blob: 665e5c0618ed3d330ff1bc0238f9bc1a3d4cdee7 [file] [log] [blame]
// 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->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);
}