need for underscores. 2) Use bool and add "warn" parameter to suppress warnings. 3) Make table-driven rather than open coded. Signed-off-by: Rusty Russell --- kernel/module.c | 246 ++++++++++++++++++++++++------------------------ 1 file changed, 125 insertions(+), 121 deletions(-) diff --git a/kernel/module.c b/kernel/module.c index 031bf26af8ea..679e4c88ed9e 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -164,131 +164,140 @@ static const struct kernel_symbol *lookup_symbol(const char *name, return NULL; } -static void printk_unused_warning(const char *name) +static bool always_ok(bool gplok, bool warn, const char *name) { - printk(KERN_WARNING "Symbol %s is marked as UNUSED, " - "however this module is using it.\n", name); - printk(KERN_WARNING "This symbol will go away in the future.\n"); - printk(KERN_WARNING "Please evalute if this is the right api to use, " - "and if it really is, submit a report the linux kernel " - "mailinglist together with submitting your code for " - "inclusion.\n"); + return true; } -/* Find a symbol, return value, crc and module which owns it */ -static unsigned long __find_symbol(const char *name, - struct module **owner, - const unsigned long **crc, - int gplok) +static bool printk_unused_warning(bool gplok, bool warn, const char *name) +{ + if (warn) { + printk(KERN_WARNING "Symbol %s is marked as UNUSED, " + "however this module is using it.\n", name); + printk(KERN_WARNING + "This symbol will go away in the future.\n"); + printk(KERN_WARNING + "Please evalute if this is the right api to use and if " + "it really is, submit a report the linux kernel " + "mailinglist together with submitting your code for " + "inclusion.\n"); + } + return true; +} + +static bool gpl_only_unused_warning(bool gplok, bool warn, const char *name) +{ + if (!gplok) + return false; + return printk_unused_warning(gplok, warn, name); +} + +static bool gpl_only(bool gplok, bool warn, const char *name) +{ + return gplok; +} + +static bool warn_if_not_gpl(bool gplok, bool warn, const char *name) +{ + if (!gplok && warn) { + printk(KERN_WARNING "Symbol %s is being used " + "by a non-GPL module, which will not " + "be allowed in the future\n", name); + printk(KERN_WARNING "Please see the file " + "Documentation/feature-removal-schedule.txt " + "in the kernel source tree for more details.\n"); + } + return true; +} + +struct symsearch { + const struct kernel_symbol *start, *stop; + const unsigned long *crcs; + bool (*check)(bool gplok, bool warn, const char *name); +}; + +/* Look through this array of symbol tables for a symbol match which + * passes the check function. */ +static const struct kernel_symbol *search_symarrays(const struct symsearch *arr, + unsigned int num, + const char *name, + bool gplok, + bool warn, + const unsigned long **crc) +{ + unsigned int i; + const struct kernel_symbol *ks; + + for (i = 0; i < num; i++) { + ks = lookup_symbol(name, arr[i].start, arr[i].stop); + if (!ks || !arr[i].check(gplok, warn, name)) + continue; + + if (crc) + *crc = symversion(arr[i].crcs, ks - arr[i].start); + return ks; + } + return NULL; +} + +/* 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) { struct module *mod; const struct kernel_symbol *ks; + const struct symsearch arr[] = { + { __start___ksymtab, __stop___ksymtab, __start___kcrctab, + always_ok }, + { __start___ksymtab_gpl, __stop___ksymtab_gpl, + __start___kcrctab_gpl, gpl_only }, + { __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future, + __start___kcrctab_gpl_future, warn_if_not_gpl }, + { __start___ksymtab_unused, __stop___ksymtab_unused, + __start___kcrctab_unused, printk_unused_warning }, + { __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl, + __start___kcrctab_unused_gpl, gpl_only_unused_warning }, + }; /* Core kernel first. */ - *owner = NULL; - ks = lookup_symbol(name, __start___ksymtab, __stop___ksymtab); + ks = search_symarrays(arr, ARRAY_SIZE(arr), name, gplok, warn, crc); if (ks) { - *crc = symversion(__start___kcrctab, (ks - __start___ksymtab)); - return ks->value; - } - if (gplok) { - ks = lookup_symbol(name, __start___ksymtab_gpl, - __stop___ksymtab_gpl); - if (ks) { - *crc = symversion(__start___kcrctab_gpl, - (ks - __start___ksymtab_gpl)); - return ks->value; - } - } - ks = lookup_symbol(name, __start___ksymtab_gpl_future, - __stop___ksymtab_gpl_future); - if (ks) { - if (!gplok) { - printk(KERN_WARNING "Symbol %s is being used " - "by a non-GPL module, which will not " - "be allowed in the future\n", name); - printk(KERN_WARNING "Please see the file " - "Documentation/feature-removal-schedule.txt " - "in the kernel source tree for more " - "details.\n"); - } - *crc = symversion(__start___kcrctab_gpl_future, - (ks - __start___ksymtab_gpl_future)); - return ks->value; - } - - ks = lookup_symbol(name, __start___ksymtab_unused, - __stop___ksymtab_unused); - if (ks) { - printk_unused_warning(name); - *crc = symversion(__start___kcrctab_unused, - (ks - __start___ksymtab_unused)); - return ks->value; - } - - if (gplok) - ks = lookup_symbol(name, __start___ksymtab_unused_gpl, - __stop___ksymtab_unused_gpl); - if (ks) { - printk_unused_warning(name); - *crc = symversion(__start___kcrctab_unused_gpl, - (ks - __start___ksymtab_unused_gpl)); + if (owner) + *owner = NULL; return ks->value; } /* Now try modules. */ list_for_each_entry(mod, &modules, list) { - *owner = mod; - ks = lookup_symbol(name, mod->syms, mod->syms + mod->num_syms); - if (ks) { - *crc = symversion(mod->crcs, (ks - mod->syms)); - return ks->value; - } + struct symsearch arr[] = { + { mod->syms, mod->syms + mod->num_syms, mod->crcs, + always_ok }, + { mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms, + mod->gpl_crcs, gpl_only }, + { mod->gpl_future_syms, + mod->gpl_future_syms + mod->num_gpl_future_syms, + mod->gpl_future_crcs, warn_if_not_gpl }, + { mod->unused_syms, + mod->unused_syms + mod->num_unused_syms, + mod->unused_crcs, printk_unused_warning }, + { mod->unused_gpl_syms, + mod->unused_gpl_syms + mod->num_unused_gpl_syms, + mod->unused_gpl_crcs, gpl_only_unused_warning }, + }; - if (gplok) { - ks = lookup_symbol(name, mod->gpl_syms, - mod->gpl_syms + mod->num_gpl_syms); - if (ks) { - *crc = symversion(mod->gpl_crcs, - (ks - mod->gpl_syms)); - return ks->value; - } - } - ks = lookup_symbol(name, mod->unused_syms, mod->unused_syms + mod->num_unused_syms); + ks = search_symarrays(arr, ARRAY_SIZE(arr), + name, gplok, warn, crc); if (ks) { - printk_unused_warning(name); - *crc = symversion(mod->unused_crcs, (ks - mod->unused_syms)); - return ks->value; - } - - if (gplok) { - ks = lookup_symbol(name, mod->unused_gpl_syms, - mod->unused_gpl_syms + mod->num_unused_gpl_syms); - if (ks) { - printk_unused_warning(name); - *crc = symversion(mod->unused_gpl_crcs, - (ks - mod->unused_gpl_syms)); - return ks->value; - } - } - ks = lookup_symbol(name, mod->gpl_future_syms, - (mod->gpl_future_syms + - mod->num_gpl_future_syms)); - if (ks) { - if (!gplok) { - printk(KERN_WARNING "Symbol %s is being used " - "by a non-GPL module, which will not " - "be allowed in the future\n", name); - printk(KERN_WARNING "Please see the file " - "Documentation/feature-removal-schedule.txt " - "in the kernel source tree for more " - "details.\n"); - } - *crc = symversion(mod->gpl_future_crcs, - (ks - mod->gpl_future_syms)); + if (owner) + *owner = mod; return ks->value; } } + DEBUGP("Failed to find symbol %s\n", name); return -ENOENT; } @@ -777,10 +786,9 @@ static void print_unload_info(struct seq_file *m, struct module *mod) void __symbol_put(const char *symbol) { struct module *owner; - const unsigned long *crc; preempt_disable(); - if (IS_ERR_VALUE(__find_symbol(symbol, &owner, &crc, 1))) + if (IS_ERR_VALUE(find_symbol(symbol, &owner, NULL, true, false))) BUG(); module_put(owner); preempt_enable(); @@ -924,13 +932,10 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs, struct module *mod) { const unsigned long *crc; - struct module *owner; - if (IS_ERR_VALUE(__find_symbol("struct_module", - &owner, &crc, 1))) + if (IS_ERR_VALUE(find_symbol("struct_module", NULL, &crc, true, false))) BUG(); - return check_version(sechdrs, versindex, "struct_module", mod, - crc); + return check_version(sechdrs, versindex, "struct_module", mod, crc); } /* First part is kernel version, which we ignore. */ @@ -974,8 +979,8 @@ static unsigned long resolve_symbol(Elf_Shdr *sechdrs, unsigned long ret; const unsigned long *crc; - ret = __find_symbol(name, &owner, &crc, - !(mod->taints & TAINT_PROPRIETARY_MODULE)); + ret = find_symbol(name, &owner, &crc, + !(mod->taints & TAINT_PROPRIETARY_MODULE), true); if (!IS_ERR_VALUE(ret)) { /* use_module can fail due to OOM, or module initialization or unloading */ @@ -1376,10 +1381,9 @@ void *__symbol_get(const char *symbol) { struct module *owner; unsigned long value; - const unsigned long *crc; preempt_disable(); - value = __find_symbol(symbol, &owner, &crc, 1); + value = find_symbol(symbol, &owner, NULL, true, true); if (IS_ERR_VALUE(value)) value = 0; else if (strong_try_module_get(owner)) @@ -1402,16 +1406,16 @@ static int verify_export_symbols(struct module *mod) const unsigned long *crc; for (i = 0; i < mod->num_syms; i++) - if (!IS_ERR_VALUE(__find_symbol(mod->syms[i].name, - &owner, &crc, 1))) { + if (!IS_ERR_VALUE(find_symbol(mod->syms[i].name, + &owner, &crc, true, false))) { name = mod->syms[i].name; ret = -ENOEXEC; goto dup; } for (i = 0; i < mod->num_gpl_syms; i++) - if (!IS_ERR_VALUE(__find_symbol(mod->gpl_syms[i].name, - &owner, &crc, 1))) { + if (!IS_ERR_VALUE(find_symbol(mod->gpl_syms[i].name, + &owner, &crc, true, false))) { name = mod->gpl_syms[i].name; ret = -ENOEXEC; goto dup; From 4e2d92454b2d822fe1d474efabccc2a3806d5f86 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 1 May 2008 21:15:00 -0500 Subject: [PATCH 4/6] module: set unused_gpl_crcs instead of overwriting unused_crcs Obvious typo, but I don't know of any modules with unused GPL exports, and then it would take someone noticing that the version shouldn't have matched in a dependent module. Signed-off-by: Rusty Russell --- kernel/module.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/module.c b/kernel/module.c index 679e4c88ed9e..ee918938518a 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1996,7 +1996,8 @@ static struct module *load_module(void __user *umod, mod->unused_crcs = (void *)sechdrs[unusedcrcindex].sh_addr; mod->unused_gpl_syms = (void *)sechdrs[unusedgplindex].sh_addr; if (unusedgplcrcindex) - mod->unused_crcs = (void *)sechdrs[unusedgplcrcindex].sh_addr; + mod->unused_gpl_crcs + = (void *)sechdrs[unusedgplcrcindex].sh_addr; #ifdef CONFIG_MODVERSIONS if ((mod->num_syms && !crcindex) || From b211104d111c99dbb97c636b57bd9db711455684 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Thu, 1 May 2008 21:15:00 -0500 Subject: [PATCH 5/6] module: Enhance verify_export_symbols Make verify_export_symbols check the modules unused, unused_gpl and gpl_future syms. Inspired by Jan Beulich's fix, but table-driven. Signed-off-by: Rusty Russell --- kernel/module.c | 48 ++++++++++++++++++++++++------------------------ 1 file changed, 24 insertions(+), 24 deletions(-) diff --git a/kernel/module.c b/kernel/module.c index ee918938518a..d2d093e74165 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -1400,33 +1400,33 @@ EXPORT_SYMBOL_GPL(__symbol_get); */ static int verify_export_symbols(struct module *mod) { - const char *name = NULL; - unsigned long i, ret = 0; + unsigned int i; struct module *owner; - const unsigned long *crc; + const struct kernel_symbol *s; + struct { + const struct kernel_symbol *sym; + unsigned int num; + } arr[] = { + { mod->syms, mod->num_syms }, + { mod->gpl_syms, mod->num_gpl_syms }, + { mod->gpl_future_syms, mod->num_gpl_future_syms }, + { mod->unused_syms, mod->num_unused_syms }, + { mod->unused_gpl_syms, mod->num_unused_gpl_syms }, + }; - for (i = 0; i < mod->num_syms; i++) - if (!IS_ERR_VALUE(find_symbol(mod->syms[i].name, - &owner, &crc, true, false))) { - name = mod->syms[i].name; - ret = -ENOEXEC; - goto dup; + 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))) { + printk(KERN_ERR + "%s: exports duplicate symbol %s" + " (owned by %s)\n", + mod->name, s->name, module_name(owner)); + return -ENOEXEC; + } } - - for (i = 0; i < mod->num_gpl_syms; i++) - if (!IS_ERR_VALUE(find_symbol(mod->gpl_syms[i].name, - &owner, &crc, true, false))) { - name = mod->gpl_syms[i].name; - ret = -ENOEXEC; - goto dup; - } - -dup: - if (ret) - printk(KERN_ERR "%s: exports duplicate symbol %s (owned by %s)\n", - mod->name, name, module_name(owner)); - - return ret; + } + return 0; } /* Change all symbols so that st_value encodes the pointer directly. */ From df4b565e1fbc777bb6e274378a41fa8ff7485680 Mon Sep 17 00:00:00 2001 From: Peter Oberparleiter Date: Mon, 21 Apr 2008 14:34:31 +0200 Subject: [PATCH 6/6] module: add MODULE_STATE_GOING notifier call Provide module unload callback. Required by the gcov profiling infrastructure to keep track of profiling data structures. Signed-off-by: Peter Oberparleiter Signed-off-by: Rusty Russell --- kernel/module.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/kernel/module.c b/kernel/module.c index d2d093e74165..8674a390a2e8 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -745,12 +745,13 @@ sys_delete_module(const char __user *name_user, unsigned int flags) if (!forced && module_refcount(mod) != 0) wait_for_zero_refcount(mod); + mutex_unlock(&module_mutex); /* Final destruction now noone is using it. */ - if (mod->exit != NULL) { - mutex_unlock(&module_mutex); + if (mod->exit != NULL) mod->exit(); - mutex_lock(&module_mutex); - } + blocking_notifier_call_chain(&module_notify_list, + MODULE_STATE_GOING, mod); + mutex_lock(&module_mutex); /* Store the name of the last unloaded module for diagnostic purposes */ strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module)); free_module(mod); @@ -2191,6 +2192,8 @@ sys_init_module(void __user *umod, mod->state = MODULE_STATE_GOING; synchronize_sched(); module_put(mod); + blocking_notifier_call_chain(&module_notify_list, + MODULE_STATE_GOING, mod); mutex_lock(&module_mutex); free_module(mod); mutex_unlock(&module_mutex);