path: root/tools
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authorThomas Richter <tmricht@linux.ibm.com>2020-01-20 14:20:09 +0100
committerArnaldo Carvalho de Melo <acme@redhat.com>2020-01-30 11:55:02 +0100
commit0dd1979f7f9981dcc5c497e68390f208580032ae (patch)
tree3b5d1bc1a5d622f5211f670ff33a62f6e0d8be1e /tools
parentperf parse: Copy string to perf_evsel_config_term (diff)
perf test: Fix test case Merge cpu map
Commit a2408a70368a ("perf evlist: Maintain evlist->all_cpus") introduces a test case for cpumap merge operation, see functions perf_cpu_map__merge() and test__cpu_map_merge(). The test case fails on s390 with this error message: [root@m35lp76 perf]# ./perf test -Fvvvvv 52 52: Merge cpu map : --- start --- cpumask list: 1-2,4-5,7 perf: /root/linux/tools/include/linux/refcount.h:131:\ refcount_sub_and_test: Assertion `!(new > val)' failed. Aborted (core dumped) [root@m35lp76 perf]# The root cause is in the function test__cpu_map_merge(): It creates two cpu_maps named 'a' and 'b': struct perf_cpu_map *a = perf_cpu_map__new("4,2,1"); struct perf_cpu_map *b = perf_cpu_map__new("4,5,7"); and creates a third map named 'c' which is the result of the merge of maps a and b: struct perf_cpu_map *c = perf_cpu_map__merge(a, b); After some verifaction of the merged cpu_map all three of them are have their reference count reduced and are freed: perf_cpu_map__put(a); (1) perf_cpu_map__put(b); perf_cpu_map__put(c); The release of perf_cpu_map__put(a) is wrong. The map is already released and free'ed as part of the function perf_cpu_map__merge(struct perf_cpu_map *orig, | struct perf_cpu_map *other) +--> perf_cpu_map__put(orig); | +--> cpu_map__delete(orig) At the end perf_cpu_map_put() is called for map 'orig' alias 'a' and since the reference count is 1, the map is deleted, as can be seen by the following gdb trace: (gdb) where #0 tcache_put (tc_idx=0, chunk=0x156cc30) at malloc.c:2940 #1 _int_free (av=0x3fffd49ee80 <main_arena>, p=0x156cc30, have_lock=<optimized out>) at malloc.c:4222 #2 0x00000000012d5e78 in cpu_map__delete (map=0x156cc40) at cpumap.c:31 #3 0x00000000012d5f7a in perf_cpu_map__put (map=0x156cc40) at cpumap.c:45 #4 0x00000000012d723a in perf_cpu_map__merge (orig=0x156cc40, other=0x156cc60) at cpumap.c:343 #5 0x000000000110cdd0 in test__cpu_map_merge ( test=0x14ea6c8 <generic_tests+2856>, subtest=-1) at tests/cpumap.c:128 Thus the perf_cpu_map__put(a) (see (1) above) frees map 'a' a second time and causes the failure. Fix this be removing that function call. Output after: [root@m35lp76 perf]# ./perf test -Fvvvvv 52 52: Merge cpu map : --- start --- cpumask list: 1-2,4-5,7 ---- end ---- Merge cpu map: Ok [root@m35lp76 perf]# Signed-off-by: Thomas Richter <tmricht@linux.ibm.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: sumanthk@linux.ibm.com Link: http://lore.kernel.org/lkml/20200120132011.64698-1-tmricht@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
1 files changed, 0 insertions, 1 deletions
diff --git a/tools/perf/tests/cpumap.c b/tools/perf/tests/cpumap.c
index 4ac56741ac5f..29c793ac7d10 100644
--- a/tools/perf/tests/cpumap.c
+++ b/tools/perf/tests/cpumap.c
@@ -131,7 +131,6 @@ int test__cpu_map_merge(struct test *test __maybe_unused, int subtest __maybe_un
TEST_ASSERT_VAL("failed to merge map: bad nr", c->nr == 5);
cpu_map__snprint(c, buf, sizeof(buf));
TEST_ASSERT_VAL("failed to merge map: bad result", !strcmp(buf, "1-2,4-5,7"));
- perf_cpu_map__put(a);
return 0;