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// SPDX-License-Identifier: GPL-2.0/* * Test module to generate lockups */#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; 	/* should be at least readable kernel address */	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))

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