perf session: Return error code for perf_session__new() function on failure

This patch is to return error code of perf_new_session function on
failure instead of NULL.

Test Results:

Before Fix:

  $ perf c2c report -input
  failed to open nput: No such file or directory

  $ echo $?
  0
  $

After Fix:

  $ perf c2c report -input
  failed to open nput: No such file or directory

  $ echo $?
  254
  $

Committer notes:

Fix 'perf tests topology' case, where we use that TEST_ASSERT_VAL(...,
session), i.e. we need to pass zero in case of failure, which was the
case before when NULL was returned by perf_session__new() for failure,
but now we need to negate the result of IS_ERR(session) to respect that
TEST_ASSERT_VAL) expectation of zero meaning failure.

Reported-by: Nageswara R Sastry <rnsastry@linux.vnet.ibm.com>
Signed-off-by: Mamatha Inamdar <mamatha4@linux.vnet.ibm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tested-by: Nageswara R Sastry <rnsastry@linux.vnet.ibm.com>
Acked-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jeremie Galarneau <jeremie.galarneau@efficios.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shawn Landden <shawn@git.icu>
Cc: Song Liu <songliubraving@fb.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tzvetomir Stoyanov <tstoyanov@vmware.com>
Link: http://lore.kernel.org/lkml/20190822071223.17892.45782.stgit@localhost.localdomain
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

22 files changed, 86 insertions, 57 deletions

diff --git a/tools/perf/builtin-annotate.c b/tools/perf/builtin-annotate.c
index 553c651fa0a2..8db8fc9bddef 100644
--- a/tools/perf/builtin-annotate.c
+++ b/tools/perf/builtin-annotate.c
@@ -40,6 +40,7 @@
 #include <dlfcn.h>
 #include <errno.h>
 #include <linux/bitmap.h>
+#include <linux/err.h>
 
 struct perf_annotate {
         struct perf_tool tool;
@@ -584,8 +585,8 @@ int cmd_annotate(int argc, const char **argv)
         data.path = input_name;
 
         annotate.session = perf_session__new(&data, false, &annotate.tool);
-        if (annotate.session == NULL)
-                return -1;
+        if (IS_ERR(annotate.session))
+                return PTR_ERR(annotate.session);
 
         annotate.has_br_stack = perf_header__has_feat(&annotate.session->header,
                                                       HEADER_BRANCH_STACK);
diff --git a/tools/perf/builtin-buildid-cache.c b/tools/perf/builtin-buildid-cache.c
index 1a69eb565dc0..39efa51d7fb3 100644
--- a/tools/perf/builtin-buildid-cache.c
+++ b/tools/perf/builtin-buildid-cache.c
@@ -28,6 +28,7 @@
 #include "util/util.h"
 #include "util/probe-file.h"
 #include <linux/string.h>
+#include <linux/err.h>
 
 static int build_id_cache__kcore_buildid(const char *proc_dir, char *sbuildid)
 {
@@ -422,8 +423,8 @@ int cmd_buildid_cache(int argc, const char **argv)
                 data.force = force;
 
                 session = perf_session__new(&data, false, NULL);
-                if (session == NULL)
-                        return -1;
+                if (IS_ERR(session))
+                        return PTR_ERR(session);
         }
 
         if (symbol__init(session ? &session->header.env : NULL) < 0)
diff --git a/tools/perf/builtin-buildid-list.c b/tools/perf/builtin-buildid-list.c
index 5a0d8b378cb5..e3ef75583514 100644
--- a/tools/perf/builtin-buildid-list.c
+++ b/tools/perf/builtin-buildid-list.c
@@ -18,6 +18,7 @@
 #include "util/symbol.h"
 #include "util/data.h"
 #include <errno.h>
+#include <linux/err.h>
 
 static int sysfs__fprintf_build_id(FILE *fp)
 {
@@ -65,8 +66,8 @@ static int perf_session__list_build_ids(bool force, bool with_hits)
                 goto out;
 
         session = perf_session__new(&data, false, &build_id__mark_dso_hit_ops);
-        if (session == NULL)
-                return -1;
+        if (IS_ERR(session))
+                return PTR_ERR(session);
 
         /*
          * We take all buildids when the file contains AUX area tracing data
diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index 61aaacc2aedd..3542b6ab9813 100644
--- a/tools/perf/builtin-c2c.c
+++ b/tools/perf/builtin-c2c.c
@@ -13,6 +13,7 @@
 #include <errno.h>
 #include <inttypes.h>
 #include <linux/compiler.h>
+#include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/stringify.h>
 #include <linux/zalloc.h>
@@ -2781,8 +2782,9 @@ static int perf_c2c__report(int argc, const char **argv)
         }
 
         session = perf_session__new(&data, 0, &c2c.tool);
-        if (session == NULL) {
-                pr_debug("No memory for session\n");
+        if (IS_ERR(session)) {
+                err = PTR_ERR(session);
+                pr_debug("Error creating perf session\n");
                 goto out;
         }
 
diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 827e4800d862..c37a78677955 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -23,6 +23,7 @@
 #include "util/time-utils.h"
 #include "util/annotate.h"
 #include "util/map.h"
+#include <linux/err.h>
 #include <linux/zalloc.h>
 #include <subcmd/pager.h>
 #include <subcmd/parse-options.h>
@@ -1153,9 +1154,9 @@ static int check_file_brstack(void)
 
         data__for_each_file(i, d) {
                 d->session = perf_session__new(&d->data, false, &pdiff.tool);
-                if (!d->session) {
+                if (IS_ERR(d->session)) {
                         pr_err("Failed to open %s\n", d->data.path);
-                        return -1;
+                        return PTR_ERR(d->session);
                 }
 
                 has_br_stack = perf_header__has_feat(&d->session->header,
@@ -1185,9 +1186,9 @@ static int __cmd_diff(void)
 
         data__for_each_file(i, d) {
                 d->session = perf_session__new(&d->data, false, &pdiff.tool);
-                if (!d->session) {
+                if (IS_ERR(d->session)) {
+                        ret = PTR_ERR(d->session);
                         pr_err("Failed to open %s\n", d->data.path);
-                        ret = -1;
                         goto out_delete;
                 }
 
diff --git a/tools/perf/builtin-evlist.c b/tools/perf/builtin-evlist.c
index 294494e60e48..60509ce4dd28 100644
--- a/tools/perf/builtin-evlist.c
+++ b/tools/perf/builtin-evlist.c
@@ -15,6 +15,7 @@
 #include "util/session.h"
 #include "util/data.h"
 #include "util/debug.h"
+#include <linux/err.h>
 
 static int __cmd_evlist(const char *file_name, struct perf_attr_details *details)
 {
@@ -28,8 +29,8 @@ static int __cmd_evlist(const char *file_name, struct perf_attr_details *details
         bool has_tracepoint = false;
 
         session = perf_session__new(&data, 0, NULL);
-        if (session == NULL)
-                return -1;
+        if (IS_ERR(session))
+                return PTR_ERR(session);
 
         evlist__for_each_entry(session->evlist, pos) {
                 perf_evsel__fprintf(pos, details, stdout);
diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index 23a76cf3846f..372ecb3e2c06 100644
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -23,6 +23,7 @@
 #include "util/symbol.h"
 #include "util/synthetic-events.h"
 #include "util/thread.h"
+#include <linux/err.h>
 
 #include <subcmd/parse-options.h>
 
@@ -835,8 +836,8 @@ int cmd_inject(int argc, const char **argv)
 
         data.path = inject.input_name;
         inject.session = perf_session__new(&data, true, &inject.tool);
-        if (inject.session == NULL)
-                return -1;
+        if (IS_ERR(inject.session))
+                return PTR_ERR(inject.session);
 
         if (zstd_init(&(inject.session->zstd_data), 0) < 0)
                 pr_warning("Decompression initialization failed.\n");
diff --git a/tools/perf/builtin-kmem.c b/tools/perf/builtin-kmem.c
index b5682beaad72..1e61e353f579 100644
--- a/tools/perf/builtin-kmem.c
+++ b/tools/perf/builtin-kmem.c
@@ -14,6 +14,7 @@
 #include "util/tool.h"
 #include "util/callchain.h"
 #include "util/time-utils.h"
+#include <linux/err.h>
 
 #include <subcmd/pager.h>
 #include <subcmd/parse-options.h>
@@ -1956,8 +1957,8 @@ int cmd_kmem(int argc, const char **argv)
         data.path = input_name;
 
         kmem_session = session = perf_session__new(&data, false, &perf_kmem);
-        if (session == NULL)
-                return -1;
+        if (IS_ERR(session))
+                return PTR_ERR(session);
 
         ret = -1;
 
diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
index 6e3e36658900..c4b22e1b0a40 100644
--- a/tools/perf/builtin-kvm.c
+++ b/tools/perf/builtin-kvm.c
@@ -33,6 +33,7 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 
+#include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
 #include <linux/time64.h>
@@ -1091,9 +1092,9 @@ static int read_events(struct perf_kvm_stat *kvm)
 
         kvm->tool = eops;
         kvm->session = perf_session__new(&file, false, &kvm->tool);
-        if (!kvm->session) {
+        if (IS_ERR(kvm->session)) {
                 pr_err("Initializing perf session failed\n");
-                return -1;
+                return PTR_ERR(kvm->session);
         }
 
         symbol__init(&kvm->session->header.env);
@@ -1446,8 +1447,8 @@ static int kvm_events_live(struct perf_kvm_stat *kvm,
          * perf session
          */
         kvm->session = perf_session__new(&data, false, &kvm->tool);
-        if (kvm->session == NULL) {
-                err = -1;
+        if (IS_ERR(kvm->session)) {
+                err = PTR_ERR(kvm->session);
                 goto out;
         }
         kvm->session->evlist = kvm->evlist;
diff --git a/tools/perf/builtin-lock.c b/tools/perf/builtin-lock.c
index 4c2b7f437cdf..474dfd59d7eb 100644
--- a/tools/perf/builtin-lock.c
+++ b/tools/perf/builtin-lock.c
@@ -30,6 +30,7 @@
 #include <linux/hash.h>
 #include <linux/kernel.h>
 #include <linux/zalloc.h>
+#include <linux/err.h>
 
 static struct perf_session *session;
 
@@ -872,9 +873,9 @@ static int __cmd_report(bool display_info)
         };
 
         session = perf_session__new(&data, false, &eops);
-        if (!session) {
+        if (IS_ERR(session)) {
                 pr_err("Initializing perf session failed\n");
-                return -1;
+                return PTR_ERR(session);
         }
 
         symbol__init(&session->header.env);
diff --git a/tools/perf/builtin-mem.c b/tools/perf/builtin-mem.c
index 27d2bde943a8..a13f5817d6fc 100644
--- a/tools/perf/builtin-mem.c
+++ b/tools/perf/builtin-mem.c
@@ -17,6 +17,7 @@
 #include "util/dso.h"
 #include "util/map.h"
 #include "util/symbol.h"
+#include <linux/err.h>
 
 #define MEM_OPERATION_LOAD      0x1
 #define MEM_OPERATION_STORE     0x2
@@ -249,8 +250,8 @@ static int report_raw_events(struct perf_mem *mem)
         struct perf_session *session = perf_session__new(&data, false,
                                                          &mem->tool);
 
-        if (session == NULL)
-                return -1;
+        if (IS_ERR(session))
+                return PTR_ERR(session);
 
         if (mem->cpu_list) {
                 ret = perf_session__cpu_bitmap(session, mem->cpu_list,
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 4bd11c918e73..3f66a49a997f 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -54,6 +54,7 @@
 #include <signal.h>
 #include <sys/mman.h>
 #include <sys/wait.h>
+#include <linux/err.h>
 #include <linux/string.h>
 #include <linux/time64.h>
 #include <linux/zalloc.h>
@@ -1354,9 +1355,9 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
         }
 
         session = perf_session__new(data, false, tool);
-        if (session == NULL) {
+        if (IS_ERR(session)) {
                 pr_err("Perf session creation failed.\n");
-                return -1;
+                return PTR_ERR(session);
         }
 
         fd = perf_data__fd(data);
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 3047e5169d9d..aae0e57c60fb 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -1269,8 +1269,8 @@ int cmd_report(int argc, const char **argv)
 
 repeat:
         session = perf_session__new(&data, false, &report.tool);
-        if (session == NULL)
-                return -1;
+        if (IS_ERR(session))
+                return PTR_ERR(session);
 
         ret = evswitch__init(&report.evswitch, session->evlist, stderr);
         if (ret)
diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c
index f0b828c201cc..079e67a36904 100644
--- a/tools/perf/builtin-sched.c
+++ b/tools/perf/builtin-sched.c
@@ -40,6 +40,7 @@
 #include <api/fs/fs.h>
 #include <perf/cpumap.h>
 #include <linux/time64.h>
+#include <linux/err.h>
 
 #include <linux/ctype.h>
 
@@ -1797,9 +1798,9 @@ static int perf_sched__read_events(struct perf_sched *sched)
         int rc = -1;
 
         session = perf_session__new(&data, false, &sched->tool);
-        if (session == NULL) {
-                pr_debug("No Memory for session\n");
-                return -1;
+        if (IS_ERR(session)) {
+                pr_debug("Error creating perf session");
+                return PTR_ERR(session);
         }
 
         symbol__init(&session->header.env);
@@ -2989,8 +2990,8 @@ static int perf_sched__timehist(struct perf_sched *sched)
         symbol_conf.use_callchain = sched->show_callchain;
 
         session = perf_session__new(&data, false, &sched->tool);
-        if (session == NULL)
-                return -ENOMEM;
+        if (IS_ERR(session))
+                return PTR_ERR(session);
 
         evlist = session->evlist;
 
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index e079b34201f2..a17a9306bdf6 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -52,6 +52,7 @@
 #include <unistd.h>
 #include <subcmd/pager.h>
 #include <perf/evlist.h>
+#include <linux/err.h>
 #include "util/record.h"
 #include "util/util.h"
 #include "perf.h"
@@ -3083,8 +3084,8 @@ int find_scripts(char **scripts_array, char **scripts_path_array, int num,
         int i = 0;
 
         session = perf_session__new(&data, false, NULL);
-        if (!session)
-                return -1;
+        if (IS_ERR(session))
+                return PTR_ERR(session);
 
         snprintf(scripts_path, MAXPATHLEN, "%s/scripts", get_argv_exec_path());
 
@@ -3754,8 +3755,8 @@ int cmd_script(int argc, const char **argv)
         }
 
         session = perf_session__new(&data, false, &script.tool);
-        if (session == NULL)
-                return -1;
+        if (IS_ERR(session))
+                return PTR_ERR(session);
 
         if (header || header_only) {
                 script.tool.show_feat_hdr = SHOW_FEAT_HEADER;
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 60cdd383af81..f7d13326b830 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -83,6 +83,7 @@
 #include <unistd.h>
 #include <sys/time.h>
 #include <sys/resource.h>
+#include <linux/err.h>
 
 #include <linux/ctype.h>
 #include <perf/evlist.h>
@@ -1436,9 +1437,9 @@ static int __cmd_record(int argc, const char **argv)
         }
 
         session = perf_session__new(data, false, NULL);
-        if (session == NULL) {
-                pr_err("Perf session creation failed.\n");
-                return -1;
+        if (IS_ERR(session)) {
+                pr_err("Perf session creation failed\n");
+                return PTR_ERR(session);
         }
 
         init_features(session);
@@ -1635,8 +1636,8 @@ static int __cmd_report(int argc, const char **argv)
         perf_stat.data.mode = PERF_DATA_MODE_READ;
 
         session = perf_session__new(&perf_stat.data, false, &perf_stat.tool);
-        if (session == NULL)
-                return -1;
+        if (IS_ERR(session))
+                return PTR_ERR(session);
 
         perf_stat.session  = session;
         stat_config.output = stderr;
diff --git a/tools/perf/builtin-timechart.c b/tools/perf/builtin-timechart.c
index e0e822695a29..9e84fae9b096 100644
--- a/tools/perf/builtin-timechart.c
+++ b/tools/perf/builtin-timechart.c
@@ -35,6 +35,7 @@
 #include "util/tool.h"
 #include "util/data.h"
 #include "util/debug.h"
+#include <linux/err.h>
 
 #ifdef LACKS_OPEN_MEMSTREAM_PROTOTYPE
 FILE *open_memstream(char **ptr, size_t *sizeloc);
@@ -1601,8 +1602,8 @@ static int __cmd_timechart(struct timechart *tchart, const char *output_name)
                                                          &tchart->tool);
         int ret = -EINVAL;
 
-        if (session == NULL)
-                return -1;
+        if (IS_ERR(session))
+                return PTR_ERR(session);
 
         symbol__init(&session->header.env);
 
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index b052470f89b4..8da3c939e6b0 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -77,6 +77,7 @@
 #include <linux/stringify.h>
 #include <linux/time64.h>
 #include <linux/types.h>
+#include <linux/err.h>
 
 #include <linux/ctype.h>
 
@@ -1672,8 +1673,8 @@ int cmd_top(int argc, const char **argv)
         }
 
         top.session = perf_session__new(NULL, false, NULL);
-        if (top.session == NULL) {
-                status = -1;
+        if (IS_ERR(top.session)) {
+                status = PTR_ERR(top.session);
                 goto out_delete_evlist;
         }
 
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index f0f735093e21..a292658b4232 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -3585,8 +3585,8 @@ static int trace__replay(struct trace *trace)
         trace->multiple_threads = true;
 
         session = perf_session__new(&data, false, &trace->tool);
-        if (session == NULL)
-                return -1;
+        if (IS_ERR(session))
+                return PTR_ERR(session);
 
         if (trace->opts.target.pid)
                 symbol_conf.pid_list_str = strdup(trace->opts.target.pid);
diff --git a/tools/perf/tests/topology.c b/tools/perf/tests/topology.c
index 7d845d913d7d..4a800499d7c3 100644
--- a/tools/perf/tests/topology.c
+++ b/tools/perf/tests/topology.c
@@ -8,6 +8,7 @@
 #include "session.h"
 #include "evlist.h"
 #include "debug.h"
+#include <linux/err.h>
 
 #define TEMPL "/tmp/perf-test-XXXXXX"
 #define DATA_SIZE       10
@@ -39,7 +40,7 @@ static int session_write_header(char *path)
         };
 
         session = perf_session__new(&data, false, NULL);
-        TEST_ASSERT_VAL("can't get session", session);
+        TEST_ASSERT_VAL("can't get session", !IS_ERR(session));
 
         session->evlist = perf_evlist__new_default();
         TEST_ASSERT_VAL("can't get evlist", session->evlist);
@@ -70,7 +71,7 @@ static int check_cpu_topology(char *path, struct perf_cpu_map *map)
         int i;
 
         session = perf_session__new(&data, false, NULL);
-        TEST_ASSERT_VAL("can't get session", session);
+        TEST_ASSERT_VAL("can't get session", !IS_ERR(session));
 
         /* On platforms with large numbers of CPUs process_cpu_topology()
          * might issue an error while reading the perf.data file section
diff --git a/tools/perf/util/data-convert-bt.c b/tools/perf/util/data-convert-bt.c
index 0c268449959c..dbc772bfb04e 100644
--- a/tools/perf/util/data-convert-bt.c
+++ b/tools/perf/util/data-convert-bt.c
@@ -30,6 +30,7 @@
 #include "machine.h"
 #include "config.h"
 #include <linux/ctype.h>
+#include <linux/err.h>
 
 #define pr_N(n, fmt, ...) \
         eprintf(n, debug_data_convert, fmt, ##__VA_ARGS__)
@@ -1619,8 +1620,10 @@ int bt_convert__perf2ctf(const char *input, const char *path,
         err = -1;
         /* perf.data session */
         session = perf_session__new(&data, 0, &c.tool);
-        if (!session)
+        if (IS_ERR(session)) {
+                err = PTR_ERR(session);
                 goto free_writer;
+        }
 
         if (c.queue_size) {
                 ordered_events__set_alloc_size(&session->ordered_events,
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 58b5bc34ba12..a621c73bad42 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -34,6 +34,7 @@
 #include "../perf.h"
 #include "arch/common.h"
 #include <internal/lib.h>
+#include <linux/err.h>
 
 #ifdef HAVE_ZSTD_SUPPORT
 static int perf_session__process_compressed_event(struct perf_session *session,
@@ -187,6 +188,7 @@ static int ordered_events__deliver_event(struct ordered_events *oe,
 struct perf_session *perf_session__new(struct perf_data *data,
                                        bool repipe, struct perf_tool *tool)
 {
+        int ret = -ENOMEM;
         struct perf_session *session = zalloc(sizeof(*session));
 
         if (!session)
@@ -201,13 +203,15 @@ struct perf_session *perf_session__new(struct perf_data *data,
 
         perf_env__init(&session->header.env);
         if (data) {
-                if (perf_data__open(data))
+                ret = perf_data__open(data);
+                if (ret < 0)
                         goto out_delete;
 
                 session->data = data;
 
                 if (perf_data__is_read(data)) {
-                        if (perf_session__open(session) < 0)
+                        ret = perf_session__open(session);
+                        if (ret < 0)
                                 goto out_delete;
 
                         /*
@@ -222,8 +226,11 @@ struct perf_session *perf_session__new(struct perf_data *data,
                         perf_evlist__init_trace_event_sample_raw(session->evlist);
 
                         /* Open the directory data. */
-                        if (data->is_dir && perf_data__open_dir(data))
+                        if (data->is_dir) {
+                                ret = perf_data__open_dir(data);
+                        if (ret)
                                 goto out_delete;
+                        }
                 }
         } else  {
                 session->machines.host.env = &perf_env;
@@ -256,7 +263,7 @@ struct perf_session *perf_session__new(struct perf_data *data,
  out_delete:
         perf_session__delete(session);
  out:
-        return NULL;
+        return ERR_PTR(ret);
 }
 
 static void perf_session__delete_threads(struct perf_session *session)