#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/sched/signal.h>
#include <linux/sched/clock.h>
#include <linux/cpu.h>
#include <linux/nmi.h>
#include <linux/mm.h>
#include <linux/uaccess.h>
#include <linux/file.h>
static unsigned int time_secs;
module_param(time_secs, uint, 0600);
MODULE_PARM_DESC(time_secs, "lockup time in seconds, default 0");
static unsigned int time_nsecs;
module_param(time_nsecs, uint, 0600);
MODULE_PARM_DESC(time_nsecs, "nanoseconds part of lockup time, default 0");
static unsigned int cooldown_secs;
module_param(cooldown_secs, uint, 0600);
MODULE_PARM_DESC(cooldown_secs, "cooldown time between iterations in seconds, default 0");
static unsigned int cooldown_nsecs;
module_param(cooldown_nsecs, uint, 0600);
MODULE_PARM_DESC(cooldown_nsecs, "nanoseconds part of cooldown, default 0");
static unsigned int iterations = 1;
module_param(iterations, uint, 0600);
MODULE_PARM_DESC(iterations, "lockup iterations, default 1");
static bool all_cpus;
module_param(all_cpus, bool, 0400);
MODULE_PARM_DESC(all_cpus, "trigger lockup at all cpus at once");
static int wait_state;
static char *state = "R";
module_param(state, charp, 0400);
MODULE_PARM_DESC(state, "wait in 'R' running (default), 'D' uninterruptible, 'K' killable, 'S' interruptible state");
static bool use_hrtimer;
module_param(use_hrtimer, bool, 0400);
MODULE_PARM_DESC(use_hrtimer, "use high-resolution timer for sleeping");
static bool iowait;
module_param(iowait, bool, 0400);
MODULE_PARM_DESC(iowait, "account sleep time as iowait");
static bool lock_read;
module_param(lock_read, bool, 0400);
MODULE_PARM_DESC(lock_read, "lock read-write locks for read");
static bool lock_single;
module_param(lock_single, bool, 0400);
MODULE_PARM_DESC(lock_single, "acquire locks only at one cpu");
static bool reacquire_locks;
module_param(reacquire_locks, bool, 0400);
MODULE_PARM_DESC(reacquire_locks, "release and reacquire locks/irq/preempt between iterations");
static bool touch_softlockup;
module_param(touch_softlockup, bool, 0600);
MODULE_PARM_DESC(touch_softlockup, "touch soft-lockup watchdog between iterations");
static bool touch_hardlockup;
module_param(touch_hardlockup, bool, 0600);
MODULE_PARM_DESC(touch_hardlockup, "touch hard-lockup watchdog between iterations");
static bool call_cond_resched;
module_param(call_cond_resched, bool, 0600);
MODULE_PARM_DESC(call_cond_resched, "call cond_resched() between iterations");
static bool measure_lock_wait;
module_param(measure_lock_wait, bool, 0400);
MODULE_PARM_DESC(measure_lock_wait, "measure lock wait time");
static unsigned long lock_wait_threshold = ULONG_MAX;
module_param(lock_wait_threshold, ulong, 0400);
MODULE_PARM_DESC(lock_wait_threshold, "print lock wait time longer than this in nanoseconds, default off");
static bool test_disable_irq;
module_param_named(disable_irq, test_disable_irq, bool, 0400);
MODULE_PARM_DESC(disable_irq, "disable interrupts: generate hard-lockups");
static bool disable_softirq;
module_param(disable_softirq, bool, 0400);
MODULE_PARM_DESC(disable_softirq, "disable bottom-half irq handlers");
static bool disable_preempt;
module_param(disable_preempt, bool, 0400);
MODULE_PARM_DESC(disable_preempt, "disable preemption: generate soft-lockups");
static bool lock_rcu;
module_param(lock_rcu, bool, 0400);
MODULE_PARM_DESC(lock_rcu, "grab rcu_read_lock: generate rcu stalls");
static bool lock_mmap_sem;
module_param(lock_mmap_sem, bool, 0400);
MODULE_PARM_DESC(lock_mmap_sem, "lock mm->mmap_lock: block procfs interfaces");
static unsigned long lock_rwsem_ptr;
module_param_unsafe(lock_rwsem_ptr, ulong, 0400);
MODULE_PARM_DESC(lock_rwsem_ptr, "lock rw_semaphore at address");
static unsigned long lock_mutex_ptr;
module_param_unsafe(lock_mutex_ptr, ulong, 0400);
MODULE_PARM_DESC(lock_mutex_ptr, "lock mutex at address");
static unsigned long lock_spinlock_ptr;
module_param_unsafe(lock_spinlock_ptr, ulong, 0400);
MODULE_PARM_DESC(lock_spinlock_ptr, "lock spinlock at address");
static unsigned long lock_rwlock_ptr;
module_param_unsafe(lock_rwlock_ptr, ulong, 0400);
MODULE_PARM_DESC(lock_rwlock_ptr, "lock rwlock at address");
static unsigned int alloc_pages_nr;
module_param_unsafe(alloc_pages_nr, uint, 0600);
MODULE_PARM_DESC(alloc_pages_nr, "allocate and free pages under locks");
static unsigned int alloc_pages_order;
module_param(alloc_pages_order, uint, 0400);
MODULE_PARM_DESC(alloc_pages_order, "page order to allocate");
static gfp_t alloc_pages_gfp = GFP_KERNEL;
module_param_unsafe(alloc_pages_gfp, uint, 0400);
MODULE_PARM_DESC(alloc_pages_gfp, "allocate pages with this gfp_mask, default GFP_KERNEL");
static bool alloc_pages_atomic;
module_param(alloc_pages_atomic, bool, 0400);
MODULE_PARM_DESC(alloc_pages_atomic, "allocate pages with GFP_ATOMIC");
static bool reallocate_pages;
module_param(reallocate_pages, bool, 0400);
MODULE_PARM_DESC(reallocate_pages, "free and allocate pages between iterations");
struct file *test_file;
static struct inode *test_inode;
static char test_file_path[256];
module_param_string(file_path, test_file_path, sizeof(test_file_path), 0400);
MODULE_PARM_DESC(file_path, "file path to test");
static bool test_lock_inode;
module_param_named(lock_inode, test_lock_inode, bool, 0400);
MODULE_PARM_DESC(lock_inode, "lock file -> inode -> i_rwsem");
static bool test_lock_mapping;
module_param_named(lock_mapping, test_lock_mapping, bool, 0400);
MODULE_PARM_DESC(lock_mapping, "lock file -> mapping -> i_mmap_rwsem");
static bool test_lock_sb_umount;
module_param_named(lock_sb_umount, test_lock_sb_umount, bool, 0400);
MODULE_PARM_DESC(lock_sb_umount, "lock file -> sb -> s_umount");
static atomic_t alloc_pages_failed = ATOMIC_INIT(0);
static atomic64_t max_lock_wait = ATOMIC64_INIT(0);
static struct task_struct *main_task;
static int master_cpu;
static void test_lock(bool master, bool verbose)
{
u64 wait_start;
if (measure_lock_wait)
wait_start = local_clock();
if (lock_mutex_ptr && master) {
if (verbose)
pr_notice("lock mutex %ps\n", (void *)lock_mutex_ptr);
mutex_lock((struct mutex *)lock_mutex_ptr);
}
if (lock_rwsem_ptr && master) {
if (verbose)
pr_notice("lock rw_semaphore %ps\n",
(void *)lock_rwsem_ptr);
if (lock_read)
down_read((struct rw_semaphore *)lock_rwsem_ptr);
else
down_write((struct rw_semaphore *)lock_rwsem_ptr);
}
if (lock_mmap_sem && master) {
if (verbose)
pr_notice("lock mmap_lock pid=%d\n", main_task->pid);
if (lock_read)
mmap_read_lock(main_task->mm);
else
mmap_write_lock(main_task->mm);
}
if (test_disable_irq)
local_irq_disable();
if (disable_softirq)
local_bh_disable();
if (disable_preempt)
preempt_disable();
if (lock_rcu)
rcu_read_lock();
if (lock_spinlock_ptr && master) {
if (verbose)
pr_notice("lock spinlock %ps\n",
(void *)lock_spinlock_ptr);
spin_lock((spinlock_t *)lock_spinlock_ptr);
}
if (lock_rwlock_ptr && master) {
if (verbose)
pr_notice("lock rwlock %ps\n",
(void *)lock_rwlock_ptr);
if (lock_read)
read_lock((rwlock_t *)lock_rwlock_ptr);
else
write_lock((rwlock_t *)lock_rwlock_ptr);
}
if (measure_lock_wait) {
s64 cur_wait = local_clock() - wait_start;
s64 max_wait = atomic64_read(&max_lock_wait);
do {
if (cur_wait < max_wait)
break;
max_wait = atomic64_cmpxchg(&max_lock_wait,
max_wait, cur_wait);
} while (max_wait != cur_wait);
if (cur_wait > lock_wait_threshold)
pr_notice_ratelimited("lock wait %lld ns\n", cur_wait);
}
}
static void test_unlock(bool master, bool verbose)
{
if (lock_rwlock_ptr && master) {
if (lock_read)
read_unlock((rwlock_t *)lock_rwlock_ptr);
else
write_unlock((rwlock_t *)lock_rwlock_ptr);
if (verbose)
pr_notice("unlock rwlock %ps\n",
(void *)lock_rwlock_ptr);
}
if (lock_spinlock_ptr && master) {
spin_unlock((spinlock_t *)lock_spinlock_ptr);
if (verbose)
pr_notice("unlock spinlock %ps\n",
(void *)lock_spinlock_ptr);
}
if (lock_rcu)
rcu_read_unlock();
if (disable_preempt)
preempt_enable();
if (disable_softirq)
local_bh_enable();
if (test_disable_irq)
local_irq_enable();
if (lock_mmap_sem && master) {
if (lock_read)
mmap_read_unlock(main_task->mm);
else
mmap_write_unlock(main_task->mm);
if (verbose)
pr_notice("unlock mmap_lock pid=%d\n", main_task->pid);
}
if (lock_rwsem_ptr && master) {
if (lock_read)
up_read((struct rw_semaphore *)lock_rwsem_ptr);
else
up_write((struct rw_semaphore *)lock_rwsem_ptr);
if (verbose)
pr_notice("unlock rw_semaphore %ps\n",
(void *)lock_rwsem_ptr);
}
if (lock_mutex_ptr && master) {
mutex_unlock((struct mutex *)lock_mutex_ptr);
if (verbose)
pr_notice("unlock mutex %ps\n",
(void *)lock_mutex_ptr);
}
}
static void test_alloc_pages(struct list_head *pages)
{
struct page *page;
unsigned int i;
for (i = 0; i < alloc_pages_nr; i++) {
page = alloc_pages(alloc_pages_gfp, alloc_pages_order);
if (!page) {
atomic_inc(&alloc_pages_failed);
break;
}
list_add(&page->lru, pages);
}
}
static void test_free_pages(struct list_head *pages)
{
struct page *page, *next;
list_for_each_entry_safe(page, next, pages, lru)
__free_pages(page, alloc_pages_order);
INIT_LIST_HEAD(pages);
}
static void test_wait(unsigned int secs, unsigned int nsecs)
{
if (wait_state == TASK_RUNNING) {
if (secs)
mdelay(secs * MSEC_PER_SEC);
if (nsecs)
ndelay(nsecs);
return;
}
__set_current_state(wait_state);
if (use_hrtimer) {
ktime_t time;
time = ns_to_ktime((u64)secs * NSEC_PER_SEC + nsecs);
schedule_hrtimeout(&time, HRTIMER_MODE_REL);
} else {
schedule_timeout(secs * HZ + nsecs_to_jiffies(nsecs));
}
}
static void test_lockup(bool master)
{
u64 lockup_start = local_clock();
unsigned int iter = 0;
LIST_HEAD(pages);
pr_notice("Start on CPU%d\n", raw_smp_processor_id());
test_lock(master, true);
test_alloc_pages(&pages);
while (iter++ < iterations && !signal_pending(main_task)) {
if (iowait)
current->in_iowait = 1;
test_wait(time_secs, time_nsecs);
if (iowait)
current->in_iowait = 0;
if (reallocate_pages)
test_free_pages(&pages);
if (reacquire_locks)
test_unlock(master, false);
if (touch_softlockup)
touch_softlockup_watchdog();
if (touch_hardlockup)
touch_nmi_watchdog();
if (call_cond_resched)
cond_resched();
test_wait(cooldown_secs, cooldown_nsecs);
if (reacquire_locks)
test_lock(master, false);
if (reallocate_pages)
test_alloc_pages(&pages);
}
pr_notice("Finish on CPU%d in %lld ns\n", raw_smp_processor_id(),
local_clock() - lockup_start);
test_free_pages(&pages);
test_unlock(master, true);
}
static DEFINE_PER_CPU(struct work_struct, test_works);
static void test_work_fn(struct work_struct *work)
{
test_lockup(!lock_single ||
work == per_cpu_ptr(&test_works, master_cpu));
}
static bool test_kernel_ptr(unsigned long addr, int size)
{
void *ptr = (void *)addr;
char buf;
if (!addr)
return false;
if (!IS_ENABLED(CONFIG_ALTERNATE_USER_ADDRESS_SPACE) &&
(access_ok((void __user *)ptr, 1) ||
access_ok((void __user *)ptr + size - 1, 1))) {
pr_err("user space ptr invalid in kernel: %#lx\n", addr);
return true;
}
if (get_kernel_nofault(buf, ptr) ||
get_kernel_nofault(buf, ptr + size - 1)) {
pr_err("invalid kernel ptr: %#lx\n", addr);
return true;
}
return false;
}
static bool __maybe_unused test_magic(unsigned long addr, int offset,
unsigned int expected)
{
void *ptr = (void *)addr + offset;
unsigned int magic = 0;
if (!addr)
return false;
if (get_kernel_nofault(magic, ptr) || magic != expected) {
pr_err("invalid magic at %#lx + %#x = %#x, expected %#x\n",
addr, offset, magic, expected);
return true;
}
return false;
}
static int __init test_lockup_init(void)
{
u64 test_start = local_clock();
main_task = current;
switch (state[0]) {
case 'S':
wait_state = TASK_INTERRUPTIBLE;
break;
case 'D':
wait_state = TASK_UNINTERRUPTIBLE;
break;
case 'K':
wait_state = TASK_KILLABLE;
break;
case 'R':
wait_state = TASK_RUNNING;
break;
default:
pr_err("unknown state=%s\n", state);
return -EINVAL;
}
if (alloc_pages_atomic)
alloc_pages_gfp = GFP_ATOMIC;
if (test_kernel_ptr(lock_spinlock_ptr, sizeof(spinlock_t)) ||
test_kernel_ptr(lock_rwlock_ptr, sizeof(rwlock_t)) ||
test_kernel_ptr(lock_mutex_ptr, sizeof(struct mutex)) ||
test_kernel_ptr(lock_rwsem_ptr, sizeof(struct rw_semaphore)))
return -EINVAL;
#ifdef CONFIG_DEBUG_SPINLOCK
#ifdef CONFIG_PREEMPT_RT
if (test_magic(lock_spinlock_ptr,
offsetof(spinlock_t, lock.wait_lock.magic),
SPINLOCK_MAGIC) ||
test_magic(lock_rwlock_ptr,
offsetof(rwlock_t, rwbase.rtmutex.wait_lock.magic),
SPINLOCK_MAGIC) ||
test_magic(lock_mutex_ptr,
offsetof(struct mutex, rtmutex.wait_lock.magic),
SPINLOCK_MAGIC) ||
test_magic(lock_rwsem_ptr,
offsetof(struct rw_semaphore, rwbase.rtmutex.wait_lock.magic),
SPINLOCK_MAGIC))
return -EINVAL;
#else
if (test_magic(lock_spinlock_ptr,
offsetof(spinlock_t, rlock.magic),
SPINLOCK_MAGIC) ||
test_magic(lock_rwlock_ptr,
offsetof(rwlock_t, magic),
RWLOCK_MAGIC) ||
test_magic(lock_mutex_ptr,
offsetof(struct mutex, wait_lock.magic),
SPINLOCK_MAGIC) ||
test_magic(lock_rwsem_ptr,
offsetof(struct rw_semaphore, wait_lock.magic),
SPINLOCK_MAGIC))
return -EINVAL;
#endif
#endif
if ((wait_state != TASK_RUNNING ||
(call_cond_resched && !reacquire_locks) ||
(alloc_pages_nr && gfpflags_allow_blocking(alloc_pages_gfp))) &&
(test_disable_irq || disable_softirq || disable_preempt ||
lock_rcu || lock_spinlock_ptr || lock_rwlock_ptr)) {
pr_err("refuse to sleep in atomic context\n");
return -EINVAL;
}
if (lock_mmap_sem && !main_task->mm) {
pr_err("no mm to lock mmap_lock\n");
return -EINVAL;
}
if (test_file_path[0]) {
test_file = filp_open(test_file_path, O_RDONLY, 0);
if (IS_ERR(test_file)) {
pr_err("failed to open %s: %ld\n", test_file_path, PTR_ERR(test_file));
return PTR_ERR(test_file);
}
test_inode = file_inode(test_file);
} else if (test_lock_inode ||
test_lock_mapping ||
test_lock_sb_umount) {
pr_err("no file to lock\n");
return -EINVAL;
}
if (test_lock_inode && test_inode)
lock_rwsem_ptr = (unsigned long)&test_inode->i_rwsem;
if (test_lock_mapping && test_file && test_file->f_mapping)
lock_rwsem_ptr = (unsigned long)&test_file->f_mapping->i_mmap_rwsem;
if (test_lock_sb_umount && test_inode)
lock_rwsem_ptr = (unsigned long)&test_inode->i_sb->s_umount;
pr_notice("START pid=%d time=%u +%u ns cooldown=%u +%u ns iterations=%u state=%s %s%s%s%s%s%s%s%s%s%s%s\n",
main_task->pid, time_secs, time_nsecs,
cooldown_secs, cooldown_nsecs, iterations, state,
all_cpus ? "all_cpus " : "",
iowait ? "iowait " : "",
test_disable_irq ? "disable_irq " : "",
disable_softirq ? "disable_softirq " : "",
disable_preempt ? "disable_preempt " : "",
lock_rcu ? "lock_rcu " : "",
lock_read ? "lock_read " : "",
touch_softlockup ? "touch_softlockup " : "",
touch_hardlockup ? "touch_hardlockup " : "",
call_cond_resched ? "call_cond_resched " : "",
reacquire_locks ? "reacquire_locks " : "");
if (alloc_pages_nr)
pr_notice("ALLOCATE PAGES nr=%u order=%u gfp=%pGg %s\n",
alloc_pages_nr, alloc_pages_order, &alloc_pages_gfp,
reallocate_pages ? "reallocate_pages " : "");
if (all_cpus) {
unsigned int cpu;
cpus_read_lock();
preempt_disable();
master_cpu = smp_processor_id();
for_each_online_cpu(cpu) {
INIT_WORK(per_cpu_ptr(&test_works, cpu), test_work_fn);
queue_work_on(cpu, system_highpri_wq,
per_cpu_ptr(&test_works, cpu));
}
preempt_enable();
for_each_online_cpu(cpu)
flush_work(per_cpu_ptr(&test_works, cpu));
cpus_read_unlock();
} else {
test_lockup(true);
}
if (measure_lock_wait)
pr_notice("Maximum lock wait: %lld ns\n",
atomic64_read(&max_lock_wait));
if (alloc_pages_nr)
pr_notice("Page allocation failed %u times\n",
atomic_read(&alloc_pages_failed));
pr_notice("FINISH in %llu ns\n", local_clock() - test_start);
if (test_file)
fput(test_file);
if (signal_pending(main_task))
return -EINTR;
return -EAGAIN;
}
module_init(test_lockup_init);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Konstantin Khlebnikov <khlebnikov@yandex-team.ru>");
MODULE_DESCRIPTION("Test module to generate lockups");
