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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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![Arnaldo Carvalho de Melo](/assets/img/avatar_default.png)
To allow for destructors to check if they're operating on a object still in a list, and to avoid going from use after free list entries into still valid, or even also other already removed from list entries. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Link: https://lkml.kernel.org/n/tip-deh17ub44atyox3j90e6rksu@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
447 lines
10 KiB
C
447 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include "../perf.h"
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#include <errno.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <linux/kernel.h>
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#include <linux/zalloc.h>
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#include "session.h"
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#include "thread.h"
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#include "thread-stack.h"
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#include "debug.h"
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#include "namespaces.h"
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#include "comm.h"
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#include "map.h"
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#include "symbol.h"
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#include "unwind.h"
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#include "callchain.h"
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#include <api/fs/fs.h>
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int thread__init_map_groups(struct thread *thread, struct machine *machine)
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{
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pid_t pid = thread->pid_;
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if (pid == thread->tid || pid == -1) {
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thread->mg = map_groups__new(machine);
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} else {
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struct thread *leader = __machine__findnew_thread(machine, pid, pid);
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if (leader) {
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thread->mg = map_groups__get(leader->mg);
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thread__put(leader);
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}
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}
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return thread->mg ? 0 : -1;
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}
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struct thread *thread__new(pid_t pid, pid_t tid)
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{
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char *comm_str;
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struct comm *comm;
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struct thread *thread = zalloc(sizeof(*thread));
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if (thread != NULL) {
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thread->pid_ = pid;
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thread->tid = tid;
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thread->ppid = -1;
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thread->cpu = -1;
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INIT_LIST_HEAD(&thread->namespaces_list);
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INIT_LIST_HEAD(&thread->comm_list);
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init_rwsem(&thread->namespaces_lock);
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init_rwsem(&thread->comm_lock);
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comm_str = malloc(32);
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if (!comm_str)
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goto err_thread;
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snprintf(comm_str, 32, ":%d", tid);
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comm = comm__new(comm_str, 0, false);
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free(comm_str);
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if (!comm)
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goto err_thread;
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list_add(&comm->list, &thread->comm_list);
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refcount_set(&thread->refcnt, 1);
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RB_CLEAR_NODE(&thread->rb_node);
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/* Thread holds first ref to nsdata. */
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thread->nsinfo = nsinfo__new(pid);
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srccode_state_init(&thread->srccode_state);
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}
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return thread;
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err_thread:
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free(thread);
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return NULL;
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}
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void thread__delete(struct thread *thread)
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{
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struct namespaces *namespaces, *tmp_namespaces;
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struct comm *comm, *tmp_comm;
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BUG_ON(!RB_EMPTY_NODE(&thread->rb_node));
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thread_stack__free(thread);
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if (thread->mg) {
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map_groups__put(thread->mg);
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thread->mg = NULL;
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}
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down_write(&thread->namespaces_lock);
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list_for_each_entry_safe(namespaces, tmp_namespaces,
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&thread->namespaces_list, list) {
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list_del_init(&namespaces->list);
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namespaces__free(namespaces);
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}
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up_write(&thread->namespaces_lock);
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down_write(&thread->comm_lock);
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list_for_each_entry_safe(comm, tmp_comm, &thread->comm_list, list) {
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list_del_init(&comm->list);
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comm__free(comm);
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}
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up_write(&thread->comm_lock);
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unwind__finish_access(thread);
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nsinfo__zput(thread->nsinfo);
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srccode_state_free(&thread->srccode_state);
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exit_rwsem(&thread->namespaces_lock);
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exit_rwsem(&thread->comm_lock);
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free(thread);
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}
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struct thread *thread__get(struct thread *thread)
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{
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if (thread)
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refcount_inc(&thread->refcnt);
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return thread;
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}
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void thread__put(struct thread *thread)
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{
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if (thread && refcount_dec_and_test(&thread->refcnt)) {
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/*
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* Remove it from the dead threads list, as last reference is
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* gone, if it is in a dead threads list.
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*
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* We may not be there anymore if say, the machine where it was
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* stored was already deleted, so we already removed it from
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* the dead threads and some other piece of code still keeps a
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* reference.
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*
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* This is what 'perf sched' does and finally drops it in
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* perf_sched__lat(), where it calls perf_sched__read_events(),
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* that processes the events by creating a session and deleting
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* it, which ends up destroying the list heads for the dead
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* threads, but before it does that it removes all threads from
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* it using list_del_init().
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*
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* So we need to check here if it is in a dead threads list and
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* if so, remove it before finally deleting the thread, to avoid
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* an use after free situation.
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*/
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if (!list_empty(&thread->node))
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list_del_init(&thread->node);
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thread__delete(thread);
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}
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}
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static struct namespaces *__thread__namespaces(const struct thread *thread)
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{
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if (list_empty(&thread->namespaces_list))
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return NULL;
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return list_first_entry(&thread->namespaces_list, struct namespaces, list);
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}
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struct namespaces *thread__namespaces(struct thread *thread)
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{
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struct namespaces *ns;
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down_read(&thread->namespaces_lock);
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ns = __thread__namespaces(thread);
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up_read(&thread->namespaces_lock);
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return ns;
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}
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static int __thread__set_namespaces(struct thread *thread, u64 timestamp,
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struct namespaces_event *event)
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{
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struct namespaces *new, *curr = __thread__namespaces(thread);
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new = namespaces__new(event);
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if (!new)
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return -ENOMEM;
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list_add(&new->list, &thread->namespaces_list);
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if (timestamp && curr) {
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/*
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* setns syscall must have changed few or all the namespaces
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* of this thread. Update end time for the namespaces
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* previously used.
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*/
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curr = list_next_entry(new, list);
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curr->end_time = timestamp;
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}
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return 0;
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}
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int thread__set_namespaces(struct thread *thread, u64 timestamp,
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struct namespaces_event *event)
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{
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int ret;
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down_write(&thread->namespaces_lock);
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ret = __thread__set_namespaces(thread, timestamp, event);
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up_write(&thread->namespaces_lock);
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return ret;
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}
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struct comm *thread__comm(const struct thread *thread)
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{
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if (list_empty(&thread->comm_list))
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return NULL;
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return list_first_entry(&thread->comm_list, struct comm, list);
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}
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struct comm *thread__exec_comm(const struct thread *thread)
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{
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struct comm *comm, *last = NULL;
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list_for_each_entry(comm, &thread->comm_list, list) {
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if (comm->exec)
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return comm;
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last = comm;
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}
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return last;
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}
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static int ____thread__set_comm(struct thread *thread, const char *str,
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u64 timestamp, bool exec)
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{
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struct comm *new, *curr = thread__comm(thread);
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/* Override the default :tid entry */
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if (!thread->comm_set) {
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int err = comm__override(curr, str, timestamp, exec);
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if (err)
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return err;
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} else {
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new = comm__new(str, timestamp, exec);
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if (!new)
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return -ENOMEM;
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list_add(&new->list, &thread->comm_list);
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if (exec)
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unwind__flush_access(thread);
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}
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thread->comm_set = true;
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return 0;
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}
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int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp,
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bool exec)
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{
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int ret;
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down_write(&thread->comm_lock);
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ret = ____thread__set_comm(thread, str, timestamp, exec);
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up_write(&thread->comm_lock);
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return ret;
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}
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int thread__set_comm_from_proc(struct thread *thread)
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{
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char path[64];
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char *comm = NULL;
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size_t sz;
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int err = -1;
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if (!(snprintf(path, sizeof(path), "%d/task/%d/comm",
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thread->pid_, thread->tid) >= (int)sizeof(path)) &&
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procfs__read_str(path, &comm, &sz) == 0) {
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comm[sz - 1] = '\0';
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err = thread__set_comm(thread, comm, 0);
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}
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return err;
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}
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static const char *__thread__comm_str(const struct thread *thread)
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{
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const struct comm *comm = thread__comm(thread);
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if (!comm)
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return NULL;
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return comm__str(comm);
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}
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const char *thread__comm_str(struct thread *thread)
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{
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const char *str;
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down_read(&thread->comm_lock);
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str = __thread__comm_str(thread);
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up_read(&thread->comm_lock);
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return str;
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}
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/* CHECKME: it should probably better return the max comm len from its comm list */
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int thread__comm_len(struct thread *thread)
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{
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if (!thread->comm_len) {
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const char *comm = thread__comm_str(thread);
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if (!comm)
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return 0;
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thread->comm_len = strlen(comm);
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}
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return thread->comm_len;
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}
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size_t thread__fprintf(struct thread *thread, FILE *fp)
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{
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return fprintf(fp, "Thread %d %s\n", thread->tid, thread__comm_str(thread)) +
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map_groups__fprintf(thread->mg, fp);
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}
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int thread__insert_map(struct thread *thread, struct map *map)
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{
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int ret;
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ret = unwind__prepare_access(thread, map, NULL);
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if (ret)
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return ret;
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map_groups__fixup_overlappings(thread->mg, map, stderr);
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map_groups__insert(thread->mg, map);
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return 0;
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}
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static int __thread__prepare_access(struct thread *thread)
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{
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bool initialized = false;
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int err = 0;
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struct maps *maps = &thread->mg->maps;
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struct map *map;
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down_read(&maps->lock);
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for (map = maps__first(maps); map; map = map__next(map)) {
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err = unwind__prepare_access(thread, map, &initialized);
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if (err || initialized)
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break;
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}
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up_read(&maps->lock);
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return err;
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}
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static int thread__prepare_access(struct thread *thread)
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{
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int err = 0;
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if (dwarf_callchain_users)
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err = __thread__prepare_access(thread);
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return err;
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}
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static int thread__clone_map_groups(struct thread *thread,
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struct thread *parent,
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bool do_maps_clone)
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{
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/* This is new thread, we share map groups for process. */
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if (thread->pid_ == parent->pid_)
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return thread__prepare_access(thread);
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if (thread->mg == parent->mg) {
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pr_debug("broken map groups on thread %d/%d parent %d/%d\n",
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thread->pid_, thread->tid, parent->pid_, parent->tid);
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return 0;
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}
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/* But this one is new process, copy maps. */
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return do_maps_clone ? map_groups__clone(thread, parent->mg) : 0;
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}
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int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone)
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{
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if (parent->comm_set) {
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const char *comm = thread__comm_str(parent);
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int err;
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if (!comm)
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return -ENOMEM;
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err = thread__set_comm(thread, comm, timestamp);
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if (err)
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return err;
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}
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thread->ppid = parent->tid;
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return thread__clone_map_groups(thread, parent, do_maps_clone);
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}
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void thread__find_cpumode_addr_location(struct thread *thread, u64 addr,
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struct addr_location *al)
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{
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size_t i;
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const u8 cpumodes[] = {
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PERF_RECORD_MISC_USER,
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PERF_RECORD_MISC_KERNEL,
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PERF_RECORD_MISC_GUEST_USER,
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PERF_RECORD_MISC_GUEST_KERNEL
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};
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for (i = 0; i < ARRAY_SIZE(cpumodes); i++) {
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thread__find_symbol(thread, cpumodes[i], addr, al);
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if (al->map)
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break;
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}
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}
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struct thread *thread__main_thread(struct machine *machine, struct thread *thread)
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{
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if (thread->pid_ == thread->tid)
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return thread__get(thread);
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if (thread->pid_ == -1)
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return NULL;
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return machine__find_thread(machine, thread->pid_, thread->pid_);
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}
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int thread__memcpy(struct thread *thread, struct machine *machine,
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void *buf, u64 ip, int len, bool *is64bit)
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{
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u8 cpumode = PERF_RECORD_MISC_USER;
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struct addr_location al;
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long offset;
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if (machine__kernel_ip(machine, ip))
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cpumode = PERF_RECORD_MISC_KERNEL;
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if (!thread__find_map(thread, cpumode, ip, &al) || !al.map->dso ||
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al.map->dso->data.status == DSO_DATA_STATUS_ERROR ||
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map__load(al.map) < 0)
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return -1;
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offset = al.map->map_ip(al.map, ip);
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if (is64bit)
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*is64bit = al.map->dso->is_64_bit;
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return dso__data_read_offset(al.map->dso, machine, offset, buf, len);
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}
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