[PATCH 5.4 49/76] perf intel-pt: Fix CPU too large error

Greg Kroah-Hartman
2021-01-18T11:50:29Z

From: Adrian Hunter <adrian.hunter@intel.com>

commit 5501e9229a80d95a1ea68609f44c447a75d23ed5 upstream.

In some cases, the number of cpus (nr_cpus_online) is confused with the
maximum cpu number (nr_cpus_avail), which results in the error in the
example below:

Example on system with 8 cpus:

Before:
# echo 0 > /sys/devices/system/cpu/cpu2/online
# ./perf record --kcore -e intel_pt// taskset --cpu-list 7 uname
Linux
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.147 MB perf.data ]
# ./perf script --itrace=e
Requested CPU 7 too large. Consider raising MAX_NR_CPUS
0x25908 [0x8]: failed to process type: 68 [Invalid argument]

After:
# ./perf script --itrace=e
#

Fixes: 8c7274691f0d ("perf machine: Replace MAX_NR_CPUS with perf_env::nr_cpus_online")
Fixes: 7df4e36a4785 ("perf session: Replace MAX_NR_CPUS with perf_env::nr_cpus_online")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Kan Liang <kan.liang@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lore.kernel.org/lkml/20210107174159.24897-1-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
tools/perf/util/machine.c | 4 ++--
tools/perf/util/session.c | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)

--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -2587,7 +2587,7 @@ int machines__for_each_thread(struct mac

pid_t machine__get_current_tid(struct machine *machine, int cpu)
{
- int nr_cpus = min(machine->env->nr_cpus_online, MAX_NR_CPUS);
+ int nr_cpus = min(machine->env->nr_cpus_avail, MAX_NR_CPUS);

if (cpu < 0 || cpu >= nr_cpus || !machine->current_tid)
return -1;
@@ -2599,7 +2599,7 @@ int machine__set_current_tid(struct mach
pid_t tid)
{
struct thread *thread;
- int nr_cpus = min(machine->env->nr_cpus_online, MAX_NR_CPUS);
+ int nr_cpus = min(machine->env->nr_cpus_avail, MAX_NR_CPUS);

if (cpu < 0)
return -EINVAL;
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -2314,7 +2314,7 @@ int perf_session__cpu_bitmap(struct perf
{
int i, err = -1;
struct perf_cpu_map *map;
- int nr_cpus = min(session->header.env.nr_cpus_online, MAX_NR_CPUS);
+ int nr_cpus = min(session->header.env.nr_cpus_avail, MAX_NR_CPUS);

for (i = 0; i < PERF_TYPE_MAX; ++i) {
struct evsel *evsel;