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authorJan Stancek <jstancek@redhat.com>2017-02-17 12:10:25 +0100
committerArnaldo Carvalho de Melo <acme@redhat.com>2017-02-17 12:37:04 -0300
commit43db2843a4a41cc8cdb6ab696639aeee1f4d5062 (patch)
treee6b24505f0a6c455fa2e6026e77b2f7d3f84864c /tools
parent92a7e1278005b6bb3459affc50b2b6e2464e7e7c (diff)
downloadlinux-43db2843a4a41cc8cdb6ab696639aeee1f4d5062.tar.gz
perf header: Make build_cpu_topology skip offline/absent CPUs
When build_cpu_topo() encounters offline/absent CPUs, it fails to find any sysfs entries and returns failure. This leads to build_cpu_topology() and write_cpu_topology() failing as well. Because HEADER_CPU_TOPOLOGY has not been written, read leaves cpu_topology_map NULL and we get NULL ptr deref at: ... cmd_test __cmd_test test_and_print run_test test_session_topology check_cpu_topology 36: Session topology : --- start --- test child forked, pid 14902 templ file: /tmp/perf-test-4CKocW failed to write feature HEADER_CPU_TOPOLOGY perf: Segmentation fault Obtained 9 stack frames. ./perf(sighandler_dump_stack+0x41) [0x5095f1] /lib64/libc.so.6(+0x35250) [0x7f4b7c3c9250] ./perf(test_session_topology+0x1db) [0x490ceb] ./perf() [0x475b68] ./perf(cmd_test+0x5b9) [0x4763c9] ./perf() [0x4945a3] ./perf(main+0x69f) [0x427e8f] /lib64/libc.so.6(__libc_start_main+0xf5) [0x7f4b7c3b5b35] ./perf() [0x427fb9] test child interrupted ---- end ---- Session topology: FAILED! This patch makes build_cpu_topology() skip offline/absent CPUs, by checking their presence against cpu_map built from online CPUs. Signed-off-by: Jan Stancek <jstancek@redhat.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/a271b770175524f4961d4903af33798358a4a518.1487146877.git.jstancek@redhat.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/util/header.c19
1 files changed, 16 insertions, 3 deletions
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 3d12c16..1222f6c 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -505,24 +505,31 @@ static void free_cpu_topo(struct cpu_topo *tp)
static struct cpu_topo *build_cpu_topology(void)
{
- struct cpu_topo *tp;
+ struct cpu_topo *tp = NULL;
void *addr;
u32 nr, i;
size_t sz;
long ncpus;
int ret = -1;
+ struct cpu_map *map;
ncpus = sysconf(_SC_NPROCESSORS_CONF);
if (ncpus < 0)
return NULL;
+ /* build online CPU map */
+ map = cpu_map__new(NULL);
+ if (map == NULL) {
+ pr_debug("failed to get system cpumap\n");
+ return NULL;
+ }
+
nr = (u32)(ncpus & UINT_MAX);
sz = nr * sizeof(char *);
-
addr = calloc(1, sizeof(*tp) + 2 * sz);
if (!addr)
- return NULL;
+ goto out_free;
tp = addr;
tp->cpu_nr = nr;
@@ -532,10 +539,16 @@ static struct cpu_topo *build_cpu_topology(void)
tp->thread_siblings = addr;
for (i = 0; i < nr; i++) {
+ if (!cpu_map__has(map, i))
+ continue;
+
ret = build_cpu_topo(tp, i);
if (ret < 0)
break;
}
+
+out_free:
+ cpu_map__put(map);
if (ret) {
free_cpu_topo(tp);
tp = NULL;