diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig.debug | 111 | ||||
| -rw-r--r-- | lib/Makefile | 2 | ||||
| -rw-r--r-- | lib/atomic64_test.c | 7 | ||||
| -rw-r--r-- | lib/fault-inject.c | 10 | ||||
| -rw-r--r-- | lib/percpu_counter.c | 7 | ||||
| -rw-r--r-- | lib/rhashtable.c | 2 | ||||
| -rw-r--r-- | lib/string.c | 7 | ||||
| -rw-r--r-- | lib/test_kmod.c | 1246 | ||||
| -rw-r--r-- | lib/test_sysctl.c | 148 |
9 files changed, 1522 insertions, 18 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index e20fc079bebd..98fe715522e8 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -778,34 +778,45 @@ config DEBUG_SHIRQ menu "Debug Lockups and Hangs" config LOCKUP_DETECTOR - bool "Detect Hard and Soft Lockups" + bool + +config SOFTLOCKUP_DETECTOR + bool "Detect Soft Lockups" depends on DEBUG_KERNEL && !S390 + select LOCKUP_DETECTOR help Say Y here to enable the kernel to act as a watchdog to detect - hard and soft lockups. + soft lockups. Softlockups are bugs that cause the kernel to loop in kernel mode for more than 20 seconds, without giving other tasks a chance to run. The current stack trace is displayed upon detection and the system will stay locked up. +config HARDLOCKUP_DETECTOR_PERF + bool + select SOFTLOCKUP_DETECTOR + +# +# arch/ can define HAVE_HARDLOCKUP_DETECTOR_ARCH to provide their own hard +# lockup detector rather than the perf based detector. +# +config HARDLOCKUP_DETECTOR + bool "Detect Hard Lockups" + depends on DEBUG_KERNEL && !S390 + depends on HAVE_HARDLOCKUP_DETECTOR_PERF || HAVE_HARDLOCKUP_DETECTOR_ARCH + select LOCKUP_DETECTOR + select HARDLOCKUP_DETECTOR_PERF if HAVE_HARDLOCKUP_DETECTOR_PERF + select HARDLOCKUP_DETECTOR_ARCH if HAVE_HARDLOCKUP_DETECTOR_ARCH + help + Say Y here to enable the kernel to act as a watchdog to detect + hard lockups. + Hardlockups are bugs that cause the CPU to loop in kernel mode for more than 10 seconds, without letting other interrupts have a chance to run. The current stack trace is displayed upon detection and the system will stay locked up. - The overhead should be minimal. A periodic hrtimer runs to - generate interrupts and kick the watchdog task every 4 seconds. - An NMI is generated every 10 seconds or so to check for hardlockups. - - The frequency of hrtimer and NMI events and the soft and hard lockup - thresholds can be controlled through the sysctl watchdog_thresh. - -config HARDLOCKUP_DETECTOR - def_bool y - depends on LOCKUP_DETECTOR && !HAVE_NMI_WATCHDOG - depends on PERF_EVENTS && HAVE_PERF_EVENTS_NMI - config BOOTPARAM_HARDLOCKUP_PANIC bool "Panic (Reboot) On Hard Lockups" depends on HARDLOCKUP_DETECTOR @@ -826,7 +837,7 @@ config BOOTPARAM_HARDLOCKUP_PANIC_VALUE config BOOTPARAM_SOFTLOCKUP_PANIC bool "Panic (Reboot) On Soft Lockups" - depends on LOCKUP_DETECTOR + depends on SOFTLOCKUP_DETECTOR help Say Y here to enable the kernel to panic on "soft lockups", which are bugs that cause the kernel to loop in kernel @@ -843,7 +854,7 @@ config BOOTPARAM_SOFTLOCKUP_PANIC config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE int - depends on LOCKUP_DETECTOR + depends on SOFTLOCKUP_DETECTOR range 0 1 default 0 if !BOOTPARAM_SOFTLOCKUP_PANIC default 1 if BOOTPARAM_SOFTLOCKUP_PANIC @@ -851,7 +862,7 @@ config BOOTPARAM_SOFTLOCKUP_PANIC_VALUE config DETECT_HUNG_TASK bool "Detect Hung Tasks" depends on DEBUG_KERNEL - default LOCKUP_DETECTOR + default SOFTLOCKUP_DETECTOR help Say Y here to enable the kernel to detect "hung tasks", which are bugs that cause the task to be stuck in @@ -1212,6 +1223,34 @@ config STACKTRACE It is also used by various kernel debugging features that require stack trace generation. +config WARN_ALL_UNSEEDED_RANDOM + bool "Warn for all uses of unseeded randomness" + default n + help + Some parts of the kernel contain bugs relating to their use of + cryptographically secure random numbers before it's actually possible + to generate those numbers securely. This setting ensures that these + flaws don't go unnoticed, by enabling a message, should this ever + occur. This will allow people with obscure setups to know when things + are going wrong, so that they might contact developers about fixing + it. + + Unfortunately, on some models of some architectures getting + a fully seeded CRNG is extremely difficult, and so this can + result in dmesg getting spammed for a surprisingly long + time. This is really bad from a security perspective, and + so architecture maintainers really need to do what they can + to get the CRNG seeded sooner after the system is booted. + However, since users can not do anything actionble to + address this, by default the kernel will issue only a single + warning for the first use of unseeded randomness. + + Say Y here if you want to receive warnings for all uses of + unseeded randomness. This will be of use primarily for + those developers interersted in improving the security of + Linux kernels running on their architecture (or + subarchitecture). + config DEBUG_KOBJECT bool "kobject debugging" depends on DEBUG_KERNEL @@ -1785,6 +1824,17 @@ config TEST_FIRMWARE If unsure, say N. +config TEST_SYSCTL + tristate "sysctl test driver" + default n + depends on PROC_SYSCTL + help + This builds the "test_sysctl" module. This driver enables to test the + proc sysctl interfaces available to drivers safely without affecting + production knobs which might alter system functionality. + + If unsure, say N. + config TEST_UDELAY tristate "udelay test driver" default n @@ -1825,6 +1875,33 @@ config BUG_ON_DATA_CORRUPTION If unsure, say N. +config TEST_KMOD + tristate "kmod stress tester" + default n + depends on m + depends on BLOCK && (64BIT || LBDAF) # for XFS, BTRFS + depends on NETDEVICES && NET_CORE && INET # for TUN + select TEST_LKM + select XFS_FS + select TUN + select BTRFS_FS + help + Test the kernel's module loading mechanism: kmod. kmod implements + support to load modules using the Linux kernel's usermode helper. + This test provides a series of tests against kmod. + + Although technically you can either build test_kmod as a module or + into the kernel we disallow building it into the kernel since + it stress tests request_module() and this will very likely cause + some issues by taking over precious threads available from other + module load requests, ultimately this could be fatal. + + To run tests run: + + tools/testing/selftests/kmod/kmod.sh --help + + If unsure, say N. + source "samples/Kconfig" source "lib/Kconfig.kgdb" diff --git a/lib/Makefile b/lib/Makefile index 5a008329324e..40c18372b301 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -46,6 +46,7 @@ obj-$(CONFIG_TEST_HEXDUMP) += test_hexdump.o obj-y += kstrtox.o obj-$(CONFIG_TEST_BPF) += test_bpf.o obj-$(CONFIG_TEST_FIRMWARE) += test_firmware.o +obj-$(CONFIG_TEST_SYSCTL) += test_sysctl.o obj-$(CONFIG_TEST_HASH) += test_hash.o test_siphash.o obj-$(CONFIG_TEST_KASAN) += test_kasan.o obj-$(CONFIG_TEST_KSTRTOX) += test-kstrtox.o @@ -60,6 +61,7 @@ obj-$(CONFIG_TEST_PRINTF) += test_printf.o obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o obj-$(CONFIG_TEST_UUID) += test_uuid.o obj-$(CONFIG_TEST_PARMAN) += test_parman.o +obj-$(CONFIG_TEST_KMOD) += test_kmod.o ifeq ($(CONFIG_DEBUG_KOBJECT),y) CFLAGS_kobject.o += -DDEBUG diff --git a/lib/atomic64_test.c b/lib/atomic64_test.c index fd70c0e0e673..62ab629f51ca 100644 --- a/lib/atomic64_test.c +++ b/lib/atomic64_test.c @@ -153,8 +153,10 @@ static __init void test_atomic64(void) long long v0 = 0xaaa31337c001d00dLL; long long v1 = 0xdeadbeefdeafcafeLL; long long v2 = 0xfaceabadf00df001LL; + long long v3 = 0x8000000000000000LL; long long onestwos = 0x1111111122222222LL; long long one = 1LL; + int r_int; atomic64_t v = ATOMIC64_INIT(v0); long long r = v0; @@ -240,6 +242,11 @@ static __init void test_atomic64(void) BUG_ON(!atomic64_inc_not_zero(&v)); r += one; BUG_ON(v.counter != r); + + /* Confirm the return value fits in an int, even if the value doesn't */ + INIT(v3); + r_int = atomic64_inc_not_zero(&v); + BUG_ON(!r_int); } static __init int test_atomics_init(void) diff --git a/lib/fault-inject.c b/lib/fault-inject.c index 4ff157159a0d..7d315fdb9f13 100644 --- a/lib/fault-inject.c +++ b/lib/fault-inject.c @@ -107,6 +107,15 @@ static inline bool fail_stacktrace(struct fault_attr *attr) bool should_fail(struct fault_attr *attr, ssize_t size) { + if (in_task()) { + unsigned int fail_nth = READ_ONCE(current->fail_nth); + + if (fail_nth && !WRITE_ONCE(current->fail_nth, fail_nth - 1)) + goto fail; + + return false; + } + /* No need to check any other properties if the probability is 0 */ if (attr->probability == 0) return false; @@ -134,6 +143,7 @@ bool should_fail(struct fault_attr *attr, ssize_t size) if (!fail_stacktrace(attr)) return false; +fail: fail_dump(attr); if (atomic_read(&attr->times) != -1) diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c index 8ee7e5ec21be..3bf4a9984f4c 100644 --- a/lib/percpu_counter.c +++ b/lib/percpu_counter.c @@ -72,6 +72,13 @@ void percpu_counter_set(struct percpu_counter *fbc, s64 amount) } EXPORT_SYMBOL(percpu_counter_set); +/** + * This function is both preempt and irq safe. The former is due to explicit + * preemption disable. The latter is guaranteed by the fact that the slow path + * is explicitly protected by an irq-safe spinlock whereas the fast patch uses + * this_cpu_add which is irq-safe by definition. Hence there is no need muck + * with irq state before calling this one + */ void percpu_counter_add_batch(struct percpu_counter *fbc, s64 amount, s32 batch) { s64 count; diff --git a/lib/rhashtable.c b/lib/rhashtable.c index 42466c167257..707ca5d677c6 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -234,7 +234,7 @@ static struct bucket_table *bucket_table_alloc(struct rhashtable *ht, INIT_LIST_HEAD(&tbl->walkers); - get_random_bytes(&tbl->hash_rnd, sizeof(tbl->hash_rnd)); + tbl->hash_rnd = get_random_u32(); for (i = 0; i < nbuckets; i++) INIT_RHT_NULLS_HEAD(tbl->buckets[i], ht, i); diff --git a/lib/string.c b/lib/string.c index 1c1fc9187b05..ebbb99c775bd 100644 --- a/lib/string.c +++ b/lib/string.c @@ -978,3 +978,10 @@ char *strreplace(char *s, char old, char new) return s; } EXPORT_SYMBOL(strreplace); + +void fortify_panic(const char *name) +{ + pr_emerg("detected buffer overflow in %s\n", name); + BUG(); +} +EXPORT_SYMBOL(fortify_panic); diff --git a/lib/test_kmod.c b/lib/test_kmod.c new file mode 100644 index 000000000000..6c1d678bcf8b --- /dev/null +++ b/lib/test_kmod.c @@ -0,0 +1,1246 @@ +/* + * kmod stress test driver + * + * Copyright (C) 2017 Luis R. Rodriguez <mcgrof@kernel.org> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or at your option any + * later version; or, when distributed separately from the Linux kernel or + * when incorporated into other software packages, subject to the following + * license: + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of copyleft-next (version 0.3.1 or later) as published + * at http://copyleft-next.org/. + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +/* + * This driver provides an interface to trigger and test the kernel's + * module loader through a series of configurations and a few triggers. + * To test this driver use the following script as root: + * + * tools/testing/selftests/kmod/kmod.sh --help + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/kmod.h> +#include <linux/printk.h> +#include <linux/kthread.h> +#include <linux/sched.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> +#include <linux/vmalloc.h> +#include <linux/slab.h> +#include <linux/device.h> + +#define TEST_START_NUM_THREADS 50 +#define TEST_START_DRIVER "test_module" +#define TEST_START_TEST_FS "xfs" +#define TEST_START_TEST_CASE TEST_KMOD_DRIVER + + +static bool force_init_test = false; +module_param(force_init_test, bool_enable_only, 0644); +MODULE_PARM_DESC(force_init_test, + "Force kicking a test immediately after driver loads"); + +/* + * For device allocation / registration + */ +static DEFINE_MUTEX(reg_dev_mutex); +static LIST_HEAD(reg_test_devs); + +/* + * num_test_devs actually represents the *next* ID of the next + * device we will allow to create. + */ +static int num_test_devs; + +/** + * enum kmod_test_case - linker table test case + * + * If you add a test case, please be sure to review if you need to se + * @need_mod_put for your tests case. + * + * @TEST_KMOD_DRIVER: stress tests request_module() + * @TEST_KMOD_FS_TYPE: stress tests get_fs_type() + */ +enum kmod_test_case { + __TEST_KMOD_INVALID = 0, + + TEST_KMOD_DRIVER, + TEST_KMOD_FS_TYPE, + + __TEST_KMOD_MAX, +}; + +struct test_config { + char *test_driver; + char *test_fs; + unsigned int num_threads; + enum kmod_test_case test_case; + int test_result; +}; + +struct kmod_test_device; + +/** + * kmod_test_device_info - thread info + * + * @ret_sync: return value if request_module() is used, sync request for + * @TEST_KMOD_DRIVER + * @fs_sync: return value of get_fs_type() for @TEST_KMOD_FS_TYPE + * @thread_idx: thread ID + * @test_dev: test device test is being performed under + * @need_mod_put: Some tests (get_fs_type() is one) requires putting the module + * (module_put(fs_sync->owner)) when done, otherwise you will not be able + * to unload the respective modules and re-test. We use this to keep + * accounting of when we need this and to help out in case we need to + * error out and deal with module_put() on error. + */ +struct kmod_test_device_info { + int ret_sync; + struct file_system_type *fs_sync; + struct task_struct *task_sync; + unsigned int thread_idx; + struct kmod_test_device *test_dev; + bool need_mod_put; +}; + +/** + * kmod_test_device - test device to help test kmod + * + * @dev_idx: unique ID for test device + * @config: configuration for the test + * @misc_dev: we use a misc device under the hood + * @dev: pointer to misc_dev's own struct device + * @config_mutex: protects configuration of test + * @trigger_mutex: the test trigger can only be fired once at a time + * @thread_lock: protects @done count, and the @info per each thread + * @done: number of threads which have completed or failed + * @test_is_oom: when we run out of memory, use this to halt moving forward + * @kthreads_done: completion used to signal when all work is done + * @list: needed to be part of the reg_test_devs + * @info: array of info for each thread + */ +struct kmod_test_device { + int dev_idx; + struct test_config config; + struct miscdevice misc_dev; + struct device *dev; + struct mutex config_mutex; + struct mutex trigger_mutex; + struct mutex thread_mutex; + + unsigned int done; + + bool test_is_oom; + struct completion kthreads_done; + struct list_head list; + + struct kmod_test_device_info *info; +}; + +static const char *test_case_str(enum kmod_test_case test_case) +{ + switch (test_case) { + case TEST_KMOD_DRIVER: + return "TEST_KMOD_DRIVER"; + case TEST_KMOD_FS_TYPE: + return "TEST_KMOD_FS_TYPE"; + default: + return "invalid"; + } +} + +static struct miscdevice *dev_to_misc_dev(struct device *dev) +{ + return dev_get_drvdata(dev); +} + +static struct kmod_test_device *misc_dev_to_test_dev(struct miscdevice *misc_dev) +{ + return container_of(misc_dev, struct kmod_test_device, misc_dev); +} + +static struct kmod_test_device *dev_to_test_dev(struct device *dev) +{ + struct miscdevice *misc_dev; + + misc_dev = dev_to_misc_dev(dev); + + return misc_dev_to_test_dev(misc_dev); +} + +/* Must run with thread_mutex held */ +static void kmod_test_done_check(struct kmod_test_device *test_dev, + unsigned int idx) +{ + struct test_config *config = &test_dev->config; + + test_dev->done++; + dev_dbg(test_dev->dev, "Done thread count: %u\n", test_dev->done); + + if (test_dev->done == config->num_threads) { + dev_info(test_dev->dev, "Done: %u threads have all run now\n", + test_dev->done); + dev_info(test_dev->dev, "Last thread to run: %u\n", idx); + complete(&test_dev->kthreads_done); + } +} + +static void test_kmod_put_module(struct kmod_test_device_info *info) +{ + struct kmod_test_device *test_dev = info->test_dev; + struct test_config *config = &test_dev->config; + + if (!info->need_mod_put) + return; + + switch (config->test_case) { + case TEST_KMOD_DRIVER: + break; + case TEST_KMOD_FS_TYPE: + if (info && info->fs_sync && info->fs_sync->owner) + module_put(info->fs_sync->owner); + break; + default: + BUG(); + } + + info->need_mod_put = true; +} + +static int run_request(void *data) +{ + struct kmod_test_device_info *info = data; + struct kmod_test_device *test_dev = info->test_dev; + struct test_config *config = &test_dev->config; + + switch (config->test_case) { + case TEST_KMOD_DRIVER: + info->ret_sync = request_module("%s", config->test_driver); + break; + case TEST_KMOD_FS_TYPE: + info->fs_sync = get_fs_type(config->test_fs); + info->need_mod_put = true; + break; + default: + /* __trigger_config_run() already checked for test sanity */ + BUG(); + return -EINVAL; + } + + dev_dbg(test_dev->dev, "Ran thread %u\n", info->thread_idx); + + test_kmod_put_module(info); + + mutex_lock(&test_dev->thread_mutex); + info->task_sync = NULL; + kmod_test_done_check(test_dev, info->thread_idx); + mutex_unlock(&test_dev->thread_mutex); + + return 0; +} + +static int tally_work_test(struct kmod_test_device_info *info) +{ + struct kmod_test_device *test_dev = info->test_dev; + struct test_config *config = &test_dev->config; + int err_ret = 0; + + switch (config->test_case) { + case TEST_KMOD_DRIVER: + /* + * Only capture errors, if one is found that's + * enough, for now. + */ + if (info->ret_sync != 0) + err_ret = info->ret_sync; + dev_info(test_dev->dev, + "Sync thread %d return status: %d\n", + info->thread_idx, info->ret_sync); + break; + case TEST_KMOD_FS_TYPE: + /* For now we make this simple */ + if (!info->fs_sync) + err_ret = -EINVAL; + dev_info(test_dev->dev, "Sync thread %u fs: %s\n", + info->thread_idx, info->fs_sync ? config->test_fs : + "NULL"); + break; + default: + BUG(); + } + + return err_ret; +} + +/* + * XXX: add result option to display if all errors did not match. + * For now we just keep any error code if one was found. + * + * If this ran it means *all* tasks were created fine and we + * are now just collecting results. + * + * Only propagate errors, do not override with a subsequent sucess case. + */ +static void tally_up_work(struct kmod_test_device *test_dev) +{ + struct test_config *config = &test_dev->config; + struct kmod_test_device_info *info; + unsigned int idx; + int err_ret = 0; + int ret = 0; + + mutex_lock(&test_dev->thread_mutex); + + dev_info(test_dev->dev, "Results:\n"); + + for (idx=0; idx < config->num_threads; idx++) { + info = &test_dev->info[idx]; + ret = tally_work_test(info); + if (ret) + err_ret = ret; + } + + /* + * Note: request_module() returns 256 for a module not found even + * though modprobe itself returns 1. + */ + config->test_result = err_ret; + + mutex_unlock(&test_dev->thread_mutex); +} + +static int try_one_request(struct kmod_test_device *test_dev, unsigned int idx) +{ + struct kmod_test_device_info *info = &test_dev->info[idx]; + int fail_ret = -ENOMEM; + + mutex_lock(&test_dev->thread_mutex); + + info->thread_idx = idx; + info->test_dev = test_dev; + info->task_sync = kthread_run(run_request, info, "%s-%u", + KBUILD_MODNAME, idx); + + if (!info->task_sync || IS_ERR(info->task_sync)) { + test_dev->test_is_oom = true; + dev_err(test_dev->dev, "Setting up thread %u failed\n", idx); + info->task_sync = NULL; + goto err_out; + } else + dev_dbg(test_dev->dev, "Kicked off thread %u\n", idx); + + mutex_unlock(&test_dev->thread_mutex); + + return 0; + +err_out: + info->ret_sync = fail_ret; + mutex_unlock(&test_dev->thread_mutex); + + return fail_ret; +} + +static void test_dev_kmod_stop_tests(struct kmod_test_device *test_dev) +{ + struct test_config *config = &test_dev->config; + struct kmod_test_device_info *info; + unsigned int i; + + dev_info(test_dev->dev, "Ending request_module() tests\n"); + + mutex_lock(&test_dev->thread_mutex); + + for (i=0; i < config->num_threads; i++) { + info = &test_dev->info[i]; + if (info->task_sync && !IS_ERR(info->task_sync)) { + dev_info(test_dev->dev, + "Stopping still-running thread %i\n", i); + kthread_stop(info->task_sync); + } + + /* + * info->task_sync is well protected, it can only be + * NULL or a pointer to a struct. If its NULL we either + * never ran, or we did and we completed the work. Completed + * tasks *always* put the module for us. This is a sanity + * check -- just in case. + */ + if (info->task_sync && info->need_mod_put) + test_kmod_put_module(info); + } + + mutex_unlock(&test_dev->thread_mutex); +} + +/* + * Only wait *iff* we did not run into any errors during all of our thread + * set up. If run into any issues we stop threads and just bail out with + * an error to the trigger. This also means we don't need any tally work + * for any threads which fail. + */ +static int try_requests(struct kmod_test_device *test_dev) +{ + struct test_config *config = &test_dev->config; + unsigned int idx; + int ret; + bool any_error = false; + + for (idx=0; idx < config->num_threads; idx++) { + if (test_dev->test_is_oom) { + any_error = true; + break; + } + + ret = try_one_request(test_dev, idx); + if (ret) { + any_error = true; + break; + } + } + + if (!any_error) { + test_dev->test_is_oom = false; + dev_info(test_dev->dev, + "No errors were found while initializing threads\n"); + wait_for_completion(&test_dev->kthreads_done); + tally_up_work(test_dev); + } else { + test_dev->test_is_oom = true; + dev_info(test_dev->dev, + "At least one thread failed to start, stop all work\n"); + test_dev_kmod_stop_tests(test_dev); + return -ENOMEM; + } + + return 0; +} + +static int run_test_driver(struct kmod_test_device *test_dev) +{ + struct test_config *config = &test_dev->config; + + dev_info(test_dev->dev, "Test case: %s (%u)\n", + test_case_str(config->test_case), + config->test_case); + dev_info(test_dev->dev, "Test driver to load: %s\n", + config->test_driver); + dev_info(test_dev->dev, "Number of threads to run: %u\n", + config->num_threads); + dev_info(test_dev->dev, "Thread IDs will range from 0 - %u\n", + config->num_threads - 1); + + return try_requests(test_dev); +} + +static int run_test_fs_type(struct kmod_test_device *test_dev) +{ + struct test_config *config = &test_dev->config; + + dev_info(test_dev->dev, "Test case: %s (%u)\n", + test_case_str(config->test_case), + config->test_case); + dev_info(test_dev->dev, "Test filesystem to load: %s\n", + config->test_fs); + dev_info(test_dev->dev, "Number of threads to run: %u\n", + config->num_threads); + dev_info(test_dev->dev, "Thread IDs will range from 0 - %u\n", + config->num_threads - 1); + + return try_requests(test_dev); +} + +static ssize_t config_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct kmod_test_device *test_dev = dev_to_test_dev(dev); + struct test_config *config = &test_dev->config; + int len = 0; + + mutex_lock(&test_dev->config_mutex); + + len += snprintf(buf, PAGE_SIZE, + "Custom trigger configuration for: %s\n", + dev_name(dev)); + + len += snprintf(buf+len, PAGE_SIZE - len, + "Number of threads:\t%u\n", + config->num_threads); + + len += snprintf(buf+len, PAGE_SIZE - len, + "Test_case:\t%s (%u)\n", + test_case_str(config->test_case), + config->test_case); + + if (config->test_driver) + len += snprintf(buf+len, PAGE_SIZE - len, + "driver:\t%s\n", + config->test_driver); + else + len += snprintf(buf+len, PAGE_SIZE - len, + "driver:\tEMTPY\n"); + + if (config->test_fs) + len += snprintf(buf+len, PAGE_SIZE - len, + "fs:\t%s\n", + config->test_fs); + else + len += snprintf(buf+len, PAGE_SIZE - len, + "fs:\tEMTPY\n"); + + mutex_unlock(&test_dev->config_mutex); + + return len; +} +static DEVICE_ATTR_RO(config); + +/* + * This ensures we don't allow kicking threads through if our configuration + * is faulty. + */ +static int __trigger_config_run(struct kmod_test_device *test_dev) +{ + struct test_config *config = &test_dev->config; + + test_dev->done = 0; + + switch (config->test_case) { + case TEST_KMOD_DRIVER: + return run_test_driver(test_dev); + case TEST_KMOD_FS_TYPE: + return run_test_fs_type(test_dev); + default: + dev_warn(test_dev->dev, + "Invalid test case requested: %u\n", + config->test_case); + return -EINVAL; + } +} + +static int trigger_config_run(struct kmod_test_device *test_dev) +{ + struct test_config *config = &test_dev->config; + int ret; + + mutex_lock(&test_dev->trigger_mutex); + mutex_lock(&test_dev->config_mutex); + + ret = __trigger_config_run(test_dev); + if (ret < 0) + goto out; + dev_info(test_dev->dev, "General test result: %d\n", + config->test_result); + + /* + * We must return 0 after a trigger even unless something went + * wrong with the setup of the test. If the test setup went fine + * then userspace must just check the result of config->test_result. + * One issue with relying on the return from a call in the kernel + * is if the kernel returns a possitive value using this trigger + * will not return the value to userspace, it would be lost. + * + * By not relying on capturing the return value of tests we are using + * through the trigger it also us to run tests with set -e and only + * fail when something went wrong with the driver upon trigger + * requests. + */ + ret = 0; + +out: + mutex_unlock(&test_dev->config_mutex); + mutex_unlock(&test_dev->trigger_mutex); + + return ret; +} + +static ssize_t +trigger_config_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct kmod_test_device *test_dev = dev_to_test_dev(dev); + int ret; + + if (test_dev->test_is_oom) + return -ENOMEM; + + /* For all intents and purposes we don't care what userspace + * sent this trigger, we care only that we were triggered. + * We treat the return value only for caputuring issues with + * the test setup. At this point all the test variables should + * have been allocated so typically this should never fail. + */ + ret = trigger_config_run(test_dev); + if (unlikely(ret < 0)) + goto out; + + /* + * Note: any return > 0 will be treated as success + * and the error value will not be available to userspace. + * Do not rely on trying to send to userspace a test value + * return value as possitive return errors will be lost. + */ + if (WARN_ON(ret > 0)) + return -EINVAL; + + ret = count; +out: + return ret; +} +static DEVICE_ATTR_WO(trigger_config); + +/* + * XXX: move to kstrncpy() once merged. + * + * Users should use kfree_const() when freeing these. + */ +static int __kstrncpy(char **dst, const char *name, size_t count, gfp_t gfp) +{ + *dst = kstrndup(name, count, gfp); + if (!*dst) + return -ENOSPC; + return count; +} + +static int config_copy_test_driver_name(struct test_config *config, + const char *name, + size_t count) +{ + return __kstrncpy(&config->test_driver, name, count, GFP_KERNEL); +} + + +static int config_copy_test_fs(struct test_config *config, const char *name, + size_t count) +{ + return __kstrncpy(&config->test_fs, name, count, GFP_KERNEL); +} + +static void __kmod_config_free(struct test_config *config) +{ + if (!config) + return; + + kfree_const(config->test_driver); + config->test_driver = NULL; + + kfree_const(config->test_fs); + config->test_driver = NULL; +} + +static void kmod_config_free(struct kmod_test_device *test_dev) +{ + struct test_config *config; + + if (!test_dev) + return; + + config = &test_dev->config; + + mutex_lock(&test_dev->config_mutex); + __kmod_config_free(config); + mutex_unlock(&test_dev->config_mutex); +} + +static ssize_t config_test_driver_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct kmod_test_device *test_dev = dev_to_test_dev(dev); + struct test_config *config = &test_dev->config; + int copied; + + mutex_lock(&test_dev->config_mutex); + + kfree_const(config->test_driver); + config->test_driver = NULL; + + copied = config_copy_test_driver_name(config, buf, count); + mutex_unlock(&test_dev->config_mutex); + + return copied; +} + +/* + * As per sysfs_kf_seq_show() the buf is max PAGE_SIZE. + */ +static ssize_t config_test_show_str(struct mutex *config_mutex, + char *dst, + char *src) +{ + int len; + + mutex_lock(config_mutex); + len = snprintf(dst, PAGE_SIZE, "%s\n", src); + mutex_unlock(config_mutex); + + return len; +} + +static ssize_t config_test_driver_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct kmod_test_device *test_dev = dev_to_test_dev(dev); + struct test_config *config = &test_dev->config; + + return config_test_show_str(&test_dev->config_mutex, buf, + config->test_driver); +} +static DEVICE_ATTR(config_test_driver, 0644, config_test_driver_show, + config_test_driver_store); + +static ssize_t config_test_fs_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct kmod_test_device *test_dev = dev_to_test_dev(dev); + struct test_config *config = &test_dev->config; + int copied; + + mutex_lock(&test_dev->config_mutex); + + kfree_const(config->test_fs); + config->test_fs = NULL; + + copied = config_copy_test_fs(config, buf, count); + mutex_unlock(&test_dev->config_mutex); + + return copied; +} + +static ssize_t config_test_fs_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct kmod_test_device *test_dev = dev_to_test_dev(dev); + struct test_config *config = &test_dev->config; + + return config_test_show_str(&test_dev->config_mutex, buf, + config->test_fs); +} +static DEVICE_ATTR(config_test_fs, 0644, config_test_fs_show, + config_test_fs_store); + +static int trigger_config_run_type(struct kmod_test_device *test_dev, + enum kmod_test_case test_case, + const char *test_str) +{ + int copied = 0; + struct test_config *config = &test_dev->config; + + mutex_lock(&test_dev->config_mutex); + + switch (test_case) { + case TEST_KMOD_DRIVER: + kfree_const(config->test_driver); + config->test_driver = NULL; + copied = config_copy_test_driver_name(config, test_str, + strlen(test_str)); + break; + case TEST_KMOD_FS_TYPE: + break; + kfree_const(config->test_fs); + config->test_driver = NULL; + copied = config_copy_test_fs(config, test_str, + strlen(test_str)); + default: + mutex_unlock(&test_dev->config_mutex); + return -EINVAL; + } + + config->test_case = test_case; + + mutex_unlock(&test_dev->config_mutex); + + if (copied <= 0 || copied != strlen(test_str)) { + test_dev->test_is_oom = true; + return -ENOMEM; + } + + test_dev->test_is_oom = false; + + return trigger_config_run(test_dev); +} + +static void free_test_dev_info(struct kmod_test_device *test_dev) +{ + vfree(test_dev->info); + test_dev->info = NULL; +} + +static int kmod_config_sync_info(struct kmod_test_device *test_dev) +{ + struct test_config *config = &test_dev->config; + + free_test_dev_info(test_dev); + test_dev->info = vzalloc(config->num_threads * + sizeof(struct kmod_test_device_info)); + if (!test_dev->info) { + dev_err(test_dev->dev, "Cannot alloc test_dev info\n"); + return -ENOMEM; + } + + return 0; +} + +/* + * Old kernels may not have this, if you want to port this code to + * test it on older kernels. + */ +#ifdef get_kmod_umh_limit +static unsigned int kmod_init_test_thread_limit(void) +{ + return get_kmod_umh_limit(); +} +#else +static unsigned int kmod_init_test_thread_limit(void) +{ + return TEST_START_NUM_THREADS; +} +#endif + +static int __kmod_config_init(struct kmod_test_device *test_dev) +{ + struct test_config *config = &test_dev->config; + int ret = -ENOMEM, copied; + + __kmod_config_free(config); + + copied = config_copy_test_driver_name(config, TEST_START_DRIVER, + strlen(TEST_START_DRIVER)); + if (copied != strlen(TEST_START_DRIVER)) + goto err_out; + + copied = config_copy_test_fs(config, TEST_START_TEST_FS, + strlen(TEST_START_TEST_FS)); + if (copied != strlen(TEST_START_TEST_FS)) + goto err_out; + + config->num_threads = kmod_init_test_thread_limit(); + config->test_result = 0; + config->test_case = TEST_START_TEST_CASE; + + ret = kmod_config_sync_info(test_dev); + if (ret) + goto err_out; + + test_dev->test_is_oom = false; + + return 0; + +err_out: + test_dev->test_is_oom = true; + WARN_ON(test_dev->test_is_oom); + + __kmod_config_free(config); + + return ret; +} + +static ssize_t reset_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct kmod_test_device *test_dev = dev_to_test_dev(dev); + int ret; + + mutex_lock(&test_dev->trigger_mutex); + mutex_lock(&test_dev->config_mutex); + + ret = __kmod_config_init(test_dev); + if (ret < 0) { + ret = -ENOMEM; + dev_err(dev, "could not alloc settings for config trigger: %d\n", + ret); + goto out; + } + + dev_info(dev, "reset\n"); + ret = count; + +out: + mutex_unlock(&test_dev->config_mutex); + mutex_unlock(&test_dev->trigger_mutex); + + return ret; +} +static DEVICE_ATTR_WO(reset); + +static int test_dev_config_update_uint_sync(struct kmod_test_device *test_dev, + const char *buf, size_t size, + unsigned int *config, + int (*test_sync)(struct kmod_test_device *test_dev)) +{ + int ret; + long new; + unsigned int old_val; + + ret = kstrtol(buf, 10, &new); + if (ret) + return ret; + + if (new > UINT_MAX) + return -EINVAL; + + mutex_lock(&test_dev->config_mutex); + + old_val = *config; + *(unsigned int *)config = new; + + ret = test_sync(test_dev); + if (ret) { + *(unsigned int *)config = old_val; + + ret = test_sync(test_dev); + WARN_ON(ret); + + mutex_unlock(&test_dev->config_mutex); + return -EINVAL; + } + + mutex_unlock(&test_dev->config_mutex); + /* Always return full write size even if we didn't consume all */ + return size; +} + +static int test_dev_config_update_uint_range(struct kmod_test_device *test_dev, + const char *buf, size_t size, + unsigned int *config, + unsigned int min, + unsigned int max) +{ + int ret; + long new; + + ret = kstrtol(buf, 10, &new); + if (ret) + return ret; + + if (new < min || new > max || new > UINT_MAX) + return -EINVAL; + + mutex_lock(&test_dev->config_mutex); + *config = new; + mutex_unlock(&test_dev->config_mutex); + + /* Always return full write size even if we didn't consume all */ + return size; +} + +static int test_dev_config_update_int(struct kmod_test_device *test_dev, + const char *buf, size_t size, + int *config) +{ + int ret; + long new; + + ret = kstrtol(buf, 10, &new); + if (ret) + return ret; + + if (new > INT_MAX || new < INT_MIN) + return -EINVAL; + + mutex_lock(&test_dev->config_mutex); + *config = new; + mutex_unlock(&test_dev->config_mutex); + /* Always return full write size even if we didn't consume all */ + return size; +} + +static ssize_t test_dev_config_show_int(struct kmod_test_device *test_dev, + char *buf, + int config) +{ + int val; + + mutex_lock(&test_dev->config_mutex); + val = config; + mutex_unlock(&test_dev->config_mutex); + + return snprintf(buf, PAGE_SIZE, "%d\n", val); +} + +static ssize_t test_dev_config_show_uint(struct kmod_test_device *test_dev, + char *buf, + unsigned int config) +{ + unsigned int val; + + mutex_lock(&test_dev->config_mutex); + val = config; + mutex_unlock(&test_dev->config_mutex); + + return snprintf(buf, PAGE_SIZE, "%u\n", val); +} + +static ssize_t test_result_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct kmod_test_device *test_dev = dev_to_test_dev(dev); + struct test_config *config = &test_dev->config; + + return test_dev_config_update_int(test_dev, buf, count, + &config->test_result); +} + +static ssize_t config_num_threads_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct kmod_test_device *test_dev = dev_to_test_dev(dev); + struct test_config *config = &test_dev->config; + + return test_dev_config_update_uint_sync(test_dev, buf, count, + &config->num_threads, + kmod_config_sync_info); +} + +static ssize_t config_num_threads_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct kmod_test_device *test_dev = dev_to_test_dev(dev); + struct test_config *config = &test_dev->config; + + return test_dev_config_show_int(test_dev, buf, config->num_threads); +} +static DEVICE_ATTR(config_num_threads, 0644, config_num_threads_show, + config_num_threads_store); + +static ssize_t config_test_case_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct kmod_test_device *test_dev = dev_to_test_dev(dev); + struct test_config *config = &test_dev->config; + + return test_dev_config_update_uint_range(test_dev, buf, count, + &config->test_case, + __TEST_KMOD_INVALID + 1, + __TEST_KMOD_MAX - 1); +} + +static ssize_t config_test_case_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct kmod_test_device *test_dev = dev_to_test_dev(dev); + struct test_config *config = &test_dev->config; + + return test_dev_config_show_uint(test_dev, buf, config->test_case); +} +static DEVICE_ATTR(config_test_case, 0644, config_test_case_show, + config_test_case_store); + +static ssize_t test_result_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct kmod_test_device *test_dev = dev_to_test_dev(dev); + struct test_config *config = &test_dev->config; + + return test_dev_config_show_int(test_dev, buf, config->test_result); +} +static DEVICE_ATTR(test_result, 0644, test_result_show, test_result_store); + +#define TEST_KMOD_DEV_ATTR(name) &dev_attr_##name.attr + +static struct attribute *test_dev_attrs[] = { + TEST_KMOD_DEV_ATTR(trigger_config), + TEST_KMOD_DEV_ATTR(config), + TEST_KMOD_DEV_ATTR(reset), + + TEST_KMOD_DEV_ATTR(config_test_driver), + TEST_KMOD_DEV_ATTR(config_test_fs), + TEST_KMOD_DEV_ATTR(config_num_threads), + TEST_KMOD_DEV_ATTR(config_test_case), + TEST_KMOD_DEV_ATTR(test_result), + + NULL, +}; + +ATTRIBUTE_GROUPS(test_dev); + +static int kmod_config_init(struct kmod_test_device *test_dev) +{ + int ret; + + mutex_lock(&test_dev->config_mutex); + ret = __kmod_config_init(test_dev); + mutex_unlock(&test_dev->config_mutex); + + return ret; +} + +static struct kmod_test_device *alloc_test_dev_kmod(int idx) +{ + int ret; + struct kmod_test_device *test_dev; + struct miscdevice *misc_dev; + + test_dev = vzalloc(sizeof(struct kmod_test_device)); + if (!test_dev) { + pr_err("Cannot alloc test_dev\n"); + goto err_out; + } + + mutex_init(&test_dev->config_mutex); + mutex_init(&test_dev->trigger_mutex); + mutex_init(&test_dev->thread_mutex); + + init_completion(&test_dev->kthreads_done); + + ret = kmod_config_init(test_dev); + if (ret < 0) { + pr_err("Cannot alloc kmod_config_init()\n"); + goto err_out_free; + } + + test_dev->dev_idx = idx; + misc_dev = &test_dev->misc_dev; + + misc_dev->minor = MISC_DYNAMIC_MINOR; + misc_dev->name = kasprintf(GFP_KERNEL, "test_kmod%d", idx); + if (!misc_dev->name) { + pr_err("Cannot alloc misc_dev->name\n"); + goto err_out_free_config; + } + misc_dev->groups = test_dev_groups; + + return test_dev; + +err_out_free_config: + free_test_dev_info(test_dev); + kmod_config_free(test_dev); +err_out_free: + vfree(test_dev); + test_dev = NULL; +err_out: + return NULL; +} + +static void free_test_dev_kmod(struct kmod_test_device *test_dev) +{ + if (test_dev) { + kfree_const(test_dev->misc_dev.name); + test_dev->misc_dev.name = NULL; + free_test_dev_info(test_dev); + kmod_config_free(test_dev); + vfree(test_dev); + test_dev = NULL; + } +} + +static struct kmod_test_device *register_test_dev_kmod(void) +{ + struct kmod_test_device *test_dev = NULL; + int ret; + + mutex_unlock(®_dev_mutex); + + /* int should suffice for number of devices, test for wrap */ + if (unlikely(num_test_devs + 1) < 0) { + pr_err("reached limit of number of test devices\n"); + goto out; + } + + test_dev = alloc_test_dev_kmod(num_test_devs); + if (!test_dev) + goto out; + + ret = misc_register(&test_dev->misc_dev); + if (ret) { + pr_err("could not register misc device: %d\n", ret); + free_test_dev_kmod(test_dev); + goto out; + } + + test_dev->dev = test_dev->misc_dev.this_device; + list_add_tail(&test_dev->list, ®_test_devs); + dev_info(test_dev->dev, "interface ready\n"); + + num_test_devs++; + +out: + mutex_unlock(®_dev_mutex); + + return test_dev; + +} + +static int __init test_kmod_init(void) +{ + struct kmod_test_device *test_dev; + int ret; + + test_dev = register_test_dev_kmod(); + if (!test_dev) { + pr_err("Cannot add first test kmod device\n"); + return -ENODEV; + } + + /* + * With some work we might be able to gracefully enable + * testing with this driver built-in, for now this seems + * rather risky. For those willing to try have at it, + * and enable the below. Good luck! If that works, try + * lowering the init level for more fun. + */ + if (force_init_test) { + ret = trigger_config_run_type(test_dev, + TEST_KMOD_DRIVER, "tun"); + if (WARN_ON(ret)) + return ret; + ret = trigger_config_run_type(test_dev, + TEST_KMOD_FS_TYPE, "btrfs"); + if (WARN_ON(ret)) + return ret; + } + + return 0; +} +late_initcall(test_kmod_init); + +static +void unregister_test_dev_kmod(struct kmod_test_device *test_dev) +{ + mutex_lock(&test_dev->trigger_mutex); + mutex_lock(&test_dev->config_mutex); + + test_dev_kmod_stop_tests(test_dev); + + dev_info(test_dev->dev, "removing interface\n"); + misc_deregister(&test_dev->misc_dev); + kfree(&test_dev->misc_dev.name); + + mutex_unlock(&test_dev->config_mutex); + mutex_unlock(&test_dev->trigger_mutex); + + free_test_dev_kmod(test_dev); +} + +static void __exit test_kmod_exit(void) +{ + struct kmod_test_device *test_dev, *tmp; + + mutex_lock(®_dev_mutex); + list_for_each_entry_safe(test_dev, tmp, ®_test_devs, list) { + list_del(&test_dev->list); + unregister_test_dev_kmod(test_dev); + } + mutex_unlock(®_dev_mutex); +} +module_exit(test_kmod_exit); + +MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>"); +MODULE_LICENSE("GPL"); diff --git a/lib/test_sysctl.c b/lib/test_sysctl.c new file mode 100644 index 000000000000..3dd801c1c85b --- /dev/null +++ b/lib/test_sysctl.c @@ -0,0 +1,148 @@ +/* + * proc sysctl test driver + * + * Copyright (C) 2017 Luis R. Rodriguez <mcgrof@kernel.org> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the Free + * Software Foundation; either version 2 of the License, or at your option any + * later version; or, when distributed separately from the Linux kernel or + * when incorporated into other software packages, subject to the following + * license: + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of copyleft-next (version 0.3.1 or later) as published + * at http://copyleft-next.org/. + */ + +/* + * This module provides an interface to the the proc sysctl interfaces. This + * driver requires CONFIG_PROC_SYSCTL. It will not normally be loaded by the + * system unless explicitly requested by name. You can also build this driver + * into your kernel. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/init.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/printk.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> +#include <linux/slab.h> +#include <linux/uaccess.h> +#include <linux/async.h> +#include <linux/delay.h> +#include <linux/vmalloc.h> + +static int i_zero; +static int i_one_hundred = 100; + +struct test_sysctl_data { + int int_0001; + int int_0002; + int int_0003[4]; + + unsigned int uint_0001; + + char string_0001[65]; +}; + +static struct test_sysctl_data test_data = { + .int_0001 = 60, + .int_0002 = 1, + + .int_0003[0] = 0, + .int_0003[1] = 1, + .int_0003[2] = 2, + .int_0003[3] = 3, + + .uint_0001 = 314, + + .string_0001 = "(none)", +}; + +/* These are all under /proc/sys/debug/test_sysctl/ */ +static struct ctl_table test_table[] = { + { + .procname = "int_0001", + .data = &test_data.int_0001, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &i_zero, + .extra2 = &i_one_hundred, + }, + { + .procname = "int_0002", + .data = &test_data.int_0002, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { + .procname = "int_0003", + .data = &test_data.int_0003, + .maxlen = sizeof(test_data.int_0003), + .mode = 0644, + .proc_handler = proc_dointvec, + }, + { + .procname = "uint_0001", + .data = &test_data.uint_0001, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_douintvec, + }, + { + .procname = "string_0001", + .data = &test_data.string_0001, + .maxlen = sizeof(test_data.string_0001), + .mode = 0644, + .proc_handler = proc_dostring, + }, + { } +}; + +static struct ctl_table test_sysctl_table[] = { + { + .procname = "test_sysctl", + .maxlen = 0, + .mode = 0555, + .child = test_table, + }, + { } +}; + +static struct ctl_table test_sysctl_root_table[] = { + { + .procname = "debug", + .maxlen = 0, + .mode = 0555, + .child = test_sysctl_table, + }, + { } +}; + +static struct ctl_table_header *test_sysctl_header; + +static int __init test_sysctl_init(void) +{ + test_sysctl_header = register_sysctl_table(test_sysctl_root_table); + if (!test_sysctl_header) + return -ENOMEM; + return 0; +} +late_initcall(test_sysctl_init); + +static void __exit test_sysctl_exit(void) +{ + if (test_sysctl_header) + unregister_sysctl_table(test_sysctl_header); +} + +module_exit(test_sysctl_exit); + +MODULE_AUTHOR("Luis R. Rodriguez <mcgrof@kernel.org>"); +MODULE_LICENSE("GPL"); |