Modules updates for v4.13
Summary of modules changes for the 4.13 merge window:
- Minor code cleanups
- Avoid accessing mod struct prior to checking module struct version, from Kees
- Fix racy atomic inc/dec logic of kmod_concurrent_max in kmod, from Luis
Signed-off-by: Jessica Yu <jeyu@kernel.org>
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Merge tag 'modules-for-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux
Pull modules updates from Jessica Yu:
"Summary of modules changes for the 4.13 merge window:
- Minor code cleanups
- Avoid accessing mod struct prior to checking module struct version,
from Kees
- Fix racy atomic inc/dec logic of kmod_concurrent_max in kmod, from
Luis"
* tag 'modules-for-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
module: make the modinfo name const
kmod: reduce atomic operations on kmod_concurrent and simplify
module: use list_for_each_entry_rcu() on find_module_all()
kernel/module.c: suppress warning about unused nowarn variable
module: Add module name to modinfo
module: Pass struct load_info into symbol checks
hifive-unleashed-5.1
Linus Torvalds
commit
3a75ad1457
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@ -45,8 +45,6 @@
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#include <trace/events/module.h>
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extern int max_threads;
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#define CAP_BSET (void *)1
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#define CAP_PI (void *)2
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@ -56,6 +54,20 @@ static DEFINE_SPINLOCK(umh_sysctl_lock);
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static DECLARE_RWSEM(umhelper_sem);
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#ifdef CONFIG_MODULES
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/*
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* Assuming:
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*
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* threads = div64_u64((u64) totalram_pages * (u64) PAGE_SIZE,
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* (u64) THREAD_SIZE * 8UL);
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*
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* If you need less than 50 threads would mean we're dealing with systems
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* smaller than 3200 pages. This assuems you are capable of having ~13M memory,
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* and this would only be an be an upper limit, after which the OOM killer
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* would take effect. Systems like these are very unlikely if modules are
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* enabled.
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*/
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#define MAX_KMOD_CONCURRENT 50
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static atomic_t kmod_concurrent_max = ATOMIC_INIT(MAX_KMOD_CONCURRENT);
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/*
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modprobe_path is set via /proc/sys.
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@ -127,10 +139,7 @@ int __request_module(bool wait, const char *fmt, ...)
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{
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va_list args;
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char module_name[MODULE_NAME_LEN];
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unsigned int max_modprobes;
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int ret;
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static atomic_t kmod_concurrent = ATOMIC_INIT(0);
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#define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */
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static int kmod_loop_msg;
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/*
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@ -154,21 +163,7 @@ int __request_module(bool wait, const char *fmt, ...)
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if (ret)
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return ret;
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/* If modprobe needs a service that is in a module, we get a recursive
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* loop. Limit the number of running kmod threads to max_threads/2 or
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* MAX_KMOD_CONCURRENT, whichever is the smaller. A cleaner method
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* would be to run the parents of this process, counting how many times
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* kmod was invoked. That would mean accessing the internals of the
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* process tables to get the command line, proc_pid_cmdline is static
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* and it is not worth changing the proc code just to handle this case.
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* KAO.
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*
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* "trace the ppid" is simple, but will fail if someone's
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* parent exits. I think this is as good as it gets. --RR
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*/
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max_modprobes = min(max_threads/2, MAX_KMOD_CONCURRENT);
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atomic_inc(&kmod_concurrent);
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if (atomic_read(&kmod_concurrent) > max_modprobes) {
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if (atomic_dec_if_positive(&kmod_concurrent_max) < 0) {
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/* We may be blaming an innocent here, but unlikely */
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if (kmod_loop_msg < 5) {
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printk(KERN_ERR
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@ -176,7 +171,6 @@ int __request_module(bool wait, const char *fmt, ...)
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module_name);
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kmod_loop_msg++;
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}
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atomic_dec(&kmod_concurrent);
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return -ENOMEM;
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}
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@ -184,10 +178,12 @@ int __request_module(bool wait, const char *fmt, ...)
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ret = call_modprobe(module_name, wait ? UMH_WAIT_PROC : UMH_WAIT_EXEC);
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atomic_dec(&kmod_concurrent);
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atomic_inc(&kmod_concurrent_max);
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return ret;
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}
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EXPORT_SYMBOL(__request_module);
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#endif /* CONFIG_MODULES */
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static void call_usermodehelper_freeinfo(struct subprocess_info *info)
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@ -300,6 +300,7 @@ int unregister_module_notifier(struct notifier_block *nb)
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EXPORT_SYMBOL(unregister_module_notifier);
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struct load_info {
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const char *name;
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Elf_Ehdr *hdr;
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unsigned long len;
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Elf_Shdr *sechdrs;
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@ -600,7 +601,7 @@ static struct module *find_module_all(const char *name, size_t len,
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module_assert_mutex_or_preempt();
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list_for_each_entry(mod, &modules, list) {
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list_for_each_entry_rcu(mod, &modules, list) {
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if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
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continue;
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if (strlen(mod->name) == len && !memcmp(mod->name, name, len))
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@ -1273,12 +1274,13 @@ static u32 resolve_rel_crc(const s32 *crc)
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return *(u32 *)((void *)crc + *crc);
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}
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static int check_version(Elf_Shdr *sechdrs,
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unsigned int versindex,
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static int check_version(const struct load_info *info,
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const char *symname,
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struct module *mod,
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const s32 *crc)
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{
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Elf_Shdr *sechdrs = info->sechdrs;
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unsigned int versindex = info->index.vers;
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unsigned int i, num_versions;
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struct modversion_info *versions;
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@ -1312,17 +1314,16 @@ static int check_version(Elf_Shdr *sechdrs,
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}
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/* Broken toolchain. Warn once, then let it go.. */
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pr_warn_once("%s: no symbol version for %s\n", mod->name, symname);
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pr_warn_once("%s: no symbol version for %s\n", info->name, symname);
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return 1;
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bad_version:
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pr_warn("%s: disagrees about version of symbol %s\n",
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mod->name, symname);
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info->name, symname);
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return 0;
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}
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static inline int check_modstruct_version(Elf_Shdr *sechdrs,
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unsigned int versindex,
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static inline int check_modstruct_version(const struct load_info *info,
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struct module *mod)
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{
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const s32 *crc;
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@ -1338,8 +1339,8 @@ static inline int check_modstruct_version(Elf_Shdr *sechdrs,
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BUG();
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}
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preempt_enable();
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return check_version(sechdrs, versindex,
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VMLINUX_SYMBOL_STR(module_layout), mod, crc);
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return check_version(info, VMLINUX_SYMBOL_STR(module_layout),
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mod, crc);
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}
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/* First part is kernel version, which we ignore if module has crcs. */
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@ -1353,8 +1354,7 @@ static inline int same_magic(const char *amagic, const char *bmagic,
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return strcmp(amagic, bmagic) == 0;
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}
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#else
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static inline int check_version(Elf_Shdr *sechdrs,
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unsigned int versindex,
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static inline int check_version(const struct load_info *info,
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const char *symname,
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struct module *mod,
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const s32 *crc)
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@ -1362,8 +1362,7 @@ static inline int check_version(Elf_Shdr *sechdrs,
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return 1;
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}
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static inline int check_modstruct_version(Elf_Shdr *sechdrs,
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unsigned int versindex,
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static inline int check_modstruct_version(const struct load_info *info,
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struct module *mod)
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{
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return 1;
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@ -1399,7 +1398,7 @@ static const struct kernel_symbol *resolve_symbol(struct module *mod,
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if (!sym)
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goto unlock;
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if (!check_version(info->sechdrs, info->index.vers, name, mod, crc)) {
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if (!check_version(info, name, mod, crc)) {
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sym = ERR_PTR(-EINVAL);
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goto getname;
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}
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@ -1662,21 +1661,6 @@ static inline void remove_notes_attrs(struct module *mod)
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}
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#endif /* CONFIG_KALLSYMS */
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static void add_usage_links(struct module *mod)
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{
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#ifdef CONFIG_MODULE_UNLOAD
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struct module_use *use;
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int nowarn;
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mutex_lock(&module_mutex);
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list_for_each_entry(use, &mod->target_list, target_list) {
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nowarn = sysfs_create_link(use->target->holders_dir,
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&mod->mkobj.kobj, mod->name);
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}
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mutex_unlock(&module_mutex);
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#endif
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}
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static void del_usage_links(struct module *mod)
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{
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#ifdef CONFIG_MODULE_UNLOAD
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@ -1689,6 +1673,26 @@ static void del_usage_links(struct module *mod)
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#endif
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}
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static int add_usage_links(struct module *mod)
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{
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int ret = 0;
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#ifdef CONFIG_MODULE_UNLOAD
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struct module_use *use;
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mutex_lock(&module_mutex);
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list_for_each_entry(use, &mod->target_list, target_list) {
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ret = sysfs_create_link(use->target->holders_dir,
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&mod->mkobj.kobj, mod->name);
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if (ret)
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break;
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}
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mutex_unlock(&module_mutex);
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if (ret)
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del_usage_links(mod);
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#endif
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return ret;
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}
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static int module_add_modinfo_attrs(struct module *mod)
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{
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struct module_attribute *attr;
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@ -1797,13 +1801,18 @@ static int mod_sysfs_setup(struct module *mod,
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if (err)
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goto out_unreg_param;
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add_usage_links(mod);
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err = add_usage_links(mod);
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if (err)
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goto out_unreg_modinfo_attrs;
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add_sect_attrs(mod, info);
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add_notes_attrs(mod, info);
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kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD);
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return 0;
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out_unreg_modinfo_attrs:
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module_remove_modinfo_attrs(mod);
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out_unreg_param:
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module_param_sysfs_remove(mod);
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out_unreg_holders:
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@ -2910,9 +2919,15 @@ static int rewrite_section_headers(struct load_info *info, int flags)
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info->index.vers = 0; /* Pretend no __versions section! */
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else
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info->index.vers = find_sec(info, "__versions");
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info->index.info = find_sec(info, ".modinfo");
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info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
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info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;
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info->index.info = find_sec(info, ".modinfo");
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if (!info->index.info)
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info->name = "(missing .modinfo section)";
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else
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info->name = get_modinfo(info, "name");
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info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
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return 0;
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}
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@ -2952,21 +2967,29 @@ static struct module *setup_load_info(struct load_info *info, int flags)
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info->index.mod = find_sec(info, ".gnu.linkonce.this_module");
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if (!info->index.mod) {
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pr_warn("No module found in object\n");
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pr_warn("%s: No module found in object\n",
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info->name ?: "(missing .modinfo name field)");
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return ERR_PTR(-ENOEXEC);
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}
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/* This is temporary: point mod into copy of data. */
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mod = (void *)info->sechdrs[info->index.mod].sh_addr;
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/*
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* If we didn't load the .modinfo 'name' field, fall back to
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* on-disk struct mod 'name' field.
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*/
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if (!info->name)
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info->name = mod->name;
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if (info->index.sym == 0) {
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pr_warn("%s: module has no symbols (stripped?)\n", mod->name);
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pr_warn("%s: module has no symbols (stripped?)\n", info->name);
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return ERR_PTR(-ENOEXEC);
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}
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info->index.pcpu = find_pcpusec(info);
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/* Check module struct version now, before we try to use module. */
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if (!check_modstruct_version(info->sechdrs, info->index.vers, mod))
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if (!check_modstruct_version(info, mod))
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return ERR_PTR(-ENOEXEC);
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return mod;
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|
@ -2987,7 +3010,7 @@ static int check_modinfo(struct module *mod, struct load_info *info, int flags)
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return err;
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} else if (!same_magic(modmagic, vermagic, info->index.vers)) {
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pr_err("%s: version magic '%s' should be '%s'\n",
|
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mod->name, modmagic, vermagic);
|
||||
info->name, modmagic, vermagic);
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||||
return -ENOEXEC;
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||||
}
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||||
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|
@ -3237,7 +3260,7 @@ int __weak module_frob_arch_sections(Elf_Ehdr *hdr,
|
|||
|
||||
/* module_blacklist is a comma-separated list of module names */
|
||||
static char *module_blacklist;
|
||||
static bool blacklisted(char *module_name)
|
||||
static bool blacklisted(const char *module_name)
|
||||
{
|
||||
const char *p;
|
||||
size_t len;
|
||||
|
|
@ -3267,7 +3290,7 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
|
|||
if (IS_ERR(mod))
|
||||
return mod;
|
||||
|
||||
if (blacklisted(mod->name))
|
||||
if (blacklisted(info->name))
|
||||
return ERR_PTR(-EPERM);
|
||||
|
||||
err = check_modinfo(mod, info, flags);
|
||||
|
|
|
|||
|
|
@ -2126,6 +2126,7 @@ static void add_header(struct buffer *b, struct module *mod)
|
|||
buf_printf(b, "#include <linux/compiler.h>\n");
|
||||
buf_printf(b, "\n");
|
||||
buf_printf(b, "MODULE_INFO(vermagic, VERMAGIC_STRING);\n");
|
||||
buf_printf(b, "MODULE_INFO(name, KBUILD_MODNAME);\n");
|
||||
buf_printf(b, "\n");
|
||||
buf_printf(b, "__visible struct module __this_module\n");
|
||||
buf_printf(b, "__attribute__((section(\".gnu.linkonce.this_module\"))) = {\n");
|
||||
|
|
|
|||
Loading…
Reference in New Issue