perf tools: Switch printf("...%s", strerror(errno)) to printf("...%m")

strerror() has thread safety issues, strerror_r() requires stack
allocated buffers.

Code in perf has already been using the "%m" formatting flag that is a
widely support glibc extension to print the current errno's description.

Expand the usage of this formatting flag and remove usage of
strerror()/strerror_r().

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: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Blake Jones <blakejones@google.com>
Cc: Chun-Tse Shao <ctshao@google.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Dr. David Alan Gilbert <linux@treblig.org>
Cc: Haibo Xu <haibo1.xu@intel.com>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Thomas Falcon <thomas.falcon@intel.com>
Cc: Yunseong Kim <ysk@kzalloc.com>
Cc: Zhongqiu Han <quic_zhonhan@quicinc.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

12 files changed, 60 insertions, 74 deletions

diff --git a/tools/perf/util/bpf-event.c b/tools/perf/util/bpf-event.c
index 2298cd396c42..2e6da3ad0a4f 100644
--- a/tools/perf/util/bpf-event.c
+++ b/tools/perf/util/bpf-event.c
@@ -787,11 +787,10 @@ int perf_event__synthesize_bpf_events(struct perf_session *session,
 				err = 0;
 				break;
 			}
-			pr_debug("%s: can't get next program: %s%s\n",
-				 __func__, strerror(errno),
-				 errno == EINVAL ? " -- kernel too old?" : "");
 			/* don't report error on old kernel or EPERM  */
 			err = (errno == EINVAL || errno == EPERM) ? 0 : -1;
+			pr_debug("%s: can\'t get next program: %m%s\n",
+				__func__, errno == EINVAL ? " -- kernel too old?" : "");
 			break;
 		}
 		fd = bpf_prog_get_fd_by_id(id);
@@ -824,10 +823,8 @@ int perf_event__synthesize_bpf_events(struct perf_session *session,
 		.tool    = session->tool,
 	};
 
-	if (kallsyms__parse(kallsyms_filename, &arg, kallsyms_process_symbol)) {
-		pr_err("%s: failed to synthesize bpf images: %s\n",
-		       __func__, strerror(errno));
-	}
+	if (kallsyms__parse(kallsyms_filename, &arg, kallsyms_process_symbol))
+		pr_err("%s: failed to synthesize bpf images: %m\n", __func__);
 
 	free(event);
 	return err;
diff --git a/tools/perf/util/bpf-utils.c b/tools/perf/util/bpf-utils.c
index 5a66dc8594aa..d6d2c9c190f7 100644
--- a/tools/perf/util/bpf-utils.c
+++ b/tools/perf/util/bpf-utils.c
@@ -123,7 +123,7 @@ get_bpf_prog_info_linear(int fd, __u64 arrays)
 	/* step 1: get array dimensions */
 	err = bpf_obj_get_info_by_fd(fd, &info, &info_len);
 	if (err) {
-		pr_debug("can't get prog info: %s", strerror(errno));
+		pr_debug("can't get prog info: %m\n");
 		return ERR_PTR(-EFAULT);
 	}
 	if (info.type >= __MAX_BPF_PROG_TYPE)
@@ -186,7 +186,7 @@ get_bpf_prog_info_linear(int fd, __u64 arrays)
 	/* step 5: call syscall again to get required arrays */
 	err = bpf_obj_get_info_by_fd(fd, &info_linear->info, &info_len);
 	if (err) {
-		pr_debug("can't get prog info: %s", strerror(errno));
+		pr_debug("can't get prog info: %m\n");
 		free(info_linear);
 		return ERR_PTR(-EFAULT);
 	}
diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c
index 7b5671f13c53..788d30be2058 100644
--- a/tools/perf/util/bpf_lock_contention.c
+++ b/tools/perf/util/bpf_lock_contention.c
@@ -42,7 +42,7 @@ static void check_slab_cache_iter(struct lock_contention *con)
 
 	con->btf = btf__load_vmlinux_btf();
 	if (con->btf == NULL) {
-		pr_debug("BTF loading failed: %s\n", strerror(errno));
+		pr_debug("BTF loading failed: %m\n");
 		return;
 	}
 
diff --git a/tools/perf/util/cap.c b/tools/perf/util/cap.c
index 24a0ea7e6d97..ac6d1d9a523d 100644
--- a/tools/perf/util/cap.c
+++ b/tools/perf/util/cap.c
@@ -28,8 +28,7 @@ bool perf_cap__capable(int cap, bool *used_root)
 		    header.version == _LINUX_CAPABILITY_VERSION_1)
 			continue;
 
-		pr_debug2("capget syscall failed (%s - %d) fall back on root check\n",
-			  strerror(errno), errno);
+		pr_debug2("capget syscall failed (%m) fall back on root check\n");
 		*used_root = true;
 		return geteuid() == 0;
 	}
diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
index 164eb45a0b36..90df41da1a32 100644
--- a/tools/perf/util/data.c
+++ b/tools/perf/util/data.c
@@ -213,17 +213,15 @@ static int check_backup(struct perf_data *data)
 
 		ret = rm_rf_perf_data(oldname);
 		if (ret) {
-			pr_err("Can't remove old data: %s (%s)\n",
-			       ret == -2 ?
-			       "Unknown file found" : strerror(errno),
-			       oldname);
+			if (ret == -2)
+				pr_err("Can't remove old data: Unknown file found (%s)\n", oldname);
+			else
+				pr_err("Can't remove old data: %m (%s)\n", oldname);
 			return -1;
 		}
 
 		if (rename(data->path, oldname)) {
-			pr_err("Can't move data: %s (%s to %s)\n",
-			       strerror(errno),
-			       data->path, oldname);
+			pr_err("Can't move data: %m (%s to %s)\n", data->path, oldname);
 			return -1;
 		}
 	}
@@ -246,14 +244,12 @@ static int open_file_read(struct perf_data *data)
 	int flags = data->in_place_update ? O_RDWR : O_RDONLY;
 	struct stat st;
 	int fd;
-	char sbuf[STRERR_BUFSIZE];
 
 	fd = open(data->file.path, flags);
 	if (fd < 0) {
 		int err = errno;
 
-		pr_err("failed to open %s: %s", data->file.path,
-			str_error_r(err, sbuf, sizeof(sbuf)));
+		pr_err("failed to open %s: %m", data->file.path);
 		if (err == ENOENT && !strcmp(data->file.path, "perf.data"))
 			pr_err("  (try 'perf record' first)");
 		pr_err("\n");
@@ -285,15 +281,10 @@ static int open_file_read(struct perf_data *data)
 
 static int open_file_write(struct perf_data *data)
 {
-	int fd;
-	char sbuf[STRERR_BUFSIZE];
-
-	fd = open(data->file.path, O_CREAT|O_RDWR|O_TRUNC|O_CLOEXEC,
-		  S_IRUSR|S_IWUSR);
+	int fd = open(data->file.path, O_CREAT|O_RDWR|O_TRUNC|O_CLOEXEC, S_IRUSR|S_IWUSR);
 
 	if (fd < 0)
-		pr_err("failed to open %s : %s\n", data->file.path,
-			str_error_r(errno, sbuf, sizeof(sbuf)));
+		pr_err("failed to open %s : %m\n", data->file.path);
 
 	return fd;
 }
@@ -436,8 +427,8 @@ int perf_data__switch(struct perf_data *data,
 
 		if (lseek(data->file.fd, pos, SEEK_SET) == (off_t)-1) {
 			ret = -errno;
-			pr_debug("Failed to lseek to %zu: %s",
-				 pos, strerror(errno));
+			pr_debug("Failed to lseek to %zu: %m\n",
+				 pos);
 			goto out;
 		}
 	}
diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 06980844c014..18e656712f5a 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -540,16 +540,13 @@ static void close_first_dso(void);
 
 static int do_open(char *name) EXCLUSIVE_LOCKS_REQUIRED(_dso__data_open_lock)
 {
-	int fd;
-	char sbuf[STRERR_BUFSIZE];
-
 	do {
-		fd = open(name, O_RDONLY|O_CLOEXEC);
+		int fd = open(name, O_RDONLY|O_CLOEXEC);
+
 		if (fd >= 0)
 			return fd;
 
-		pr_debug("dso open failed: %s\n",
-			 str_error_r(errno, sbuf, sizeof(sbuf)));
+		pr_debug("dso open failed: %m\n");
 		if (!dso__data_open_cnt || errno != EMFILE)
 			break;
 
@@ -1098,7 +1095,6 @@ static int file_size(struct dso *dso, struct machine *machine)
 {
 	int ret = 0;
 	struct stat st;
-	char sbuf[STRERR_BUFSIZE];
 
 	mutex_lock(dso__data_open_lock());
 
@@ -1116,8 +1112,7 @@ static int file_size(struct dso *dso, struct machine *machine)
 
 	if (fstat(dso__data(dso)->fd, &st) < 0) {
 		ret = -errno;
-		pr_err("dso cache fstat failed: %s\n",
-		       str_error_r(errno, sbuf, sizeof(sbuf)));
+		pr_err("dso cache fstat failed: %m\n");
 		dso__data(dso)->status = DSO_DATA_STATUS_ERROR;
 		goto out;
 	}
@@ -1773,10 +1768,8 @@ int dso__strerror_load(struct dso *dso, char *buf, size_t buflen)
 	BUG_ON(buflen == 0);
 
 	if (errnum >= 0) {
-		const char *err = str_error_r(errnum, buf, buflen);
-
-		if (err != buf)
-			scnprintf(buf, buflen, "%s", err);
+		errno = errnum;
+		scnprintf(buf, buflen, "%m");
 
 		return 0;
 	}
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 649519628541..3b0d837e3046 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1614,14 +1614,14 @@ int evlist__parse_sample_timestamp(struct evlist *evlist, union perf_event *even
 int evlist__strerror_open(struct evlist *evlist, int err, char *buf, size_t size)
 {
 	int printed, value;
-	char sbuf[STRERR_BUFSIZE], *emsg = str_error_r(err, sbuf, sizeof(sbuf));
 
 	switch (err) {
 	case EACCES:
 	case EPERM:
+		errno = err;
 		printed = scnprintf(buf, size,
-				    "Error:\t%s.\n"
-				    "Hint:\tCheck /proc/sys/kernel/perf_event_paranoid setting.", emsg);
+				    "Error:\t%m.\n"
+				    "Hint:\tCheck /proc/sys/kernel/perf_event_paranoid setting.");
 
 		value = perf_event_paranoid();
 
@@ -1648,16 +1648,18 @@ int evlist__strerror_open(struct evlist *evlist, int err, char *buf, size_t size
 		if (first->core.attr.sample_freq < (u64)max_freq)
 			goto out_default;
 
+		errno = err;
 		printed = scnprintf(buf, size,
-				    "Error:\t%s.\n"
+				    "Error:\t%m.\n"
 				    "Hint:\tCheck /proc/sys/kernel/perf_event_max_sample_rate.\n"
 				    "Hint:\tThe current value is %d and %" PRIu64 " is being requested.",
-				    emsg, max_freq, first->core.attr.sample_freq);
+				    max_freq, first->core.attr.sample_freq);
 		break;
 	}
 	default:
 out_default:
-		scnprintf(buf, size, "%s", emsg);
+		errno = err;
+		scnprintf(buf, size, "%m");
 		break;
 	}
 
@@ -1666,17 +1668,17 @@ out_default:
 
 int evlist__strerror_mmap(struct evlist *evlist, int err, char *buf, size_t size)
 {
-	char sbuf[STRERR_BUFSIZE], *emsg = str_error_r(err, sbuf, sizeof(sbuf));
 	int pages_attempted = evlist->core.mmap_len / 1024, pages_max_per_user, printed = 0;
 
 	switch (err) {
 	case EPERM:
 		sysctl__read_int("kernel/perf_event_mlock_kb", &pages_max_per_user);
+		errno = err;
 		printed += scnprintf(buf + printed, size - printed,
-				     "Error:\t%s.\n"
+				     "Error:\t%m.\n"
 				     "Hint:\tCheck /proc/sys/kernel/perf_event_mlock_kb (%d kB) setting.\n"
 				     "Hint:\tTried using %zd kB.\n",
-				     emsg, pages_max_per_user, pages_attempted);
+				     pages_max_per_user, pages_attempted);
 
 		if (pages_attempted >= pages_max_per_user) {
 			printed += scnprintf(buf + printed, size - printed,
@@ -1688,7 +1690,8 @@ int evlist__strerror_mmap(struct evlist *evlist, int err, char *buf, size_t size
 				     "Hint:\tTry using a smaller -m/--mmap-pages value.");
 		break;
 	default:
-		scnprintf(buf, size, "%s", emsg);
+		errno = err;
+		scnprintf(buf, size, "%m");
 		break;
 	}
 
@@ -1920,8 +1923,8 @@ static int evlist__parse_control_fifo(const char *str, int *ctl_fd, int *ctl_fd_
 	 */
 	fd = open(s, O_RDWR | O_NONBLOCK | O_CLOEXEC);
 	if (fd < 0) {
-		pr_err("Failed to open '%s'\n", s);
 		ret = -errno;
+		pr_err("Failed to open '%s': %m\n", s);
 		goto out_free;
 	}
 	*ctl_fd = fd;
@@ -1931,7 +1934,7 @@ static int evlist__parse_control_fifo(const char *str, int *ctl_fd, int *ctl_fd_
 		/* O_RDWR | O_NONBLOCK means the other end need not be open */
 		fd = open(p, O_RDWR | O_NONBLOCK | O_CLOEXEC);
 		if (fd < 0) {
-			pr_err("Failed to open '%s'\n", p);
+			pr_err("Failed to open '%s': %m\n", p);
 			ret = -errno;
 			goto out_free;
 		}
@@ -2364,7 +2367,7 @@ int evlist__parse_event_enable_time(struct evlist *evlist, struct record_opts *o
 	eet->timerfd = timerfd_create(CLOCK_MONOTONIC, TFD_CLOEXEC);
 	if (eet->timerfd == -1) {
 		err = -errno;
-		pr_err("timerfd_create failed: %s\n", strerror(errno));
+		pr_err("timerfd_create failed: %m\n");
 		goto free_eet_times;
 	}
 
@@ -2399,7 +2402,7 @@ static int event_enable_timer__set_timer(struct event_enable_timer *eet, int ms)
 
 	if (timerfd_settime(eet->timerfd, 0, &its, NULL) < 0) {
 		err = -errno;
-		pr_err("timerfd_settime failed: %s\n", strerror(errno));
+		pr_err("timerfd_settime failed: %m\n");
 	}
 	return err;
 }
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index ec6552a6f667..e2de642fbf53 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -648,8 +648,9 @@ struct tep_event *evsel__tp_format(struct evsel *evsel)
 	if (IS_ERR(tp_format)) {
 		int err = -PTR_ERR(evsel->tp_format);
 
-		pr_err("Error getting tracepoint format '%s' '%s'(%d)\n",
-			evsel__name(evsel), strerror(err), err);
+		errno = err;
+		pr_err("Error getting tracepoint format '%s': %m\n",
+			evsel__name(evsel));
 		return NULL;
 	}
 	evsel->tp_format = tp_format;
@@ -2772,8 +2773,8 @@ retry_open:
 					    PERF_EVENT_IOC_SET_BPF,
 					    bpf_fd);
 				if (err && errno != EEXIST) {
-					pr_err("failed to attach bpf fd %d: %s\n",
-					       bpf_fd, strerror(errno));
+					pr_err("failed to attach bpf fd %d: %m\n",
+					       bpf_fd);
 					err = -EINVAL;
 					goto out_close;
 				}
@@ -3864,7 +3865,6 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target,
 			 int err, char *msg, size_t size)
 {
 	struct perf_pmu *pmu;
-	char sbuf[STRERR_BUFSIZE];
 	int printed = 0, enforced = 0;
 	int ret;
 
@@ -3997,10 +3997,11 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target,
 	if (ret)
 		return ret;
 
+	errno = err;
 	return scnprintf(msg, size,
-	"The sys_perf_event_open() syscall returned with %d (%s) for event (%s).\n"
-	"\"dmesg | grep -i perf\" may provide additional information.\n",
-			 err, str_error_r(err, sbuf, sizeof(sbuf)), evsel__name(evsel));
+			 "The sys_perf_event_open() syscall failed for event (%s): %m\n"
+			 "\"dmesg | grep -i perf\" may provide additional information.\n",
+			 evsel__name(evsel));
 }
 
 struct perf_session *evsel__session(struct evsel *evsel)
diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c
index f00814e37de9..d4fe35f9d9a5 100644
--- a/tools/perf/util/jitdump.c
+++ b/tools/perf/util/jitdump.c
@@ -90,7 +90,8 @@ jit_emit_elf(struct jit_buf_desc *jd,
 	saved_errno = errno;
 	nsinfo__mountns_exit(&nsc);
 	if (fd == -1) {
-		pr_warning("cannot create jit ELF %s: %s\n", filename, strerror(saved_errno));
+		errno = saved_errno;
+		pr_warning("cannot create jit ELF %s: %m\n", filename);
 		return -1;
 	}
 
diff --git a/tools/perf/util/lzma.c b/tools/perf/util/lzma.c
index c355757ed391..91b9b5171d1f 100644
--- a/tools/perf/util/lzma.c
+++ b/tools/perf/util/lzma.c
@@ -59,7 +59,7 @@ int lzma_decompress_stream_to_file(FILE *infile, int output_fd)
 			strm.avail_in = fread(buf_in, 1, sizeof(buf_in), infile);
 
 			if (ferror(infile)) {
-				pr_debug("lzma: read error: %s\n", strerror(errno));
+				pr_debug("lzma: read error: %m\n");
 				goto err_lzma_end;
 			}
 
@@ -73,7 +73,7 @@ int lzma_decompress_stream_to_file(FILE *infile, int output_fd)
 			ssize_t write_size = sizeof(buf_out) - strm.avail_out;
 
 			if (writen(output_fd, buf_out, write_size) != write_size) {
-				pr_debug("lzma: write error: %s\n", strerror(errno));
+				pr_debug("lzma: write error: %m\n");
 				goto err_lzma_end;
 			}
 
@@ -103,7 +103,7 @@ int lzma_decompress_to_file(const char *input, int output_fd)
 
 	infile = fopen(input, "rb");
 	if (!infile) {
-		pr_debug("lzma: fopen failed on %s: '%s'\n", input, strerror(errno));
+		pr_debug("lzma: fopen failed on %s: '%m'\n", input);
 		return -1;
 	}
 
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 65fa9bdff1b8..922ef6577bbb 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -2349,9 +2349,10 @@ reader__read_event(struct reader *rd, struct perf_session *session,
 
 	if (size < sizeof(struct perf_event_header) ||
 	    (skip = rd->process(session, event, rd->file_pos, rd->path)) < 0) {
-		pr_err("%#" PRIx64 " [%#x]: failed to process type: %d [%s]\n",
+		errno = -skip;
+		pr_err("%#" PRIx64 " [%#x]: failed to process type: %d [%m]\n",
 		       rd->file_offset + rd->head, event->header.size,
-		       event->header.type, strerror(-skip));
+		       event->header.type);
 		err = skip;
 		goto out;
 	}
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index d1dcafa4b3b8..b8fea12997a0 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -1105,14 +1105,14 @@ static Elf *read_gnu_debugdata(struct dso *dso, Elf *elf, const char *name, int
 
 	wrapped = fmemopen(scn_data->d_buf, scn_data->d_size, "r");
 	if (!wrapped) {
-		pr_debug("%s: fmemopen: %s\n", __func__, strerror(errno));
+		pr_debug("%s: fmemopen: %m\n", __func__);
 		*dso__load_errno(dso) = -errno;
 		return NULL;
 	}
 
 	temp_fd = mkstemp(temp_filename);
 	if (temp_fd < 0) {
-		pr_debug("%s: mkstemp: %s\n", __func__, strerror(errno));
+		pr_debug("%s: mkstemp: %m\n", __func__);
 		*dso__load_errno(dso) = -errno;
 		fclose(wrapped);
 		return NULL;