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perf inject: Fix build ID injection
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Build ID injection wasn't inserting a sample ID and aligning events to
64 bytes rather than 8. No sample ID means events are unordered and two
different build_id events for the same path, as happens when a file is
replaced, can't be differentiated.

Add in sample ID insertion for the build_id events alongside some
refactoring. The refactoring better aligns the function arguments for
different use cases, such as synthesizing build_id events without
needing to have a dso. The misc bits are explicitly passed as with
callchains the maps/dsos may span user and kernel land, so using
sample->cpumode isn't good enough.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Anne Macedo <retpolanne@posteo.net>
Cc: Casey Chen <cachen@purestorage.com>
Cc: Colin Ian King <colin.i.king@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sun Haiyong <sunhaiyong@loongson.cn>
Link: https://lore.kernel.org/r/20240909203740.143492-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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@captain5050 @acmel
captain5050 authored and acmel committed Sep 10, 2024
1 parent 0264878 commit ae39ba1
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Showing 4 changed files with 175 additions and 55 deletions.
170 changes: 131 additions & 39 deletions tools/perf/builtin-inject.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -130,6 +130,7 @@ struct perf_inject {
struct perf_file_section secs[HEADER_FEAT_BITS];
struct guest_session guest_session;
struct strlist *known_build_ids;
const struct evsel *mmap_evsel;
};

struct event_entry {
Expand All @@ -138,8 +139,13 @@ struct event_entry {
union perf_event event[];
};

static int dso__inject_build_id(struct dso *dso, const struct perf_tool *tool,
struct machine *machine, u8 cpumode, u32 flags);
static int tool__inject_build_id(const struct perf_tool *tool,
struct perf_sample *sample,
struct machine *machine,
const struct evsel *evsel,
__u16 misc,
const char *filename,
struct dso *dso, u32 flags);

static int output_bytes(struct perf_inject *inject, void *buf, size_t sz)
{
Expand Down Expand Up @@ -422,6 +428,28 @@ static struct dso *findnew_dso(int pid, int tid, const char *filename,
return dso;
}

/*
* The evsel used for the sample ID for mmap events. Typically stashed when
* processing mmap events. If not stashed, search the evlist for the first mmap
* gathering event.
*/
static const struct evsel *inject__mmap_evsel(struct perf_inject *inject)
{
struct evsel *pos;

if (inject->mmap_evsel)
return inject->mmap_evsel;

evlist__for_each_entry(inject->session->evlist, pos) {
if (pos->core.attr.mmap) {
inject->mmap_evsel = pos;
return pos;
}
}
pr_err("No mmap events found\n");
return NULL;
}

static int perf_event__repipe_common_mmap(const struct perf_tool *tool,
union perf_event *event,
struct perf_sample *sample,
Expand Down Expand Up @@ -469,12 +497,28 @@ static int perf_event__repipe_common_mmap(const struct perf_tool *tool,
}

if (dso && !dso__hit(dso)) {
dso__set_hit(dso);
dso__inject_build_id(dso, tool, machine, sample->cpumode, flags);
struct evsel *evsel = evlist__event2evsel(inject->session->evlist, event);

if (evsel) {
dso__set_hit(dso);
tool__inject_build_id(tool, sample, machine, evsel,
/*misc=*/sample->cpumode,
filename, dso, flags);
}
}
} else {
int err;

/*
* Remember the evsel for lazy build id generation. It is used
* for the sample id header type.
*/
if (inject->build_id_style == BID_RWS__INJECT_HEADER_LAZY &&
!inject->mmap_evsel)
inject->mmap_evsel = evlist__event2evsel(inject->session->evlist, event);

/* Create the thread, map, etc. Not done for the unordered inject all case. */
int err = perf_event_process(tool, event, sample, machine);
err = perf_event_process(tool, event, sample, machine);

if (err) {
dso__put(dso);
Expand Down Expand Up @@ -667,58 +711,95 @@ static bool perf_inject__lookup_known_build_id(struct perf_inject *inject,
return false;
}

static int dso__inject_build_id(struct dso *dso, const struct perf_tool *tool,
struct machine *machine, u8 cpumode, u32 flags)
static int tool__inject_build_id(const struct perf_tool *tool,
struct perf_sample *sample,
struct machine *machine,
const struct evsel *evsel,
__u16 misc,
const char *filename,
struct dso *dso, u32 flags)
{
struct perf_inject *inject = container_of(tool, struct perf_inject,
tool);
struct perf_inject *inject = container_of(tool, struct perf_inject, tool);
int err;

if (is_anon_memory(dso__long_name(dso)) || flags & MAP_HUGETLB)
if (is_anon_memory(filename) || flags & MAP_HUGETLB)
return 0;
if (is_no_dso_memory(dso__long_name(dso)))
if (is_no_dso_memory(filename))
return 0;

if (inject->known_build_ids != NULL &&
perf_inject__lookup_known_build_id(inject, dso))
return 1;

if (dso__read_build_id(dso) < 0) {
pr_debug("no build_id found for %s\n", dso__long_name(dso));
pr_debug("no build_id found for %s\n", filename);
return -1;
}

err = perf_event__synthesize_build_id(tool, dso, cpumode,
perf_event__repipe, machine);
err = perf_event__synthesize_build_id(tool, sample, machine,
perf_event__repipe,
evsel, misc, dso__bid(dso),
filename);
if (err) {
pr_err("Can't synthesize build_id event for %s\n", dso__long_name(dso));
pr_err("Can't synthesize build_id event for %s\n", filename);
return -1;
}

return 0;
}

static int mark_dso_hit(const struct perf_tool *tool,
struct perf_sample *sample,
struct machine *machine,
const struct evsel *mmap_evsel,
struct map *map, bool sample_in_dso)
{
struct dso *dso;
u16 misc = sample->cpumode;

if (!map)
return 0;

if (!sample_in_dso) {
u16 guest_mask = PERF_RECORD_MISC_GUEST_KERNEL |
PERF_RECORD_MISC_GUEST_USER;

if ((misc & guest_mask) != 0) {
misc &= PERF_RECORD_MISC_HYPERVISOR;
misc |= __map__is_kernel(map)
? PERF_RECORD_MISC_GUEST_KERNEL
: PERF_RECORD_MISC_GUEST_USER;
} else {
misc &= PERF_RECORD_MISC_HYPERVISOR;
misc |= __map__is_kernel(map)
? PERF_RECORD_MISC_KERNEL
: PERF_RECORD_MISC_USER;
}
}
dso = map__dso(map);
if (dso && !dso__hit(dso)) {
dso__set_hit(dso);
tool__inject_build_id(tool, sample, machine,
mmap_evsel, misc, dso__long_name(dso), dso,
map__flags(map));
}
return 0;
}

struct mark_dso_hit_args {
const struct perf_tool *tool;
struct perf_sample *sample;
struct machine *machine;
u8 cpumode;
const struct evsel *mmap_evsel;
};

static int mark_dso_hit_callback(struct callchain_cursor_node *node, void *data)
{
struct mark_dso_hit_args *args = data;
struct map *map = node->ms.map;

if (map) {
struct dso *dso = map__dso(map);

if (dso && !dso__hit(dso)) {
dso__set_hit(dso);
dso__inject_build_id(dso, args->tool, args->machine,
args->cpumode, map__flags(map));
}
}
return 0;
return mark_dso_hit(args->tool, args->sample, args->machine,
args->mmap_evsel, map, /*sample_in_dso=*/false);
}

int perf_event__inject_buildid(const struct perf_tool *tool, union perf_event *event,
Expand All @@ -728,10 +809,16 @@ int perf_event__inject_buildid(const struct perf_tool *tool, union perf_event *e
{
struct addr_location al;
struct thread *thread;
struct perf_inject *inject = container_of(tool, struct perf_inject, tool);
struct mark_dso_hit_args args = {
.tool = tool,
/*
* Use the parsed sample data of the sample event, which will
* have a later timestamp than the mmap event.
*/
.sample = sample,
.machine = machine,
.cpumode = sample->cpumode,
.mmap_evsel = inject__mmap_evsel(inject),
};

addr_location__init(&al);
Expand All @@ -743,13 +830,8 @@ int perf_event__inject_buildid(const struct perf_tool *tool, union perf_event *e
}

if (thread__find_map(thread, sample->cpumode, sample->ip, &al)) {
struct dso *dso = map__dso(al.map);

if (!dso__hit(dso)) {
dso__set_hit(dso);
dso__inject_build_id(dso, tool, machine,
sample->cpumode, map__flags(al.map));
}
mark_dso_hit(tool, sample, machine, args.mmap_evsel, al.map,
/*sample_in_dso=*/true);
}

sample__for_each_callchain_node(thread, evsel, sample, PERF_MAX_STACK_DEPTH,
Expand Down Expand Up @@ -1159,17 +1241,27 @@ static int process_build_id(const struct perf_tool *tool,
static int synthesize_build_id(struct perf_inject *inject, struct dso *dso, pid_t machine_pid)
{
struct machine *machine = perf_session__findnew_machine(inject->session, machine_pid);
u8 cpumode = dso__is_in_kernel_space(dso) ?
PERF_RECORD_MISC_GUEST_KERNEL :
PERF_RECORD_MISC_GUEST_USER;
struct perf_sample synth_sample = {
.pid = -1,
.tid = -1,
.time = -1,
.stream_id = -1,
.cpu = -1,
.period = 1,
.cpumode = dso__is_in_kernel_space(dso)
? PERF_RECORD_MISC_GUEST_KERNEL
: PERF_RECORD_MISC_GUEST_USER,
};

if (!machine)
return -ENOMEM;

dso__set_hit(dso);

return perf_event__synthesize_build_id(&inject->tool, dso, cpumode,
process_build_id, machine);
return perf_event__synthesize_build_id(&inject->tool, &synth_sample, machine,
process_build_id, inject__mmap_evsel(inject),
/*misc=*/synth_sample.cpumode,
dso__bid(dso), dso__long_name(dso));
}

static int guest_session__add_build_ids_cb(struct dso *dso, void *data)
Expand Down
6 changes: 3 additions & 3 deletions tools/perf/util/build-id.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -277,16 +277,16 @@ static int write_buildid(const char *name, size_t name_len, struct build_id *bid
struct perf_record_header_build_id b;
size_t len;

len = name_len + 1;
len = PERF_ALIGN(len, NAME_ALIGN);
len = sizeof(b) + name_len + 1;
len = PERF_ALIGN(len, sizeof(u64));

memset(&b, 0, sizeof(b));
memcpy(&b.data, bid->data, bid->size);
b.size = (u8) bid->size;
misc |= PERF_RECORD_MISC_BUILD_ID_SIZE;
b.pid = pid;
b.header.misc = misc;
b.header.size = sizeof(b) + len;
b.header.size = len;

err = do_write(fd, &b, sizeof(b));
if (err < 0)
Expand Down
44 changes: 32 additions & 12 deletions tools/perf/util/synthetic-events.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2225,28 +2225,48 @@ int perf_event__synthesize_tracing_data(const struct perf_tool *tool, int fd, st
}
#endif

int perf_event__synthesize_build_id(const struct perf_tool *tool, struct dso *pos, u16 misc,
perf_event__handler_t process, struct machine *machine)
int perf_event__synthesize_build_id(const struct perf_tool *tool,
struct perf_sample *sample,
struct machine *machine,
perf_event__handler_t process,
const struct evsel *evsel,
__u16 misc,
const struct build_id *bid,
const char *filename)
{
union perf_event ev;
size_t len;

if (!dso__hit(pos))
return 0;
len = sizeof(ev.build_id) + strlen(filename) + 1;
len = PERF_ALIGN(len, sizeof(u64));

memset(&ev, 0, sizeof(ev));
memset(&ev, 0, len);

len = dso__long_name_len(pos) + 1;
len = PERF_ALIGN(len, NAME_ALIGN);
ev.build_id.size = min(dso__bid(pos)->size, sizeof(dso__bid(pos)->data));
memcpy(&ev.build_id.build_id, dso__bid(pos)->data, ev.build_id.size);
ev.build_id.size = min(bid->size, sizeof(ev.build_id.build_id));
memcpy(ev.build_id.build_id, bid->data, ev.build_id.size);
ev.build_id.header.type = PERF_RECORD_HEADER_BUILD_ID;
ev.build_id.header.misc = misc | PERF_RECORD_MISC_BUILD_ID_SIZE;
ev.build_id.pid = machine->pid;
ev.build_id.header.size = sizeof(ev.build_id) + len;
memcpy(&ev.build_id.filename, dso__long_name(pos), dso__long_name_len(pos));
ev.build_id.header.size = len;
strcpy(ev.build_id.filename, filename);

if (evsel) {
void *array = &ev;
int ret;

return process(tool, &ev, NULL, machine);
array += ev.header.size;
ret = perf_event__synthesize_id_sample(array, evsel->core.attr.sample_type, sample);
if (ret < 0)
return ret;

if (ret & 7) {
pr_err("Bad id sample size %d\n", ret);
return -EINVAL;
}

ev.header.size += ret;
}
return process(tool, &ev, sample, machine);
}

int perf_event__synthesize_stat_events(struct perf_stat_config *config, const struct perf_tool *tool,
Expand Down
10 changes: 9 additions & 1 deletion tools/perf/util/synthetic-events.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@
#include <perf/cpumap.h>

struct auxtrace_record;
struct build_id;
struct dso;
struct evlist;
struct evsel;
Expand Down Expand Up @@ -45,7 +46,14 @@ typedef int (*perf_event__handler_t)(const struct perf_tool *tool, union perf_ev

int perf_event__synthesize_attrs(const struct perf_tool *tool, struct evlist *evlist, perf_event__handler_t process);
int perf_event__synthesize_attr(const struct perf_tool *tool, struct perf_event_attr *attr, u32 ids, u64 *id, perf_event__handler_t process);
int perf_event__synthesize_build_id(const struct perf_tool *tool, struct dso *pos, u16 misc, perf_event__handler_t process, struct machine *machine);
int perf_event__synthesize_build_id(const struct perf_tool *tool,
struct perf_sample *sample,
struct machine *machine,
perf_event__handler_t process,
const struct evsel *evsel,
__u16 misc,
const struct build_id *bid,
const char *filename);
int perf_event__synthesize_cpu_map(const struct perf_tool *tool, const struct perf_cpu_map *cpus, perf_event__handler_t process, struct machine *machine);
int perf_event__synthesize_event_update_cpus(const struct perf_tool *tool, struct evsel *evsel, perf_event__handler_t process);
int perf_event__synthesize_event_update_name(const struct perf_tool *tool, struct evsel *evsel, perf_event__handler_t process);
Expand Down

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