X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=kernel%2Fmodule.c;h=1016b75b026ab61b7ef0ee233915c3b1adeaf64d;hb=8213466596bf10b75887754773ee13c10cf86f5c;hp=5842a71cf0527163c960cc8c41d549a5033e3443;hpb=35dead4235e2b67da7275b4122fed37099c2f462;p=safe%2Fjmp%2Flinux-2.6 diff --git a/kernel/module.c b/kernel/module.c index 5842a71..1016b75 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -370,204 +370,98 @@ EXPORT_SYMBOL_GPL(find_module); #ifdef CONFIG_SMP -#ifndef CONFIG_HAVE_LEGACY_PER_CPU_AREA - -static void *percpu_modalloc(unsigned long size, unsigned long align, - const char *name) +static inline void __percpu *mod_percpu(struct module *mod) { - void *ptr; + return mod->percpu; +} +static int percpu_modalloc(struct module *mod, + unsigned long size, unsigned long align) +{ if (align > PAGE_SIZE) { printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n", - name, align, PAGE_SIZE); + mod->name, align, PAGE_SIZE); align = PAGE_SIZE; } - ptr = __alloc_reserved_percpu(size, align); - if (!ptr) + mod->percpu = __alloc_reserved_percpu(size, align); + if (!mod->percpu) { printk(KERN_WARNING "Could not allocate %lu bytes percpu data\n", size); - return ptr; -} - -static void percpu_modfree(void *freeme) -{ - free_percpu(freeme); -} - -#else /* ... CONFIG_HAVE_LEGACY_PER_CPU_AREA */ - -/* Number of blocks used and allocated. */ -static unsigned int pcpu_num_used, pcpu_num_allocated; -/* Size of each block. -ve means used. */ -static int *pcpu_size; - -static int split_block(unsigned int i, unsigned short size) -{ - /* Reallocation required? */ - if (pcpu_num_used + 1 > pcpu_num_allocated) { - int *new; - - new = krealloc(pcpu_size, sizeof(new[0])*pcpu_num_allocated*2, - GFP_KERNEL); - if (!new) - return 0; - - pcpu_num_allocated *= 2; - pcpu_size = new; + return -ENOMEM; } - - /* Insert a new subblock */ - memmove(&pcpu_size[i+1], &pcpu_size[i], - sizeof(pcpu_size[0]) * (pcpu_num_used - i)); - pcpu_num_used++; - - pcpu_size[i+1] -= size; - pcpu_size[i] = size; - return 1; + mod->percpu_size = size; + return 0; } -static inline unsigned int block_size(int val) +static void percpu_modfree(struct module *mod) { - if (val < 0) - return -val; - return val; + free_percpu(mod->percpu); } -static void *percpu_modalloc(unsigned long size, unsigned long align, - const char *name) +static unsigned int find_pcpusec(Elf_Ehdr *hdr, + Elf_Shdr *sechdrs, + const char *secstrings) { - unsigned long extra; - unsigned int i; - void *ptr; - int cpu; - - if (align > PAGE_SIZE) { - printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n", - name, align, PAGE_SIZE); - align = PAGE_SIZE; - } - - ptr = __per_cpu_start; - for (i = 0; i < pcpu_num_used; ptr += block_size(pcpu_size[i]), i++) { - /* Extra for alignment requirement. */ - extra = ALIGN((unsigned long)ptr, align) - (unsigned long)ptr; - BUG_ON(i == 0 && extra != 0); - - if (pcpu_size[i] < 0 || pcpu_size[i] < extra + size) - continue; - - /* Transfer extra to previous block. */ - if (pcpu_size[i-1] < 0) - pcpu_size[i-1] -= extra; - else - pcpu_size[i-1] += extra; - pcpu_size[i] -= extra; - ptr += extra; - - /* Split block if warranted */ - if (pcpu_size[i] - size > sizeof(unsigned long)) - if (!split_block(i, size)) - return NULL; - - /* add the per-cpu scanning areas */ - for_each_possible_cpu(cpu) - kmemleak_alloc(ptr + per_cpu_offset(cpu), size, 0, - GFP_KERNEL); - - /* Mark allocated */ - pcpu_size[i] = -pcpu_size[i]; - return ptr; - } - - printk(KERN_WARNING "Could not allocate %lu bytes percpu data\n", - size); - return NULL; + return find_sec(hdr, sechdrs, secstrings, ".data.percpu"); } -static void percpu_modfree(void *freeme) +static void percpu_modcopy(struct module *mod, + const void *from, unsigned long size) { - unsigned int i; - void *ptr = __per_cpu_start + block_size(pcpu_size[0]); int cpu; - /* First entry is core kernel percpu data. */ - for (i = 1; i < pcpu_num_used; ptr += block_size(pcpu_size[i]), i++) { - if (ptr == freeme) { - pcpu_size[i] = -pcpu_size[i]; - goto free; - } - } - BUG(); - - free: - /* remove the per-cpu scanning areas */ for_each_possible_cpu(cpu) - kmemleak_free(freeme + per_cpu_offset(cpu)); - - /* Merge with previous? */ - if (pcpu_size[i-1] >= 0) { - pcpu_size[i-1] += pcpu_size[i]; - pcpu_num_used--; - memmove(&pcpu_size[i], &pcpu_size[i+1], - (pcpu_num_used - i) * sizeof(pcpu_size[0])); - i--; - } - /* Merge with next? */ - if (i+1 < pcpu_num_used && pcpu_size[i+1] >= 0) { - pcpu_size[i] += pcpu_size[i+1]; - pcpu_num_used--; - memmove(&pcpu_size[i+1], &pcpu_size[i+2], - (pcpu_num_used - (i+1)) * sizeof(pcpu_size[0])); - } + memcpy(per_cpu_ptr(mod->percpu, cpu), from, size); } -static int percpu_modinit(void) +/** + * is_module_percpu_address - test whether address is from module static percpu + * @addr: address to test + * + * Test whether @addr belongs to module static percpu area. + * + * RETURNS: + * %true if @addr is from module static percpu area + */ +bool is_module_percpu_address(unsigned long addr) { - pcpu_num_used = 2; - pcpu_num_allocated = 2; - pcpu_size = kmalloc(sizeof(pcpu_size[0]) * pcpu_num_allocated, - GFP_KERNEL); - /* Static in-kernel percpu data (used). */ - pcpu_size[0] = -(__per_cpu_end-__per_cpu_start); - /* Free room. */ - pcpu_size[1] = PERCPU_ENOUGH_ROOM + pcpu_size[0]; - if (pcpu_size[1] < 0) { - printk(KERN_ERR "No per-cpu room for modules.\n"); - pcpu_num_used = 1; - } - - return 0; -} -__initcall(percpu_modinit); + struct module *mod; + unsigned int cpu; -#endif /* CONFIG_HAVE_LEGACY_PER_CPU_AREA */ + preempt_disable(); -static unsigned int find_pcpusec(Elf_Ehdr *hdr, - Elf_Shdr *sechdrs, - const char *secstrings) -{ - return find_sec(hdr, sechdrs, secstrings, ".data.percpu"); -} + list_for_each_entry_rcu(mod, &modules, list) { + if (!mod->percpu_size) + continue; + for_each_possible_cpu(cpu) { + void *start = per_cpu_ptr(mod->percpu, cpu); -static void percpu_modcopy(void *pcpudest, const void *from, unsigned long size) -{ - int cpu; + if ((void *)addr >= start && + (void *)addr < start + mod->percpu_size) { + preempt_enable(); + return true; + } + } + } - for_each_possible_cpu(cpu) - memcpy(pcpudest + per_cpu_offset(cpu), from, size); + preempt_enable(); + return false; } #else /* ... !CONFIG_SMP */ -static inline void *percpu_modalloc(unsigned long size, unsigned long align, - const char *name) +static inline void __percpu *mod_percpu(struct module *mod) { return NULL; } -static inline void percpu_modfree(void *pcpuptr) +static inline int percpu_modalloc(struct module *mod, + unsigned long size, unsigned long align) +{ + return -ENOMEM; +} +static inline void percpu_modfree(struct module *mod) { - BUG(); } static inline unsigned int find_pcpusec(Elf_Ehdr *hdr, Elf_Shdr *sechdrs, @@ -575,12 +469,16 @@ static inline unsigned int find_pcpusec(Elf_Ehdr *hdr, { return 0; } -static inline void percpu_modcopy(void *pcpudst, const void *src, - unsigned long size) +static inline void percpu_modcopy(struct module *mod, + const void *from, unsigned long size) { /* pcpusec should be 0, and size of that section should be 0. */ BUG_ON(size != 0); } +bool is_module_percpu_address(unsigned long addr) +{ + return false; +} #endif /* CONFIG_SMP */ @@ -623,10 +521,13 @@ static void module_unload_init(struct module *mod) int cpu; INIT_LIST_HEAD(&mod->modules_which_use_me); - for_each_possible_cpu(cpu) - local_set(__module_ref_addr(mod, cpu), 0); + for_each_possible_cpu(cpu) { + per_cpu_ptr(mod->refptr, cpu)->incs = 0; + per_cpu_ptr(mod->refptr, cpu)->decs = 0; + } + /* Hold reference count during initialization. */ - local_set(__module_ref_addr(mod, raw_smp_processor_id()), 1); + __this_cpu_write(mod->refptr->incs, 1); /* Backwards compatibility macros put refcount during init. */ mod->waiter = current; } @@ -765,12 +666,28 @@ static int try_stop_module(struct module *mod, int flags, int *forced) unsigned int module_refcount(struct module *mod) { - unsigned int total = 0; + unsigned int incs = 0, decs = 0; int cpu; for_each_possible_cpu(cpu) - total += local_read(__module_ref_addr(mod, cpu)); - return total; + decs += per_cpu_ptr(mod->refptr, cpu)->decs; + /* + * ensure the incs are added up after the decs. + * module_put ensures incs are visible before decs with smp_wmb. + * + * This 2-count scheme avoids the situation where the refcount + * for CPU0 is read, then CPU0 increments the module refcount, + * then CPU1 drops that refcount, then the refcount for CPU1 is + * read. We would record a decrement but not its corresponding + * increment so we would see a low count (disaster). + * + * Rare situation? But module_refcount can be preempted, and we + * might be tallying up 4096+ CPUs. So it is not impossible. + */ + smp_rmb(); + for_each_possible_cpu(cpu) + incs += per_cpu_ptr(mod->refptr, cpu)->incs; + return incs - decs; } EXPORT_SYMBOL(module_refcount); @@ -946,14 +863,16 @@ static struct module_attribute refcnt = { void module_put(struct module *module) { if (module) { - unsigned int cpu = get_cpu(); - local_dec(__module_ref_addr(module, cpu)); + preempt_disable(); + smp_wmb(); /* see comment in module_refcount */ + __this_cpu_inc(module->refptr->decs); + trace_module_put(module, _RET_IP_, - local_read(__module_ref_addr(module, cpu))); + __this_cpu_read(module->refptr->decs)); /* Maybe they're waiting for us to drop reference? */ if (unlikely(!module_is_live(module))) wake_up_process(module->waiter); - put_cpu(); + preempt_enable(); } } EXPORT_SYMBOL(module_put); @@ -1030,11 +949,23 @@ static int try_to_force_load(struct module *mod, const char *reason) } #ifdef CONFIG_MODVERSIONS +/* If the arch applies (non-zero) relocations to kernel kcrctab, unapply it. */ +static unsigned long maybe_relocated(unsigned long crc, + const struct module *crc_owner) +{ +#ifdef ARCH_RELOCATES_KCRCTAB + if (crc_owner == NULL) + return crc - (unsigned long)reloc_start; +#endif + return crc; +} + static int check_version(Elf_Shdr *sechdrs, unsigned int versindex, const char *symname, struct module *mod, - const unsigned long *crc) + const unsigned long *crc, + const struct module *crc_owner) { unsigned int i, num_versions; struct modversion_info *versions; @@ -1055,10 +986,10 @@ static int check_version(Elf_Shdr *sechdrs, if (strcmp(versions[i].name, symname) != 0) continue; - if (versions[i].crc == *crc) + if (versions[i].crc == maybe_relocated(*crc, crc_owner)) return 1; DEBUGP("Found checksum %lX vs module %lX\n", - *crc, versions[i].crc); + maybe_relocated(*crc, crc_owner), versions[i].crc); goto bad_version; } @@ -1081,7 +1012,8 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs, if (!find_symbol(MODULE_SYMBOL_PREFIX "module_layout", NULL, &crc, true, false)) BUG(); - return check_version(sechdrs, versindex, "module_layout", mod, crc); + return check_version(sechdrs, versindex, "module_layout", mod, crc, + NULL); } /* First part is kernel version, which we ignore if module has crcs. */ @@ -1099,7 +1031,8 @@ static inline int check_version(Elf_Shdr *sechdrs, unsigned int versindex, const char *symname, struct module *mod, - const unsigned long *crc) + const unsigned long *crc, + const struct module *crc_owner) { return 1; } @@ -1134,8 +1067,8 @@ static const struct kernel_symbol *resolve_symbol(Elf_Shdr *sechdrs, /* 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)) + if (!check_version(sechdrs, versindex, name, mod, crc, owner) + || !use_module(mod, owner)) sym = NULL; } return sym; @@ -1146,6 +1079,12 @@ static const struct kernel_symbol *resolve_symbol(Elf_Shdr *sechdrs, * J. Corbet */ #if defined(CONFIG_KALLSYMS) && defined(CONFIG_SYSFS) + +static inline bool sect_empty(const Elf_Shdr *sect) +{ + return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0; +} + struct module_sect_attr { struct module_attribute mattr; @@ -1187,8 +1126,7 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect, /* Count loaded sections and allocate structures */ for (i = 0; i < nsect; i++) - if (sechdrs[i].sh_flags & SHF_ALLOC - && sechdrs[i].sh_size) + if (!sect_empty(&sechdrs[i])) nloaded++; size[0] = ALIGN(sizeof(*sect_attrs) + nloaded * sizeof(sect_attrs->attrs[0]), @@ -1206,9 +1144,7 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect, sattr = §_attrs->attrs[0]; gattr = §_attrs->grp.attrs[0]; for (i = 0; i < nsect; i++) { - if (! (sechdrs[i].sh_flags & SHF_ALLOC)) - continue; - if (!sechdrs[i].sh_size) + if (sect_empty(&sechdrs[i])) continue; sattr->address = sechdrs[i].sh_addr; sattr->name = kstrdup(secstrings + sechdrs[i].sh_name, @@ -1216,6 +1152,7 @@ static void add_sect_attrs(struct module *mod, unsigned int nsect, if (sattr->name == NULL) goto out; sect_attrs->nsections++; + sysfs_attr_init(&sattr->mattr.attr); sattr->mattr.show = module_sect_show; sattr->mattr.store = NULL; sattr->mattr.attr.name = sattr->name; @@ -1292,7 +1229,7 @@ static void add_notes_attrs(struct module *mod, unsigned int nsect, /* Count notes sections and allocate structures. */ notes = 0; for (i = 0; i < nsect; i++) - if ((sechdrs[i].sh_flags & SHF_ALLOC) && + if (!sect_empty(&sechdrs[i]) && (sechdrs[i].sh_type == SHT_NOTE)) ++notes; @@ -1308,9 +1245,10 @@ static void add_notes_attrs(struct module *mod, unsigned int nsect, notes_attrs->notes = notes; nattr = ¬es_attrs->attrs[0]; for (loaded = i = 0; i < nsect; ++i) { - if (!(sechdrs[i].sh_flags & SHF_ALLOC)) + if (sect_empty(&sechdrs[i])) continue; if (sechdrs[i].sh_type == SHT_NOTE) { + sysfs_bin_attr_init(nattr); nattr->attr.name = mod->sect_attrs->attrs[loaded].name; nattr->attr.mode = S_IRUGO; nattr->size = sechdrs[i].sh_size; @@ -1383,6 +1321,7 @@ int module_add_modinfo_attrs(struct module *mod) if (!attr->test || (attr->test && attr->test(mod))) { memcpy(temp_attr, attr, sizeof(*temp_attr)); + sysfs_attr_init(&temp_attr->attr); error = sysfs_create_file(&mod->mkobj.kobj,&temp_attr->attr); ++temp_attr; } @@ -1528,11 +1467,10 @@ static void free_module(struct module *mod) /* This may be NULL, but that's OK */ module_free(mod, mod->module_init); kfree(mod->args); - if (mod->percpu) - percpu_modfree(mod->percpu); -#if defined(CONFIG_MODULE_UNLOAD) && defined(CONFIG_SMP) + percpu_modfree(mod); +#if defined(CONFIG_MODULE_UNLOAD) if (mod->refptr) - percpu_modfree(mod->refptr); + free_percpu(mod->refptr); #endif /* Free lock-classes: */ lockdep_free_key_range(mod->module_core, mod->core_size); @@ -1648,7 +1586,7 @@ static int simplify_symbols(Elf_Shdr *sechdrs, default: /* Divert to percpu allocation if a percpu var. */ if (sym[i].st_shndx == pcpuindex) - secbase = (unsigned long)mod->percpu; + secbase = (unsigned long)mod_percpu(mod); else secbase = sechdrs[sym[i].st_shndx].sh_addr; sym[i].st_value += secbase; @@ -2046,9 +1984,7 @@ static void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr, unsigned int i; /* only scan the sections containing data */ - kmemleak_scan_area(mod->module_core, (unsigned long)mod - - (unsigned long)mod->module_core, - sizeof(struct module), GFP_KERNEL); + kmemleak_scan_area(mod, sizeof(struct module), GFP_KERNEL); for (i = 1; i < hdr->e_shnum; i++) { if (!(sechdrs[i].sh_flags & SHF_ALLOC)) @@ -2057,8 +1993,7 @@ static void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr, && strncmp(secstrings + sechdrs[i].sh_name, ".bss", 4) != 0) continue; - kmemleak_scan_area(mod->module_core, sechdrs[i].sh_addr - - (unsigned long)mod->module_core, + kmemleak_scan_area((void *)sechdrs[i].sh_addr, sechdrs[i].sh_size, GFP_KERNEL); } } @@ -2085,7 +2020,7 @@ static noinline struct module *load_module(void __user *umod, unsigned int modindex, versindex, infoindex, pcpuindex; struct module *mod; long err = 0; - void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */ + void *ptr = NULL; /* Stops spurious gcc warning */ unsigned long symoffs, stroffs, *strmap; mm_segment_t old_fs; @@ -2225,15 +2160,11 @@ static noinline struct module *load_module(void __user *umod, if (pcpuindex) { /* We have a special allocation for this section. */ - percpu = percpu_modalloc(sechdrs[pcpuindex].sh_size, - sechdrs[pcpuindex].sh_addralign, - mod->name); - if (!percpu) { - err = -ENOMEM; + err = percpu_modalloc(mod, sechdrs[pcpuindex].sh_size, + sechdrs[pcpuindex].sh_addralign); + if (err) goto free_mod; - } sechdrs[pcpuindex].sh_flags &= ~(unsigned long)SHF_ALLOC; - mod->percpu = percpu; } /* Determine total sizes, and put offsets in sh_entsize. For now @@ -2298,9 +2229,8 @@ static noinline struct module *load_module(void __user *umod, mod = (void *)sechdrs[modindex].sh_addr; kmemleak_load_module(mod, hdr, sechdrs, secstrings); -#if defined(CONFIG_MODULE_UNLOAD) && defined(CONFIG_SMP) - mod->refptr = percpu_modalloc(sizeof(local_t), __alignof__(local_t), - mod->name); +#if defined(CONFIG_MODULE_UNLOAD) + mod->refptr = alloc_percpu(struct module_ref); if (!mod->refptr) { err = -ENOMEM; goto free_init; @@ -2386,6 +2316,12 @@ static noinline struct module *load_module(void __user *umod, "_ftrace_events", sizeof(*mod->trace_events), &mod->num_trace_events); + /* + * This section contains pointers to allocated objects in the trace + * code and not scanning it leads to false positives. + */ + kmemleak_scan_area(mod->trace_events, sizeof(*mod->trace_events) * + mod->num_trace_events, GFP_KERNEL); #endif #ifdef CONFIG_FTRACE_MCOUNT_RECORD /* sechdrs[0].sh_size is always zero */ @@ -2443,7 +2379,7 @@ static noinline struct module *load_module(void __user *umod, sort_extable(mod->extable, mod->extable + mod->num_exentries); /* Finally, copy percpu area over. */ - percpu_modcopy(mod->percpu, (void *)sechdrs[pcpuindex].sh_addr, + percpu_modcopy(mod, (void *)sechdrs[pcpuindex].sh_addr, sechdrs[pcpuindex].sh_size); add_kallsyms(mod, sechdrs, hdr->e_shnum, symindex, strindex, @@ -2526,8 +2462,8 @@ static noinline struct module *load_module(void __user *umod, kobject_put(&mod->mkobj.kobj); free_unload: module_unload_free(mod); -#if defined(CONFIG_MODULE_UNLOAD) && defined(CONFIG_SMP) - percpu_modfree(mod->refptr); +#if defined(CONFIG_MODULE_UNLOAD) + free_percpu(mod->refptr); free_init: #endif module_free(mod, mod->module_init); @@ -2535,8 +2471,7 @@ static noinline struct module *load_module(void __user *umod, module_free(mod, mod->module_core); /* mod will be freed with core. Don't access it beyond this line! */ free_percpu: - if (percpu) - percpu_modfree(percpu); + percpu_modfree(mod); free_mod: kfree(args); kfree(strmap);