linux/tools/perf/util/event.c
Andrew Lutomirski 6c6804fb2c perf symbols: Fix vsyscall symbol lookup
Perf can't currently trace into the vsyscall page.  It looks like it was
meant to work.

Tested on 2.6.38 and today's -git.

The bug is easy to reproduce.  Compile this:

int main()
{
	int i;
	struct timespec t;
	for(i = 0; i < 10000000; i++)
		clock_gettime(CLOCK_MONOTONIC, &t);
	return 0;
}

and run it through perf record; perf report.  The top entry shows
"[unknown]" and you can't zoom in.

It looks like there are two issues.  The first is a that a test for user
mode executing in kernel space is backwards.  (That's the first hunk
below).  The second (I think) is that something's wrong with the code
that generates lots of little struct dso objects for different sections
-- when it runs on vmlinux it results in bogus long_name values which
cause objdump to fail.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LPU-Reference: <AANLkTikxSw5+wJZUWNz++nL7mgivCh_Zf=2Kq6=f9Ce_@mail.gmail.com>
Signed-off-by: Andy Lutomirski <luto@mit.edu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2011-03-28 14:44:15 -03:00

794 lines
21 KiB
C

#include <linux/types.h>
#include "event.h"
#include "debug.h"
#include "session.h"
#include "sort.h"
#include "string.h"
#include "strlist.h"
#include "thread.h"
#include "thread_map.h"
static const char *perf_event__names[] = {
[0] = "TOTAL",
[PERF_RECORD_MMAP] = "MMAP",
[PERF_RECORD_LOST] = "LOST",
[PERF_RECORD_COMM] = "COMM",
[PERF_RECORD_EXIT] = "EXIT",
[PERF_RECORD_THROTTLE] = "THROTTLE",
[PERF_RECORD_UNTHROTTLE] = "UNTHROTTLE",
[PERF_RECORD_FORK] = "FORK",
[PERF_RECORD_READ] = "READ",
[PERF_RECORD_SAMPLE] = "SAMPLE",
[PERF_RECORD_HEADER_ATTR] = "ATTR",
[PERF_RECORD_HEADER_EVENT_TYPE] = "EVENT_TYPE",
[PERF_RECORD_HEADER_TRACING_DATA] = "TRACING_DATA",
[PERF_RECORD_HEADER_BUILD_ID] = "BUILD_ID",
[PERF_RECORD_FINISHED_ROUND] = "FINISHED_ROUND",
};
const char *perf_event__name(unsigned int id)
{
if (id >= ARRAY_SIZE(perf_event__names))
return "INVALID";
if (!perf_event__names[id])
return "UNKNOWN";
return perf_event__names[id];
}
static struct perf_sample synth_sample = {
.pid = -1,
.tid = -1,
.time = -1,
.stream_id = -1,
.cpu = -1,
.period = 1,
};
static pid_t perf_event__synthesize_comm(union perf_event *event, pid_t pid,
int full, perf_event__handler_t process,
struct perf_session *session)
{
char filename[PATH_MAX];
char bf[BUFSIZ];
FILE *fp;
size_t size = 0;
DIR *tasks;
struct dirent dirent, *next;
pid_t tgid = 0;
snprintf(filename, sizeof(filename), "/proc/%d/status", pid);
fp = fopen(filename, "r");
if (fp == NULL) {
out_race:
/*
* We raced with a task exiting - just return:
*/
pr_debug("couldn't open %s\n", filename);
return 0;
}
memset(&event->comm, 0, sizeof(event->comm));
while (!event->comm.comm[0] || !event->comm.pid) {
if (fgets(bf, sizeof(bf), fp) == NULL) {
pr_warning("couldn't get COMM and pgid, malformed %s\n", filename);
goto out;
}
if (memcmp(bf, "Name:", 5) == 0) {
char *name = bf + 5;
while (*name && isspace(*name))
++name;
size = strlen(name) - 1;
memcpy(event->comm.comm, name, size++);
} else if (memcmp(bf, "Tgid:", 5) == 0) {
char *tgids = bf + 5;
while (*tgids && isspace(*tgids))
++tgids;
tgid = event->comm.pid = atoi(tgids);
}
}
event->comm.header.type = PERF_RECORD_COMM;
size = ALIGN(size, sizeof(u64));
memset(event->comm.comm + size, 0, session->id_hdr_size);
event->comm.header.size = (sizeof(event->comm) -
(sizeof(event->comm.comm) - size) +
session->id_hdr_size);
if (!full) {
event->comm.tid = pid;
process(event, &synth_sample, session);
goto out;
}
snprintf(filename, sizeof(filename), "/proc/%d/task", pid);
tasks = opendir(filename);
if (tasks == NULL)
goto out_race;
while (!readdir_r(tasks, &dirent, &next) && next) {
char *end;
pid = strtol(dirent.d_name, &end, 10);
if (*end)
continue;
event->comm.tid = pid;
process(event, &synth_sample, session);
}
closedir(tasks);
out:
fclose(fp);
return tgid;
}
static int perf_event__synthesize_mmap_events(union perf_event *event,
pid_t pid, pid_t tgid,
perf_event__handler_t process,
struct perf_session *session)
{
char filename[PATH_MAX];
FILE *fp;
snprintf(filename, sizeof(filename), "/proc/%d/maps", pid);
fp = fopen(filename, "r");
if (fp == NULL) {
/*
* We raced with a task exiting - just return:
*/
pr_debug("couldn't open %s\n", filename);
return -1;
}
event->header.type = PERF_RECORD_MMAP;
/*
* Just like the kernel, see __perf_event_mmap in kernel/perf_event.c
*/
event->header.misc = PERF_RECORD_MISC_USER;
while (1) {
char bf[BUFSIZ], *pbf = bf;
int n;
size_t size;
if (fgets(bf, sizeof(bf), fp) == NULL)
break;
/* 00400000-0040c000 r-xp 00000000 fd:01 41038 /bin/cat */
n = hex2u64(pbf, &event->mmap.start);
if (n < 0)
continue;
pbf += n + 1;
n = hex2u64(pbf, &event->mmap.len);
if (n < 0)
continue;
pbf += n + 3;
if (*pbf == 'x') { /* vm_exec */
char *execname = strchr(bf, '/');
/* Catch VDSO */
if (execname == NULL)
execname = strstr(bf, "[vdso]");
if (execname == NULL)
continue;
pbf += 3;
n = hex2u64(pbf, &event->mmap.pgoff);
size = strlen(execname);
execname[size - 1] = '\0'; /* Remove \n */
memcpy(event->mmap.filename, execname, size);
size = ALIGN(size, sizeof(u64));
event->mmap.len -= event->mmap.start;
event->mmap.header.size = (sizeof(event->mmap) -
(sizeof(event->mmap.filename) - size));
memset(event->mmap.filename + size, 0, session->id_hdr_size);
event->mmap.header.size += session->id_hdr_size;
event->mmap.pid = tgid;
event->mmap.tid = pid;
process(event, &synth_sample, session);
}
}
fclose(fp);
return 0;
}
int perf_event__synthesize_modules(perf_event__handler_t process,
struct perf_session *session,
struct machine *machine)
{
struct rb_node *nd;
struct map_groups *kmaps = &machine->kmaps;
union perf_event *event = zalloc((sizeof(event->mmap) +
session->id_hdr_size));
if (event == NULL) {
pr_debug("Not enough memory synthesizing mmap event "
"for kernel modules\n");
return -1;
}
event->header.type = PERF_RECORD_MMAP;
/*
* kernel uses 0 for user space maps, see kernel/perf_event.c
* __perf_event_mmap
*/
if (machine__is_host(machine))
event->header.misc = PERF_RECORD_MISC_KERNEL;
else
event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
for (nd = rb_first(&kmaps->maps[MAP__FUNCTION]);
nd; nd = rb_next(nd)) {
size_t size;
struct map *pos = rb_entry(nd, struct map, rb_node);
if (pos->dso->kernel)
continue;
size = ALIGN(pos->dso->long_name_len + 1, sizeof(u64));
event->mmap.header.type = PERF_RECORD_MMAP;
event->mmap.header.size = (sizeof(event->mmap) -
(sizeof(event->mmap.filename) - size));
memset(event->mmap.filename + size, 0, session->id_hdr_size);
event->mmap.header.size += session->id_hdr_size;
event->mmap.start = pos->start;
event->mmap.len = pos->end - pos->start;
event->mmap.pid = machine->pid;
memcpy(event->mmap.filename, pos->dso->long_name,
pos->dso->long_name_len + 1);
process(event, &synth_sample, session);
}
free(event);
return 0;
}
static int __event__synthesize_thread(union perf_event *comm_event,
union perf_event *mmap_event,
pid_t pid, perf_event__handler_t process,
struct perf_session *session)
{
pid_t tgid = perf_event__synthesize_comm(comm_event, pid, 1, process,
session);
if (tgid == -1)
return -1;
return perf_event__synthesize_mmap_events(mmap_event, pid, tgid,
process, session);
}
int perf_event__synthesize_thread_map(struct thread_map *threads,
perf_event__handler_t process,
struct perf_session *session)
{
union perf_event *comm_event, *mmap_event;
int err = -1, thread;
comm_event = malloc(sizeof(comm_event->comm) + session->id_hdr_size);
if (comm_event == NULL)
goto out;
mmap_event = malloc(sizeof(mmap_event->mmap) + session->id_hdr_size);
if (mmap_event == NULL)
goto out_free_comm;
err = 0;
for (thread = 0; thread < threads->nr; ++thread) {
if (__event__synthesize_thread(comm_event, mmap_event,
threads->map[thread],
process, session)) {
err = -1;
break;
}
}
free(mmap_event);
out_free_comm:
free(comm_event);
out:
return err;
}
int perf_event__synthesize_threads(perf_event__handler_t process,
struct perf_session *session)
{
DIR *proc;
struct dirent dirent, *next;
union perf_event *comm_event, *mmap_event;
int err = -1;
comm_event = malloc(sizeof(comm_event->comm) + session->id_hdr_size);
if (comm_event == NULL)
goto out;
mmap_event = malloc(sizeof(mmap_event->mmap) + session->id_hdr_size);
if (mmap_event == NULL)
goto out_free_comm;
proc = opendir("/proc");
if (proc == NULL)
goto out_free_mmap;
while (!readdir_r(proc, &dirent, &next) && next) {
char *end;
pid_t pid = strtol(dirent.d_name, &end, 10);
if (*end) /* only interested in proper numerical dirents */
continue;
__event__synthesize_thread(comm_event, mmap_event, pid,
process, session);
}
closedir(proc);
err = 0;
out_free_mmap:
free(mmap_event);
out_free_comm:
free(comm_event);
out:
return err;
}
struct process_symbol_args {
const char *name;
u64 start;
};
static int find_symbol_cb(void *arg, const char *name, char type,
u64 start, u64 end __used)
{
struct process_symbol_args *args = arg;
/*
* Must be a function or at least an alias, as in PARISC64, where "_text" is
* an 'A' to the same address as "_stext".
*/
if (!(symbol_type__is_a(type, MAP__FUNCTION) ||
type == 'A') || strcmp(name, args->name))
return 0;
args->start = start;
return 1;
}
int perf_event__synthesize_kernel_mmap(perf_event__handler_t process,
struct perf_session *session,
struct machine *machine,
const char *symbol_name)
{
size_t size;
const char *filename, *mmap_name;
char path[PATH_MAX];
char name_buff[PATH_MAX];
struct map *map;
int err;
/*
* We should get this from /sys/kernel/sections/.text, but till that is
* available use this, and after it is use this as a fallback for older
* kernels.
*/
struct process_symbol_args args = { .name = symbol_name, };
union perf_event *event = zalloc((sizeof(event->mmap) +
session->id_hdr_size));
if (event == NULL) {
pr_debug("Not enough memory synthesizing mmap event "
"for kernel modules\n");
return -1;
}
mmap_name = machine__mmap_name(machine, name_buff, sizeof(name_buff));
if (machine__is_host(machine)) {
/*
* kernel uses PERF_RECORD_MISC_USER for user space maps,
* see kernel/perf_event.c __perf_event_mmap
*/
event->header.misc = PERF_RECORD_MISC_KERNEL;
filename = "/proc/kallsyms";
} else {
event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
if (machine__is_default_guest(machine))
filename = (char *) symbol_conf.default_guest_kallsyms;
else {
sprintf(path, "%s/proc/kallsyms", machine->root_dir);
filename = path;
}
}
if (kallsyms__parse(filename, &args, find_symbol_cb) <= 0)
return -ENOENT;
map = machine->vmlinux_maps[MAP__FUNCTION];
size = snprintf(event->mmap.filename, sizeof(event->mmap.filename),
"%s%s", mmap_name, symbol_name) + 1;
size = ALIGN(size, sizeof(u64));
event->mmap.header.type = PERF_RECORD_MMAP;
event->mmap.header.size = (sizeof(event->mmap) -
(sizeof(event->mmap.filename) - size) + session->id_hdr_size);
event->mmap.pgoff = args.start;
event->mmap.start = map->start;
event->mmap.len = map->end - event->mmap.start;
event->mmap.pid = machine->pid;
err = process(event, &synth_sample, session);
free(event);
return err;
}
int perf_event__process_comm(union perf_event *event,
struct perf_sample *sample __used,
struct perf_session *session)
{
struct thread *thread = perf_session__findnew(session, event->comm.tid);
dump_printf(": %s:%d\n", event->comm.comm, event->comm.tid);
if (thread == NULL || thread__set_comm(thread, event->comm.comm)) {
dump_printf("problem processing PERF_RECORD_COMM, skipping event.\n");
return -1;
}
return 0;
}
int perf_event__process_lost(union perf_event *event,
struct perf_sample *sample __used,
struct perf_session *session)
{
dump_printf(": id:%" PRIu64 ": lost:%" PRIu64 "\n",
event->lost.id, event->lost.lost);
session->hists.stats.total_lost += event->lost.lost;
return 0;
}
static void perf_event__set_kernel_mmap_len(union perf_event *event,
struct map **maps)
{
maps[MAP__FUNCTION]->start = event->mmap.start;
maps[MAP__FUNCTION]->end = event->mmap.start + event->mmap.len;
/*
* Be a bit paranoid here, some perf.data file came with
* a zero sized synthesized MMAP event for the kernel.
*/
if (maps[MAP__FUNCTION]->end == 0)
maps[MAP__FUNCTION]->end = ~0ULL;
}
static int perf_event__process_kernel_mmap(union perf_event *event,
struct perf_session *session)
{
struct map *map;
char kmmap_prefix[PATH_MAX];
struct machine *machine;
enum dso_kernel_type kernel_type;
bool is_kernel_mmap;
machine = perf_session__findnew_machine(session, event->mmap.pid);
if (!machine) {
pr_err("Can't find id %d's machine\n", event->mmap.pid);
goto out_problem;
}
machine__mmap_name(machine, kmmap_prefix, sizeof(kmmap_prefix));
if (machine__is_host(machine))
kernel_type = DSO_TYPE_KERNEL;
else
kernel_type = DSO_TYPE_GUEST_KERNEL;
is_kernel_mmap = memcmp(event->mmap.filename,
kmmap_prefix,
strlen(kmmap_prefix)) == 0;
if (event->mmap.filename[0] == '/' ||
(!is_kernel_mmap && event->mmap.filename[0] == '[')) {
char short_module_name[1024];
char *name, *dot;
if (event->mmap.filename[0] == '/') {
name = strrchr(event->mmap.filename, '/');
if (name == NULL)
goto out_problem;
++name; /* skip / */
dot = strrchr(name, '.');
if (dot == NULL)
goto out_problem;
snprintf(short_module_name, sizeof(short_module_name),
"[%.*s]", (int)(dot - name), name);
strxfrchar(short_module_name, '-', '_');
} else
strcpy(short_module_name, event->mmap.filename);
map = machine__new_module(machine, event->mmap.start,
event->mmap.filename);
if (map == NULL)
goto out_problem;
name = strdup(short_module_name);
if (name == NULL)
goto out_problem;
map->dso->short_name = name;
map->dso->sname_alloc = 1;
map->end = map->start + event->mmap.len;
} else if (is_kernel_mmap) {
const char *symbol_name = (event->mmap.filename +
strlen(kmmap_prefix));
/*
* Should be there already, from the build-id table in
* the header.
*/
struct dso *kernel = __dsos__findnew(&machine->kernel_dsos,
kmmap_prefix);
if (kernel == NULL)
goto out_problem;
kernel->kernel = kernel_type;
if (__machine__create_kernel_maps(machine, kernel) < 0)
goto out_problem;
perf_event__set_kernel_mmap_len(event, machine->vmlinux_maps);
perf_session__set_kallsyms_ref_reloc_sym(machine->vmlinux_maps,
symbol_name,
event->mmap.pgoff);
if (machine__is_default_guest(machine)) {
/*
* preload dso of guest kernel and modules
*/
dso__load(kernel, machine->vmlinux_maps[MAP__FUNCTION],
NULL);
}
}
return 0;
out_problem:
return -1;
}
int perf_event__process_mmap(union perf_event *event,
struct perf_sample *sample __used,
struct perf_session *session)
{
struct machine *machine;
struct thread *thread;
struct map *map;
u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
int ret = 0;
dump_printf(" %d/%d: [%#" PRIx64 "(%#" PRIx64 ") @ %#" PRIx64 "]: %s\n",
event->mmap.pid, event->mmap.tid, event->mmap.start,
event->mmap.len, event->mmap.pgoff, event->mmap.filename);
if (cpumode == PERF_RECORD_MISC_GUEST_KERNEL ||
cpumode == PERF_RECORD_MISC_KERNEL) {
ret = perf_event__process_kernel_mmap(event, session);
if (ret < 0)
goto out_problem;
return 0;
}
machine = perf_session__find_host_machine(session);
if (machine == NULL)
goto out_problem;
thread = perf_session__findnew(session, event->mmap.pid);
if (thread == NULL)
goto out_problem;
map = map__new(&machine->user_dsos, event->mmap.start,
event->mmap.len, event->mmap.pgoff,
event->mmap.pid, event->mmap.filename,
MAP__FUNCTION);
if (map == NULL)
goto out_problem;
thread__insert_map(thread, map);
return 0;
out_problem:
dump_printf("problem processing PERF_RECORD_MMAP, skipping event.\n");
return 0;
}
int perf_event__process_task(union perf_event *event,
struct perf_sample *sample __used,
struct perf_session *session)
{
struct thread *thread = perf_session__findnew(session, event->fork.tid);
struct thread *parent = perf_session__findnew(session, event->fork.ptid);
dump_printf("(%d:%d):(%d:%d)\n", event->fork.pid, event->fork.tid,
event->fork.ppid, event->fork.ptid);
if (event->header.type == PERF_RECORD_EXIT) {
perf_session__remove_thread(session, thread);
return 0;
}
if (thread == NULL || parent == NULL ||
thread__fork(thread, parent) < 0) {
dump_printf("problem processing PERF_RECORD_FORK, skipping event.\n");
return -1;
}
return 0;
}
int perf_event__process(union perf_event *event, struct perf_sample *sample,
struct perf_session *session)
{
switch (event->header.type) {
case PERF_RECORD_COMM:
perf_event__process_comm(event, sample, session);
break;
case PERF_RECORD_MMAP:
perf_event__process_mmap(event, sample, session);
break;
case PERF_RECORD_FORK:
case PERF_RECORD_EXIT:
perf_event__process_task(event, sample, session);
break;
case PERF_RECORD_LOST:
perf_event__process_lost(event, sample, session);
default:
break;
}
return 0;
}
void thread__find_addr_map(struct thread *self,
struct perf_session *session, u8 cpumode,
enum map_type type, pid_t pid, u64 addr,
struct addr_location *al)
{
struct map_groups *mg = &self->mg;
struct machine *machine = NULL;
al->thread = self;
al->addr = addr;
al->cpumode = cpumode;
al->filtered = false;
if (cpumode == PERF_RECORD_MISC_KERNEL && perf_host) {
al->level = 'k';
machine = perf_session__find_host_machine(session);
if (machine == NULL) {
al->map = NULL;
return;
}
mg = &machine->kmaps;
} else if (cpumode == PERF_RECORD_MISC_USER && perf_host) {
al->level = '.';
machine = perf_session__find_host_machine(session);
} else if (cpumode == PERF_RECORD_MISC_GUEST_KERNEL && perf_guest) {
al->level = 'g';
machine = perf_session__find_machine(session, pid);
if (machine == NULL) {
al->map = NULL;
return;
}
mg = &machine->kmaps;
} else {
/*
* 'u' means guest os user space.
* TODO: We don't support guest user space. Might support late.
*/
if (cpumode == PERF_RECORD_MISC_GUEST_USER && perf_guest)
al->level = 'u';
else
al->level = 'H';
al->map = NULL;
if ((cpumode == PERF_RECORD_MISC_GUEST_USER ||
cpumode == PERF_RECORD_MISC_GUEST_KERNEL) &&
!perf_guest)
al->filtered = true;
if ((cpumode == PERF_RECORD_MISC_USER ||
cpumode == PERF_RECORD_MISC_KERNEL) &&
!perf_host)
al->filtered = true;
return;
}
try_again:
al->map = map_groups__find(mg, type, al->addr);
if (al->map == NULL) {
/*
* If this is outside of all known maps, and is a negative
* address, try to look it up in the kernel dso, as it might be
* a vsyscall or vdso (which executes in user-mode).
*
* XXX This is nasty, we should have a symbol list in the
* "[vdso]" dso, but for now lets use the old trick of looking
* in the whole kernel symbol list.
*/
if ((long long)al->addr < 0 &&
cpumode == PERF_RECORD_MISC_USER &&
machine && mg != &machine->kmaps) {
mg = &machine->kmaps;
goto try_again;
}
} else
al->addr = al->map->map_ip(al->map, al->addr);
}
void thread__find_addr_location(struct thread *self,
struct perf_session *session, u8 cpumode,
enum map_type type, pid_t pid, u64 addr,
struct addr_location *al,
symbol_filter_t filter)
{
thread__find_addr_map(self, session, cpumode, type, pid, addr, al);
if (al->map != NULL)
al->sym = map__find_symbol(al->map, al->addr, filter);
else
al->sym = NULL;
}
int perf_event__preprocess_sample(const union perf_event *event,
struct perf_session *session,
struct addr_location *al,
struct perf_sample *sample,
symbol_filter_t filter)
{
u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
struct thread *thread = perf_session__findnew(session, event->ip.pid);
if (thread == NULL)
return -1;
if (symbol_conf.comm_list &&
!strlist__has_entry(symbol_conf.comm_list, thread->comm))
goto out_filtered;
dump_printf(" ... thread: %s:%d\n", thread->comm, thread->pid);
/*
* Have we already created the kernel maps for the host machine?
*
* This should have happened earlier, when we processed the kernel MMAP
* events, but for older perf.data files there was no such thing, so do
* it now.
*/
if (cpumode == PERF_RECORD_MISC_KERNEL &&
session->host_machine.vmlinux_maps[MAP__FUNCTION] == NULL)
machine__create_kernel_maps(&session->host_machine);
thread__find_addr_map(thread, session, cpumode, MAP__FUNCTION,
event->ip.pid, event->ip.ip, al);
dump_printf(" ...... dso: %s\n",
al->map ? al->map->dso->long_name :
al->level == 'H' ? "[hypervisor]" : "<not found>");
al->sym = NULL;
al->cpu = sample->cpu;
if (al->map) {
if (symbol_conf.dso_list &&
(!al->map || !al->map->dso ||
!(strlist__has_entry(symbol_conf.dso_list,
al->map->dso->short_name) ||
(al->map->dso->short_name != al->map->dso->long_name &&
strlist__has_entry(symbol_conf.dso_list,
al->map->dso->long_name)))))
goto out_filtered;
al->sym = map__find_symbol(al->map, al->addr, filter);
}
if (symbol_conf.sym_list && al->sym &&
!strlist__has_entry(symbol_conf.sym_list, al->sym->name))
goto out_filtered;
return 0;
out_filtered:
al->filtered = true;
return 0;
}