[lttng-modules.git] / lttng-statedump-impl.c

/*
 * Linux Trace Toolkit Next Generation Kernel State Dump
 *
 * Copyright 2005 Jean-Hugues Deschenes <jean-hugues.deschenes@polymtl.ca>
 * Copyright 2006-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * Changes:
 *	Eric Clement:                   Add listing of network IP interface
 *	2006, 2007 Mathieu Desnoyers	Fix kernel threads
 *	                                Various updates
 *
 * Dual LGPL v2.1/GPL v2 license.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/netlink.h>
#include <linux/inet.h>
#include <linux/ip.h>
#include <linux/kthread.h>
#include <linux/proc_fs.h>
#include <linux/file.h>
#include <linux/interrupt.h>
#include <linux/irqnr.h>
#include <linux/cpu.h>
#include <linux/netdevice.h>
#include <linux/inetdevice.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/fdtable.h>
#include <linux/swap.h>
#include <linux/wait.h>
#include <linux/mutex.h>

#include "lttng-events.h"
#include "wrapper/irqdesc.h"

#ifdef CONFIG_GENERIC_HARDIRQS
#include <linux/irq.h>
#endif

/* Define the tracepoints, but do not build the probes */
#define CREATE_TRACE_POINTS
#define TRACE_INCLUDE_PATH ../instrumentation/events/lttng-module
#define TRACE_INCLUDE_FILE lttng-statedump
#include "instrumentation/events/lttng-module/lttng-statedump.h"

/*
 * Protected by the trace lock.
 */
static struct delayed_work cpu_work[NR_CPUS];
static DECLARE_WAIT_QUEUE_HEAD(statedump_wq);
static atomic_t kernel_threads_to_run;

enum lttng_thread_type {
	LTTNG_USER_THREAD = 0,
	LTTNG_KERNEL_THREAD = 1,
};

enum lttng_execution_mode {
	LTTNG_USER_MODE = 0,
	LTTNG_SYSCALL = 1,
	LTTNG_TRAP = 2,
	LTTNG_IRQ = 3,
	LTTNG_SOFTIRQ = 4,
	LTTNG_MODE_UNKNOWN = 5,
};

enum lttng_execution_submode {
	LTTNG_NONE = 0,
	LTTNG_UNKNOWN = 1,
};

enum lttng_process_status {
	LTTNG_UNNAMED = 0,
	LTTNG_WAIT_FORK = 1,
	LTTNG_WAIT_CPU = 2,
	LTTNG_EXIT = 3,
	LTTNG_ZOMBIE = 4,
	LTTNG_WAIT = 5,
	LTTNG_RUN = 6,
	LTTNG_DEAD = 7,
};

#ifdef CONFIG_INET
static
void lttng_enumerate_device(struct lttng_session *session,
		struct net_device *dev)
{
	struct in_device *in_dev;
	struct in_ifaddr *ifa;

	if (dev->flags & IFF_UP) {
		in_dev = in_dev_get(dev);
		if (in_dev) {
			for (ifa = in_dev->ifa_list; ifa != NULL;
			     ifa = ifa->ifa_next) {
				trace_lttng_statedump_network_interface(
					session, dev, ifa);
			}
			in_dev_put(in_dev);
		}
	} else {
		trace_lttng_statedump_network_interface(
			session, dev, NULL);
	}
}

static
int lttng_enumerate_network_ip_interface(struct lttng_session *session)
{
	struct net_device *dev;

	read_lock(&dev_base_lock);
	for_each_netdev(&init_net, dev)
		lttng_enumerate_device(session, dev);
	read_unlock(&dev_base_lock);

	return 0;
}
#else /* CONFIG_INET */
static inline
int lttng_enumerate_network_ip_interface(struct lttng_session *session)
{
	return 0;
}
#endif /* CONFIG_INET */


static
void lttng_enumerate_task_fd(struct lttng_session *session,
		struct task_struct *p, char *tmp)
{
	struct fdtable *fdt;
	struct file *filp;
	unsigned int i;
	const unsigned char *path;

	task_lock(p);
	if (!p->files)
		goto unlock_task;
	spin_lock(&p->files->file_lock);
	fdt = files_fdtable(p->files);
	for (i = 0; i < fdt->max_fds; i++) {
		filp = fcheck_files(p->files, i);
		if (!filp)
			continue;
		path = d_path(&filp->f_path, tmp, PAGE_SIZE);
		/* Make sure we give at least some info */
		trace_lttng_statedump_file_descriptor(session, p, i,
			IS_ERR(path) ?
				filp->f_dentry->d_name.name :
				path);
	}
	spin_unlock(&p->files->file_lock);
unlock_task:
	task_unlock(p);
}

static
int lttng_enumerate_file_descriptors(struct lttng_session *session)
{
	struct task_struct *p;
	char *tmp = (char *) __get_free_page(GFP_KERNEL);

	/* Enumerate active file descriptors */
	rcu_read_lock();
	for_each_process(p)
		lttng_enumerate_task_fd(session, p, tmp);
	rcu_read_unlock();
	free_page((unsigned long) tmp);
	return 0;
}

static
void lttng_enumerate_task_vm_maps(struct lttng_session *session,
		struct task_struct *p)
{
	struct mm_struct *mm;
	struct vm_area_struct *map;
	unsigned long ino;

	/* get_task_mm does a task_lock... */
	mm = get_task_mm(p);
	if (!mm)
		return;

	map = mm->mmap;
	if (map) {
		down_read(&mm->mmap_sem);
		while (map) {
			if (map->vm_file)
				ino = map->vm_file->f_dentry->d_inode->i_ino;
			else
				ino = 0;
			trace_lttng_statedump_vm_map(session, p, map, ino);
			map = map->vm_next;
		}
		up_read(&mm->mmap_sem);
	}
	mmput(mm);
}

static
int lttng_enumerate_vm_maps(struct lttng_session *session)
{
	struct task_struct *p;

	rcu_read_lock();
	for_each_process(p)
		lttng_enumerate_task_vm_maps(session, p);
	rcu_read_unlock();
	return 0;
}

#ifdef CONFIG_GENERIC_HARDIRQS
static
void lttng_list_interrupts(struct lttng_session *session)
{
	unsigned int irq;
	unsigned long flags = 0;
	struct irq_desc *desc;

#define irq_to_desc	wrapper_irq_to_desc
	/* needs irq_desc */
	for_each_irq_desc(irq, desc) {
		struct irqaction *action;
		const char *irq_chip_name =
			irq_desc_get_chip(desc)->name ? : "unnamed_irq_chip";

		local_irq_save(flags);
		raw_spin_lock(&desc->lock);
		for (action = desc->action; action; action = action->next) {
			trace_lttng_statedump_interrupt(session,
				irq, irq_chip_name, action);
		}
		raw_spin_unlock(&desc->lock);
		local_irq_restore(flags);
	}
#undef irq_to_desc
}
#else
static inline
void list_interrupts(struct lttng_session *session)
{
}
#endif

static
int lttng_enumerate_process_states(struct lttng_session *session)
{
	struct task_struct *g, *p;

	rcu_read_lock();
	for_each_process(g) {
		p = g;
		do {
			enum lttng_execution_mode mode =
				LTTNG_MODE_UNKNOWN;
			enum lttng_execution_submode submode =
				LTTNG_UNKNOWN;
			enum lttng_process_status status;
			enum lttng_thread_type type;

			task_lock(p);
			if (p->exit_state == EXIT_ZOMBIE)
				status = LTTNG_ZOMBIE;
			else if (p->exit_state == EXIT_DEAD)
				status = LTTNG_DEAD;
			else if (p->state == TASK_RUNNING) {
				/* Is this a forked child that has not run yet? */
				if (list_empty(&p->rt.run_list))
					status = LTTNG_WAIT_FORK;
				else
					/*
					 * All tasks are considered as wait_cpu;
					 * the viewer will sort out if the task
					 * was really running at this time.
					 */
					status = LTTNG_WAIT_CPU;
			} else if (p->state &
				(TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)) {
				/* Task is waiting for something to complete */
				status = LTTNG_WAIT;
			} else
				status = LTTNG_UNNAMED;
			submode = LTTNG_NONE;

			/*
			 * Verification of t->mm is to filter out kernel
			 * threads; Viewer will further filter out if a
			 * user-space thread was in syscall mode or not.
			 */
			if (p->mm)
				type = LTTNG_USER_THREAD;
			else
				type = LTTNG_KERNEL_THREAD;
			trace_lttng_statedump_process_state(session,
				p, type, mode, submode, status);
			task_unlock(p);
		} while_each_thread(g, p);
	}
	rcu_read_unlock();

	return 0;
}

static
void lttng_statedump_work_func(struct work_struct *work)
{
	if (atomic_dec_and_test(&kernel_threads_to_run))
		/* If we are the last thread, wake up do_lttng_statedump */
		wake_up(&statedump_wq);
}

static
int do_lttng_statedump(struct lttng_session *session)
{
	int cpu;

	printk(KERN_DEBUG "LTT state dump thread start\n");
	trace_lttng_statedump_start(session);
	lttng_enumerate_process_states(session);
	lttng_enumerate_file_descriptors(session);
	lttng_enumerate_vm_maps(session);
	lttng_list_interrupts(session);
	lttng_enumerate_network_ip_interface(session);

	/* TODO lttng_dump_idt_table(session); */
	/* TODO lttng_dump_softirq_vec(session); */
	/* TODO lttng_list_modules(session); */
	/* TODO lttng_dump_swap_files(session); */

	/*
	 * Fire off a work queue on each CPU. Their sole purpose in life
	 * is to guarantee that each CPU has been in a state where is was in
	 * syscall mode (i.e. not in a trap, an IRQ or a soft IRQ).
	 */
	get_online_cpus();
	atomic_set(&kernel_threads_to_run, num_online_cpus());
	for_each_online_cpu(cpu) {
		INIT_DELAYED_WORK(&cpu_work[cpu], lttng_statedump_work_func);
		schedule_delayed_work_on(cpu, &cpu_work[cpu], 0);
	}
	/* Wait for all threads to run */
	__wait_event(statedump_wq, (atomic_read(&kernel_threads_to_run) != 0));
	put_online_cpus();
	/* Our work is done */
	printk(KERN_DEBUG "LTT state dump end\n");
	trace_lttng_statedump_end(session);
	return 0;
}

/*
 * Called with session mutex held.
 */
int lttng_statedump_start(struct lttng_session *session)
{
	printk(KERN_DEBUG "LTTng: state dump begin\n");
	return do_lttng_statedump(session);
}
EXPORT_SYMBOL_GPL(lttng_statedump_start);

MODULE_LICENSE("GPL and additional rights");
MODULE_AUTHOR("Jean-Hugues Deschenes");
MODULE_DESCRIPTION("Linux Trace Toolkit Next Generation Statedump");
Commit	Line	Data
c337ddc2 MD	1	/*
	2	* Linux Trace Toolkit Next Generation Kernel State Dump
	3	*
	4	* Copyright 2005 Jean-Hugues Deschenes <jean-hugues.deschenes@polymtl.ca>
	5	* Copyright 2006-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	6	*
	7	* Changes:
	8	* Eric Clement: Add listing of network IP interface
	9	* 2006, 2007 Mathieu Desnoyers Fix kernel threads
	10	* Various updates
	11	*
	12	* Dual LGPL v2.1/GPL v2 license.
	13	*/
	14
	15	#include <linux/init.h>
	16	#include <linux/module.h>
	17	#include <linux/netlink.h>
	18	#include <linux/inet.h>
	19	#include <linux/ip.h>
	20	#include <linux/kthread.h>
	21	#include <linux/proc_fs.h>
	22	#include <linux/file.h>
	23	#include <linux/interrupt.h>
	24	#include <linux/irqnr.h>
	25	#include <linux/cpu.h>
	26	#include <linux/netdevice.h>
	27	#include <linux/inetdevice.h>
	28	#include <linux/sched.h>
	29	#include <linux/mm.h>
	30	#include <linux/fdtable.h>
	31	#include <linux/swap.h>
	32	#include <linux/wait.h>
	33	#include <linux/mutex.h>
	34
	35	#include "lttng-events.h"
	36	#include "wrapper/irqdesc.h"
	37
	38	#ifdef CONFIG_GENERIC_HARDIRQS
	39	#include <linux/irq.h>
	40	#endif
	41
	42	/* Define the tracepoints, but do not build the probes */
	43	#define CREATE_TRACE_POINTS
	44	#define TRACE_INCLUDE_PATH ../instrumentation/events/lttng-module
	45	#define TRACE_INCLUDE_FILE lttng-statedump
	46	#include "instrumentation/events/lttng-module/lttng-statedump.h"
	47
	48	/*
	49	* Protected by the trace lock.
	50	*/
	51	static struct delayed_work cpu_work[NR_CPUS];
	52	static DECLARE_WAIT_QUEUE_HEAD(statedump_wq);
	53	static atomic_t kernel_threads_to_run;
	54
	55	enum lttng_thread_type {
	56	LTTNG_USER_THREAD = 0,
	57	LTTNG_KERNEL_THREAD = 1,
	58	};
	59
	60	enum lttng_execution_mode {
	61	LTTNG_USER_MODE = 0,
	62	LTTNG_SYSCALL = 1,
	63	LTTNG_TRAP = 2,
	64	LTTNG_IRQ = 3,
65	LTTNG_SOFTIRQ = 4,
66	LTTNG_MODE_UNKNOWN = 5,
67	};
68
69	enum lttng_execution_submode {
70	LTTNG_NONE = 0,
71	LTTNG_UNKNOWN = 1,
72	};
73
74	enum lttng_process_status {
75	LTTNG_UNNAMED = 0,
76	LTTNG_WAIT_FORK = 1,
77	LTTNG_WAIT_CPU = 2,
78	LTTNG_EXIT = 3,
79	LTTNG_ZOMBIE = 4,
80	LTTNG_WAIT = 5,
81	LTTNG_RUN = 6,
82	LTTNG_DEAD = 7,
83	};
84
85	#ifdef CONFIG_INET
86	static
87	void lttng_enumerate_device(struct lttng_session *session,
88	struct net_device *dev)
89	{
90	struct in_device *in_dev;
91	struct in_ifaddr *ifa;
92
93	if (dev->flags & IFF_UP) {
94	in_dev = in_dev_get(dev);
95	if (in_dev) {
96	for (ifa = in_dev->ifa_list; ifa != NULL;
97	ifa = ifa->ifa_next) {
98	trace_lttng_statedump_network_interface(
99	session, dev, ifa);
100	}
101	in_dev_put(in_dev);
102	}
103	} else {
104	trace_lttng_statedump_network_interface(
105	session, dev, NULL);
106	}
107	}
108
109	static
110	int lttng_enumerate_network_ip_interface(struct lttng_session *session)
111	{
112	struct net_device *dev;
113
114	read_lock(&dev_base_lock);
115	for_each_netdev(&init_net, dev)
116	lttng_enumerate_device(session, dev);
117	read_unlock(&dev_base_lock);
118
119	return 0;
120	}
121	#else /* CONFIG_INET */
122	static inline
123	int lttng_enumerate_network_ip_interface(struct lttng_session *session)
124	{
125	return 0;
126	}
127	#endif /* CONFIG_INET */
128
129
130	static
131	void lttng_enumerate_task_fd(struct lttng_session *session,
132	struct task_struct p, char tmp)
133	{
134	struct fdtable *fdt;
135	struct file *filp;
136	unsigned int i;
137	const unsigned char *path;
138
139	task_lock(p);
140	if (!p->files)
141	goto unlock_task;
142	spin_lock(&p->files->file_lock);
143	fdt = files_fdtable(p->files);
144	for (i = 0; i < fdt->max_fds; i++) {
145	filp = fcheck_files(p->files, i);
146	if (!filp)
147	continue;
148	path = d_path(&filp->f_path, tmp, PAGE_SIZE);
149	/* Make sure we give at least some info */
150	trace_lttng_statedump_file_descriptor(session, p, i,
151	IS_ERR(path) ?
152	filp->f_dentry->d_name.name :
153	path);
154	}
155	spin_unlock(&p->files->file_lock);
156	unlock_task:
157	task_unlock(p);
158	}
159
160	static
161	int lttng_enumerate_file_descriptors(struct lttng_session *session)
162	{
163	struct task_struct *p;
164	char tmp = (char ) __get_free_page(GFP_KERNEL);
165
166	/* Enumerate active file descriptors */
167	rcu_read_lock();
168	for_each_process(p)
169	lttng_enumerate_task_fd(session, p, tmp);
170	rcu_read_unlock();
171	free_page((unsigned long) tmp);
172	return 0;
173	}
174
175	static
176	void lttng_enumerate_task_vm_maps(struct lttng_session *session,
177	struct task_struct *p)
178	{
179	struct mm_struct *mm;
180	struct vm_area_struct *map;
181	unsigned long ino;
182
183	/* get_task_mm does a task_lock... */
184	mm = get_task_mm(p);
185	if (!mm)
186	return;
187
188	map = mm->mmap;
189	if (map) {
190	down_read(&mm->mmap_sem);
191	while (map) {
192	if (map->vm_file)
193	ino = map->vm_file->f_dentry->d_inode->i_ino;
194	else
195	ino = 0;
196	trace_lttng_statedump_vm_map(session, p, map, ino);
197	map = map->vm_next;
198	}
199	up_read(&mm->mmap_sem);
200	}
201	mmput(mm);
202	}
203
204	static
205	int lttng_enumerate_vm_maps(struct lttng_session *session)
206	{
207	struct task_struct *p;
208
209	rcu_read_lock();
210	for_each_process(p)
211	lttng_enumerate_task_vm_maps(session, p);
212	rcu_read_unlock();
213	return 0;
214	}
215
216	#ifdef CONFIG_GENERIC_HARDIRQS
217	static
218	void lttng_list_interrupts(struct lttng_session *session)
219	{
220	unsigned int irq;
221	unsigned long flags = 0;
222	struct irq_desc *desc;
223
224	#define irq_to_desc wrapper_irq_to_desc
225	/* needs irq_desc */
226	for_each_irq_desc(irq, desc) {
227	struct irqaction *action;
228	const char *irq_chip_name =
229	irq_desc_get_chip(desc)->name ? : "unnamed_irq_chip";
230
231	local_irq_save(flags);
232	raw_spin_lock(&desc->lock);
233	for (action = desc->action; action; action = action->next) {
234	trace_lttng_statedump_interrupt(session,
235	irq, irq_chip_name, action);
236	}
237	raw_spin_unlock(&desc->lock);
238	local_irq_restore(flags);
239	}
240	#undef irq_to_desc
241	}
242	#else
243	static inline
244	void list_interrupts(struct lttng_session *session)
245	{
246	}
247	#endif
248
249	static
250	int lttng_enumerate_process_states(struct lttng_session *session)
251	{
252	struct task_struct g, p;
253
254	rcu_read_lock();
255	for_each_process(g) {
256	p = g;
257	do {
258	enum lttng_execution_mode mode =
259	LTTNG_MODE_UNKNOWN;
260	enum lttng_execution_submode submode =
261	LTTNG_UNKNOWN;
262	enum lttng_process_status status;
263	enum lttng_thread_type type;
264
265	task_lock(p);
266	if (p->exit_state == EXIT_ZOMBIE)
267	status = LTTNG_ZOMBIE;
268	else if (p->exit_state == EXIT_DEAD)
269	status = LTTNG_DEAD;
270	else if (p->state == TASK_RUNNING) {
271	/* Is this a forked child that has not run yet? */
272	if (list_empty(&p->rt.run_list))
273	status = LTTNG_WAIT_FORK;
274	else
275	/*
276	* All tasks are considered as wait_cpu;
277	* the viewer will sort out if the task
278	* was really running at this time.
279	*/
280	status = LTTNG_WAIT_CPU;
281	} else if (p->state &
282	(TASK_INTERRUPTIBLE \| TASK_UNINTERRUPTIBLE)) {
283	/* Task is waiting for something to complete */
284	status = LTTNG_WAIT;
285	} else
286	status = LTTNG_UNNAMED;
287	submode = LTTNG_NONE;
288
289	/*
290	* Verification of t->mm is to filter out kernel
291	* threads; Viewer will further filter out if a
292	* user-space thread was in syscall mode or not.
293	*/
294	if (p->mm)
295	type = LTTNG_USER_THREAD;
296	else
297	type = LTTNG_KERNEL_THREAD;
298	trace_lttng_statedump_process_state(session,
299	p, type, mode, submode, status);
300	task_unlock(p);
301	} while_each_thread(g, p);
302	}
303	rcu_read_unlock();
304
305	return 0;
306	}
307
308	static
309	void lttng_statedump_work_func(struct work_struct *work)
310	{
311	if (atomic_dec_and_test(&kernel_threads_to_run))
312	/* If we are the last thread, wake up do_lttng_statedump */
313	wake_up(&statedump_wq);
314	}
315
316	static
317	int do_lttng_statedump(struct lttng_session *session)
318	{
319	int cpu;
320
321	printk(KERN_DEBUG "LTT state dump thread start\n");
322	trace_lttng_statedump_start(session);
323	lttng_enumerate_process_states(session);
324	lttng_enumerate_file_descriptors(session);
325	lttng_enumerate_vm_maps(session);
326	lttng_list_interrupts(session);
327	lttng_enumerate_network_ip_interface(session);
328
329	/* TODO lttng_dump_idt_table(session); */
330	/* TODO lttng_dump_softirq_vec(session); */
331	/* TODO lttng_list_modules(session); */
332	/* TODO lttng_dump_swap_files(session); */
333
334	/*
335	* Fire off a work queue on each CPU. Their sole purpose in life
336	* is to guarantee that each CPU has been in a state where is was in
337	* syscall mode (i.e. not in a trap, an IRQ or a soft IRQ).
338	*/
339	get_online_cpus();
340	atomic_set(&kernel_threads_to_run, num_online_cpus());
341	for_each_online_cpu(cpu) {
342	INIT_DELAYED_WORK(&cpu_work[cpu], lttng_statedump_work_func);
343	schedule_delayed_work_on(cpu, &cpu_work[cpu], 0);
344	}
345	/* Wait for all threads to run */
346	__wait_event(statedump_wq, (atomic_read(&kernel_threads_to_run) != 0));
347	put_online_cpus();
348	/* Our work is done */
349	printk(KERN_DEBUG "LTT state dump end\n");
350	trace_lttng_statedump_end(session);
351	return 0;
352	}
353
354	/*
355	* Called with session mutex held.
356	*/
357	int lttng_statedump_start(struct lttng_session *session)
358	{
359	printk(KERN_DEBUG "LTTng: state dump begin\n");
360	return do_lttng_statedump(session);
361	}
362	EXPORT_SYMBOL_GPL(lttng_statedump_start);
363
364	MODULE_LICENSE("GPL and additional rights");
365	MODULE_AUTHOR("Jean-Hugues Deschenes");
366	MODULE_DESCRIPTION("Linux Trace Toolkit Next Generation Statedump");