From: Thomas Richter Date: Mon, 28 May 2018 07:36:57 +0000 (+0200) Subject: perf test: "Session topology" dumps core on s390 X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=d121109100bda84bbbb199dab97f9d56432ab235;p=openwrt%2Fstaging%2Fblogic.git perf test: "Session topology" dumps core on s390 The "perf test Session topology" entry fails with core dump on s390. The root cause is a NULL pointer dereference in function check_cpu_topology() line 76 (or line 82 without -v). The session->header.env.cpu variable is NULL because on s390 function process_cpu_topology() returns with error: socket_id number is too big. You may need to upgrade the perf tool. and releases the env.cpu variable via zfree() and sets it to NULL. Here is the gdb output: (gdb) n 76 pr_debug("CPU %d, core %d, socket %d\n", i, (gdb) n Program received signal SIGSEGV, Segmentation fault. 0x00000000010f4d9e in check_cpu_topology (path=0x3ffffffd6c8 "/tmp/perf-test-J6CHMa", map=0x14a1740) at tests/topology.c:76 76 pr_debug("CPU %d, core %d, socket %d\n", i, (gdb) Make sure the env.cpu variable is not used when its NULL. Test for NULL pointer and return TEST_SKIP if so. Output before: [root@p23lp27 perf]# ./perf test -F 39 39: Session topology :Segmentation fault (core dumped) [root@p23lp27 perf]# Output after: [root@p23lp27 perf]# ./perf test -vF 39 39: Session topology : --- start --- templ file: /tmp/perf-test-Ajx59D socket_id number is too big.You may need to upgrade the perf tool. ---- end ---- Session topology: Skip [root@p23lp27 perf]# Signed-off-by: Thomas Richter Cc: Heiko Carstens Cc: Hendrik Brueckner Cc: Martin Schwidefsky Link: http://lkml.kernel.org/r/20180528073657.11743-1-tmricht@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo --- diff --git a/tools/perf/tests/topology.c b/tools/perf/tests/topology.c index 17cb1bb3448c..40e30a26b23c 100644 --- a/tools/perf/tests/topology.c +++ b/tools/perf/tests/topology.c @@ -70,6 +70,27 @@ static int check_cpu_topology(char *path, struct cpu_map *map) session = perf_session__new(&data, false, NULL); TEST_ASSERT_VAL("can't get session", session); + /* On platforms with large numbers of CPUs process_cpu_topology() + * might issue an error while reading the perf.data file section + * HEADER_CPU_TOPOLOGY and the cpu_topology_map pointed to by member + * cpu is a NULL pointer. + * Example: On s390 + * CPU 0 is on core_id 0 and physical_package_id 6 + * CPU 1 is on core_id 1 and physical_package_id 3 + * + * Core_id and physical_package_id are platform and architecture + * dependend and might have higher numbers than the CPU id. + * This actually depends on the configuration. + * + * In this case process_cpu_topology() prints error message: + * "socket_id number is too big. You may need to upgrade the + * perf tool." + * + * This is the reason why this test might be skipped. + */ + if (!session->header.env.cpu) + return TEST_SKIP; + for (i = 0; i < session->header.env.nr_cpus_avail; i++) { if (!cpu_map__has(map, i)) continue; @@ -95,7 +116,7 @@ int test__session_topology(struct test *test __maybe_unused, int subtest __maybe { char path[PATH_MAX]; struct cpu_map *map; - int ret = -1; + int ret = TEST_FAIL; TEST_ASSERT_VAL("can't get templ file", !get_temp(path)); @@ -110,12 +131,9 @@ int test__session_topology(struct test *test __maybe_unused, int subtest __maybe goto free_path; } - if (check_cpu_topology(path, map)) - goto free_map; - ret = 0; - -free_map: + ret = check_cpu_topology(path, map); cpu_map__put(map); + free_path: unlink(path); return ret;