diff options
| -rw-r--r-- | kernel/trace/fprobe.c | 67 |
1 files changed, 48 insertions, 19 deletions
diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c index 33082c4e8154..cb86f90d4b1e 100644 --- a/kernel/trace/fprobe.c +++ b/kernel/trace/fprobe.c @@ -445,6 +445,7 @@ struct filter_match_data { size_t index; size_t size; unsigned long *addrs; + struct module **mods; }; static int filter_match_callback(void *data, const char *name, unsigned long addr) @@ -458,30 +459,47 @@ static int filter_match_callback(void *data, const char *name, unsigned long add if (!ftrace_location(addr)) return 0; - if (match->addrs) - match->addrs[match->index] = addr; + if (match->addrs) { + struct module *mod = __module_text_address(addr); + + if (mod && !try_module_get(mod)) + return 0; + match->mods[match->index] = mod; + match->addrs[match->index] = addr; + } match->index++; return match->index == match->size; } /* * Make IP list from the filter/no-filter glob patterns. - * Return the number of matched symbols, or -ENOENT. + * Return the number of matched symbols, or errno. + * If @addrs == NULL, this just counts the number of matched symbols. If @addrs + * is passed with an array, we need to pass the an @mods array of the same size + * to increment the module refcount for each symbol. + * This means we also need to call `module_put` for each element of @mods after + * using the @addrs. */ -static int ip_list_from_filter(const char *filter, const char *notfilter, - unsigned long *addrs, size_t size) +static int get_ips_from_filter(const char *filter, const char *notfilter, + unsigned long *addrs, struct module **mods, + size_t size) { struct filter_match_data match = { .filter = filter, .notfilter = notfilter, - .index = 0, .size = size, .addrs = addrs}; + .index = 0, .size = size, .addrs = addrs, .mods = mods}; int ret; + if (addrs && !mods) + return -EINVAL; + ret = kallsyms_on_each_symbol(filter_match_callback, &match); if (ret < 0) return ret; - ret = module_kallsyms_on_each_symbol(NULL, filter_match_callback, &match); - if (ret < 0) - return ret; + if (IS_ENABLED(CONFIG_MODULES)) { + ret = module_kallsyms_on_each_symbol(NULL, filter_match_callback, &match); + if (ret < 0) + return ret; + } return match.index ?: -ENOENT; } @@ -543,24 +561,35 @@ static int fprobe_init(struct fprobe *fp, unsigned long *addrs, int num) */ int register_fprobe(struct fprobe *fp, const char *filter, const char *notfilter) { - unsigned long *addrs; - int ret; + unsigned long *addrs __free(kfree) = NULL; + struct module **mods __free(kfree) = NULL; + int ret, num; if (!fp || !filter) return -EINVAL; - ret = ip_list_from_filter(filter, notfilter, NULL, FPROBE_IPS_MAX); - if (ret < 0) - return ret; + num = get_ips_from_filter(filter, notfilter, NULL, NULL, FPROBE_IPS_MAX); + if (num < 0) + return num; - addrs = kcalloc(ret, sizeof(unsigned long), GFP_KERNEL); + addrs = kcalloc(num, sizeof(*addrs), GFP_KERNEL); if (!addrs) return -ENOMEM; - ret = ip_list_from_filter(filter, notfilter, addrs, ret); - if (ret > 0) - ret = register_fprobe_ips(fp, addrs, ret); - kfree(addrs); + mods = kcalloc(num, sizeof(*mods), GFP_KERNEL); + if (!mods) + return -ENOMEM; + + ret = get_ips_from_filter(filter, notfilter, addrs, mods, num); + if (ret < 0) + return ret; + + ret = register_fprobe_ips(fp, addrs, ret); + + for (int i = 0; i < num; i++) { + if (mods[i]) + module_put(mods[i]); + } return ret; } EXPORT_SYMBOL_GPL(register_fprobe); |