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perf record: Ensure space for lost samples

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Previous allocation didn't account for sample ID written after the
lost samples event. Switch from malloc/free to a stack allocation.

Reported-by: Milian Wolff <milian.wolff@kdab.com>
Closes: https://lore.kernel.org/linux-perf-users/23879991.0LEYPuXRzz@milian-workstation/
Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240611050626.1223155-1-irogers@google.com
This commit is contained in:
Ian Rogers 2024-06-10 22:06:26 -07:00 committed by Namhyung Kim
parent 6828d6929b
commit 6c1785cd75
2 changed files with 15 additions and 25 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

6
tools/lib/perf/include/perf/event.h
View file

@ -77,6 +77,12 @@ struct perf_record_lost_samples {
__u64 lost;
};
#define MAX_ID_HDR_ENTRIES 6
struct perf_record_lost_samples_and_ids {
struct perf_record_lost_samples lost;
__u64 sample_ids[MAX_ID_HDR_ENTRIES];
};
/*
* PERF_FORMAT_ENABLED | PERF_FORMAT_RUNNING | PERF_FORMAT_ID | PERF_FORMAT_LOST
*/

34
tools/perf/builtin-record.c
View file

@ -1926,7 +1926,7 @@ static void __record__save_lost_samples(struct record *rec, struct evsel *evsel,
static void record__read_lost_samples(struct record *rec)
{
struct perf_session *session = rec->session;
struct perf_record_lost_samples *lost = NULL;
struct perf_record_lost_samples_and_ids lost;
struct evsel *evsel;
/* there was an error during record__open */
@ -1951,20 +1951,13 @@ static void record__read_lost_samples(struct record *rec)
if (perf_evsel__read(&evsel->core, x, y, &count) < 0) {
pr_debug("read LOST count failed\n");
goto out;
return;
}
if (count.lost) {
if (!lost) {
lost = zalloc(sizeof(*lost) +
session->machines.host.id_hdr_size);
if (!lost) {
pr_debug("Memory allocation failed\n");
return;
}
lost->header.type = PERF_RECORD_LOST_SAMPLES;
}
__record__save_lost_samples(rec, evsel, lost,
memset(&lost.lost, 0, sizeof(lost));
lost.lost.header.type = PERF_RECORD_LOST_SAMPLES;
__record__save_lost_samples(rec, evsel, &lost.lost,
x, y, count.lost, 0);
}
}
@ -1972,21 +1965,12 @@ static void record__read_lost_samples(struct record *rec)
lost_count = perf_bpf_filter__lost_count(evsel);
if (lost_count) {
if (!lost) {
lost = zalloc(sizeof(*lost) +
session->machines.host.id_hdr_size);
if (!lost) {
pr_debug("Memory allocation failed\n");
return;
}
lost->header.type = PERF_RECORD_LOST_SAMPLES;
}
__record__save_lost_samples(rec, evsel, lost, 0, 0, lost_count,
memset(&lost.lost, 0, sizeof(lost));
lost.lost.header.type = PERF_RECORD_LOST_SAMPLES;
__record__save_lost_samples(rec, evsel, &lost.lost, 0, 0, lost_count,
PERF_RECORD_MISC_LOST_SAMPLES_BPF);
}
}
out:
free(lost);
}
static volatile sig_atomic_t workload_exec_errno;
@ -3198,7 +3182,7 @@ static int switch_output_setup(struct record *rec)
unsigned long val;
/*
* If we're using --switch-output-events, then we imply its
* If we're using --switch-output-events, then we imply its
* --switch-output=signal, as we'll send a SIGUSR2 from the side band
* thread to its parent.
*/