diff options
Diffstat (limited to 'tools/perf/util/thread.c')
| -rw-r--r-- | tools/perf/util/thread.c | 478 |
1 files changed, 478 insertions, 0 deletions
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c new file mode 100644 index 000000000..665e5c061 --- /dev/null +++ b/tools/perf/util/thread.c @@ -0,0 +1,478 @@ +// 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); +} |