summaryrefslogtreecommitdiff
path: root/tools/perf/util/thread.c
blob: e3e5427e1c3c8702d23854bd7643923a6752a372 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
// SPDX-License-Identifier: GPL-2.0
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <linux/kernel.h>
#include <linux/zalloc.h>
#include "dso.h"
#include "session.h"
#include "thread.h"
#include "thread-stack.h"
#include "debug.h"
#include "namespaces.h"
#include "comm.h"
#include "map.h"
#include "symbol.h"
#include "unwind.h"
#include "callchain.h"

#include <api/fs/fs.h>

int thread__init_maps(struct thread *thread, struct machine *machine)
{
	pid_t pid = thread->pid_;

	if (pid == thread->tid || pid == -1) {
		thread->maps = maps__new(machine);
	} else {
		struct thread *leader = __machine__findnew_thread(machine, pid, pid);
		if (leader) {
			thread->maps = maps__get(leader->maps);
			thread__put(leader);
		}
	}

	return thread->maps ? 0 : -1;
}

struct thread *thread__new(pid_t pid, pid_t tid)
{
	char *comm_str;
	struct comm *comm;
	struct thread *thread = zalloc(sizeof(*thread));

	if (thread != NULL) {
		thread->pid_ = pid;
		thread->tid = tid;
		thread->ppid = -1;
		thread->cpu = -1;
		thread->guest_cpu = -1;
		thread->lbr_stitch_enable = false;
		INIT_LIST_HEAD(&thread->namespaces_list);
		INIT_LIST_HEAD(&thread->comm_list);
		init_rwsem(&thread->namespaces_lock);
		init_rwsem(&thread->comm_lock);

		comm_str = malloc(32);
		if (!comm_str)
			goto err_thread;

		snprintf(comm_str, 32, ":%d", tid);
		comm = comm__new(comm_str, 0, false);
		free(comm_str);
		if (!comm)
			goto err_thread;

		list_add(&comm->list, &thread->comm_list);
		refcount_set(&thread->refcnt, 1);
		RB_CLEAR_NODE(&thread->rb_node);
		/* Thread holds first ref to nsdata. */
		thread->nsinfo = nsinfo__new(pid);
		srccode_state_init(&thread->srccode_state);
	}

	return thread;

err_thread:
	free(thread);
	return NULL;
}

void thread__delete(struct thread *thread)
{
	struct namespaces *namespaces, *tmp_namespaces;
	struct comm *comm, *tmp_comm;

	BUG_ON(!RB_EMPTY_NODE(&thread->rb_node));

	thread_stack__free(thread);

	if (thread->maps) {
		maps__put(thread->maps);
		thread->maps = NULL;
	}
	down_write(&thread->namespaces_lock);
	list_for_each_entry_safe(namespaces, tmp_namespaces,
				 &thread->namespaces_list, list) {
		list_del_init(&namespaces->list);
		namespaces__free(namespaces);
	}
	up_write(&thread->namespaces_lock);

	down_write(&thread->comm_lock);
	list_for_each_entry_safe(comm, tmp_comm, &thread->comm_list, list) {
		list_del_init(&comm->list);
		comm__free(comm);
	}
	up_write(&thread->comm_lock);

	nsinfo__zput(thread->nsinfo);
	srccode_state_free(&thread->srccode_state);

	exit_rwsem(&thread->namespaces_lock);
	exit_rwsem(&thread->comm_lock);
	thread__free_stitch_list(thread);
	free(thread);
}

struct thread *thread__get(struct thread *thread)
{
	if (thread)
		refcount_inc(&thread->refcnt);
	return thread;
}

void thread__put(struct thread *thread)
{
	if (thread && refcount_dec_and_test(&thread->refcnt)) {
		/*
		 * Remove it from the dead threads list, as last reference is
		 * gone, if it is in a dead threads list.
		 *
		 * We may not be there anymore if say, the machine where it was
		 * stored was already deleted, so we already removed it from
		 * the dead threads and some other piece of code still keeps a
		 * reference.
		 *
		 * This is what 'perf sched' does and finally drops it in
		 * perf_sched__lat(), where it calls perf_sched__read_events(),
		 * that processes the events by creating a session and deleting
		 * it, which ends up destroying the list heads for the dead
		 * threads, but before it does that it removes all threads from
		 * it using list_del_init().
		 *
		 * So we need to check here if it is in a dead threads list and
		 * if so, remove it before finally deleting the thread, to avoid
		 * an use after free situation.
		 */
		if (!list_empty(&thread->node))
			list_del_init(&thread->node);
		thread__delete(thread);
	}
}

static struct namespaces *__thread__namespaces(const struct thread *thread)
{
	if (list_empty(&thread->namespaces_list))
		return NULL;

	return list_first_entry(&thread->namespaces_list, struct namespaces, list);
}

struct namespaces *thread__namespaces(struct thread *thread)
{
	struct namespaces *ns;

	down_read(&thread->namespaces_lock);
	ns = __thread__namespaces(thread);
	up_read(&thread->namespaces_lock);

	return ns;
}

static int __thread__set_namespaces(struct thread *thread, u64 timestamp,
				    struct perf_record_namespaces *event)
{
	struct namespaces *new, *curr = __thread__namespaces(thread);

	new = namespaces__new(event);
	if (!new)
		return -ENOMEM;

	list_add(&new->list, &thread->namespaces_list);

	if (timestamp && curr) {
		/*
		 * setns syscall must have changed few or all the namespaces
		 * of this thread. Update end time for the namespaces
		 * previously used.
		 */
		curr = list_next_entry(new, list);
		curr->end_time = timestamp;
	}

	return 0;
}

int thread__set_namespaces(struct thread *thread, u64 timestamp,
			   struct perf_record_namespaces *event)
{
	int ret;

	down_write(&thread->namespaces_lock);
	ret = __thread__set_namespaces(thread, timestamp, event);
	up_write(&thread->namespaces_lock);
	return ret;
}

struct comm *thread__comm(const struct thread *thread)
{
	if (list_empty(&thread->comm_list))
		return NULL;

	return list_first_entry(&thread->comm_list, struct comm, list);
}

struct comm *thread__exec_comm(const struct thread *thread)
{
	struct comm *comm, *last = NULL, *second_last = NULL;

	list_for_each_entry(comm, &thread->comm_list, list) {
		if (comm->exec)
			return comm;
		second_last = last;
		last = comm;
	}

	/*
	 * 'last' with no start time might be the parent's comm of a synthesized
	 * thread (created by processing a synthesized fork event). For a main
	 * thread, that is very probably wrong. Prefer a later comm to avoid
	 * that case.
	 */
	if (second_last && !last->start && thread->pid_ == thread->tid)
		return second_last;

	return last;
}

static int ____thread__set_comm(struct thread *thread, const char *str,
				u64 timestamp, bool exec)
{
	struct comm *new, *curr = thread__comm(thread);

	/* Override the default :tid entry */
	if (!thread->comm_set) {
		int err = comm__override(curr, str, timestamp, exec);
		if (err)
			return err;
	} else {
		new = comm__new(str, timestamp, exec);
		if (!new)
			return -ENOMEM;
		list_add(&new->list, &thread->comm_list);

		if (exec)
			unwind__flush_access(thread->maps);
	}

	thread->comm_set = true;

	return 0;
}

int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
		       bool exec)
{
	int ret;

	down_write(&thread->comm_lock);
	ret = ____thread__set_comm(thread, str, timestamp, exec);
	up_write(&thread->comm_lock);
	return ret;
}

int thread__set_comm_from_proc(struct thread *thread)
{
	char path[64];
	char *comm = NULL;
	size_t sz;
	int err = -1;

	if (!(snprintf(path, sizeof(path), "%d/task/%d/comm",
		       thread->pid_, thread->tid) >= (int)sizeof(path)) &&
	    procfs__read_str(path, &comm, &sz) == 0) {
		comm[sz - 1] = '\0';
		err = thread__set_comm(thread, comm, 0);
	}

	return err;
}

static const char *__thread__comm_str(const struct thread *thread)
{
	const struct comm *comm = thread__comm(thread);

	if (!comm)
		return NULL;

	return comm__str(comm);
}

const char *thread__comm_str(struct thread *thread)
{
	const char *str;

	down_read(&thread->comm_lock);
	str = __thread__comm_str(thread);
	up_read(&thread->comm_lock);

	return str;
}

/* CHECKME: it should probably better return the max comm len from its comm list */
int thread__comm_len(struct thread *thread)
{
	if (!thread->comm_len) {
		const char *comm = thread__comm_str(thread);
		if (!comm)
			return 0;
		thread->comm_len = strlen(comm);
	}

	return thread->comm_len;
}

size_t thread__fprintf(struct thread *thread, FILE *fp)
{
	return fprintf(fp, "Thread %d %s\n", thread->tid, thread__comm_str(thread)) +
	       maps__fprintf(thread->maps, fp);
}

int thread__insert_map(struct thread *thread, struct map *map)
{
	int ret;

	ret = unwind__prepare_access(thread->maps, map, NULL);
	if (ret)
		return ret;

	maps__fixup_overlappings(thread->maps, map, stderr);
	maps__insert(thread->maps, map);

	return 0;
}

static int __thread__prepare_access(struct thread *thread)
{
	bool initialized = false;
	int err = 0;
	struct maps *maps = thread->maps;
	struct map *map;

	down_read(&maps->lock);

	maps__for_each_entry(maps, map) {
		err = unwind__prepare_access(thread->maps, map, &initialized);
		if (err || initialized)
			break;
	}

	up_read(&maps->lock);

	return err;
}

static int thread__prepare_access(struct thread *thread)
{
	int err = 0;

	if (dwarf_callchain_users)
		err = __thread__prepare_access(thread);

	return err;
}

static int thread__clone_maps(struct thread *thread, struct thread *parent, bool do_maps_clone)
{
	/* This is new thread, we share map groups for process. */
	if (thread->pid_ == parent->pid_)
		return thread__prepare_access(thread);

	if (thread->maps == parent->maps) {
		pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
			 thread->pid_, thread->tid, parent->pid_, parent->tid);
		return 0;
	}
	/* But this one is new process, copy maps. */
	return do_maps_clone ? maps__clone(thread, parent->maps) : 0;
}

int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone)
{
	if (parent->comm_set) {
		const char *comm = thread__comm_str(parent);
		int err;
		if (!comm)
			return -ENOMEM;
		err = thread__set_comm(thread, comm, timestamp);
		if (err)
			return err;
	}

	thread->ppid = parent->tid;
	return thread__clone_maps(thread, parent, do_maps_clone);
}

void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
					struct addr_location *al)
{
	size_t i;
	const u8 cpumodes[] = {
		PERF_RECORD_MISC_USER,
		PERF_RECORD_MISC_KERNEL,
		PERF_RECORD_MISC_GUEST_USER,
		PERF_RECORD_MISC_GUEST_KERNEL
	};

	for (i = 0; i < ARRAY_SIZE(cpumodes); i++) {
		thread__find_symbol(thread, cpumodes[i], addr, al);
		if (al->map)
			break;
	}
}

struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
{
	if (thread->pid_ == thread->tid)
		return thread__get(thread);

	if (thread->pid_ == -1)
		return NULL;

	return machine__find_thread(machine, thread->pid_, thread->pid_);
}

int thread__memcpy(struct thread *thread, struct machine *machine,
		   void *buf, u64 ip, int len, bool *is64bit)
{
       u8 cpumode = PERF_RECORD_MISC_USER;
       struct addr_location al;
       long offset;

       if (machine__kernel_ip(machine, ip))
               cpumode = PERF_RECORD_MISC_KERNEL;

       if (!thread__find_map(thread, cpumode, ip, &al) || !al.map->dso ||
	   al.map->dso->data.status == DSO_DATA_STATUS_ERROR ||
	   map__load(al.map) < 0)
               return -1;

       offset = al.map->map_ip(al.map, ip);
       if (is64bit)
               *is64bit = al.map->dso->is_64_bit;

       return dso__data_read_offset(al.map->dso, machine, offset, buf, len);
}

void thread__free_stitch_list(struct thread *thread)
{
	struct lbr_stitch *lbr_stitch = thread->lbr_stitch;
	struct stitch_list *pos, *tmp;

	if (!lbr_stitch)
		return;

	list_for_each_entry_safe(pos, tmp, &lbr_stitch->lists, node) {
		list_del_init(&pos->node);
		free(pos);
	}

	list_for_each_entry_safe(pos, tmp, &lbr_stitch->free_lists, node) {
		list_del_init(&pos->node);
		free(pos);
	}

	zfree(&lbr_stitch->prev_lbr_cursor);
	zfree(&thread->lbr_stitch);
}