[PATCH AUTOSEL 4.19 08/65] perf tools: Handle TOPOLOGY headers with no CPU

Sasha Levin
2019-02-23T21:27:39Z

From: Stephane Eranian <eranian@google.com>

[ Upstream commit 1497e804d1a6e2bd9107ddf64b0310449f4673eb ]

This patch fixes an issue in cpumap.c when used with the TOPOLOGY
header. In some configurations, some NUMA nodes may have no CPU (empty
cpulist). Yet a cpumap map must be created otherwise perf abort with an
error. This patch handles this case by creating a dummy map.

Before:

$ perf record -o - -e cycles noploop 2 | perf script -i -
0x6e8 [0x6c]: failed to process type: 80

After:

$ perf record -o - -e cycles noploop 2 | perf script -i -
noploop for 2 seconds

Signed-off-by: Stephane Eranian <eranian@google.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1547885559-1657-1-git-send-email-eranian@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/perf/util/cpumap.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c
index 1ccbd33420694..383674f448fcd 100644
--- a/tools/perf/util/cpumap.c
+++ b/tools/perf/util/cpumap.c
@@ -134,7 +134,12 @@ struct cpu_map *cpu_map__new(const char *cpu_list)
if (!cpu_list)
return cpu_map__read_all_cpu_map();

- if (!isdigit(*cpu_list))
+ /*
+ * must handle the case of empty cpumap to cover
+ * TOPOLOGY header for NUMA nodes with no CPU
+ * ( e.g., because of CPU hotplug)
+ */
+ if (!isdigit(*cpu_list) && *cpu_list != '\0')
goto out;

while (isdigit(*cpu_list)) {
@@ -181,8 +186,10 @@ struct cpu_map *cpu_map__new(const char *cpu_list)

if (nr_cpus > 0)
cpus = cpu_map__trim_new(nr_cpus, tmp_cpus);
- else
+ else if (*cpu_list != '\0')
cpus = cpu_map__default_new();
+ else
+ cpus = cpu_map__dummy_new();
invalid:
free(tmp_cpus);
out:
--
2.19.1