From a55e5663761366fb883f6f25375dd68bc958b9db Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Wed, 17 Feb 2016 10:57:19 -0300 Subject: [PATCH] perf evlist: Reference count the cpu and thread maps at set_maps() We were dropping the reference we possibly held but not obtaining one for the new maps, which we will drop at perf_evlist__delete(), fix it. This was caught by Steven Noonan in some of the machines which would produce this output when caught by glibc debug mechanisms: $ sudo perf test 21 21: Test object code reading :*** Error in `perf': corrupted double-linked list: 0x00000000023ffcd0 *** ======= Backtrace: ========= /usr/lib/libc.so.6(+0x72055)[0x7f25be0f3055] /usr/lib/libc.so.6(+0x779b6)[0x7f25be0f89b6] /usr/lib/libc.so.6(+0x7a0ed)[0x7f25be0fb0ed] /usr/lib/libc.so.6(__libc_calloc+0xba)[0x7f25be0fceda] perf(parse_events_lex_init_extra+0x38)[0x4cfff8] perf(parse_events+0x55)[0x4a0615] perf(perf_evlist__config+0xcf)[0x4eeb2f] perf[0x479f82] perf(test__code_reading+0x1e)[0x47ad4e] perf(cmd_test+0x5dd)[0x46452d] perf[0x47f4e3] perf(main+0x603)[0x42c723] /usr/lib/libc.so.6(__libc_start_main+0xf0)[0x7f25be0a1610] perf(_start+0x29)[0x42c859] Further investigation using valgrind led to the reference count imbalance fixed in this patch. Reported-and-Tested-by: Steven Noonan Report-Link: http://lkml.kernel.org/r/CAKbGBLjC2Dx5vshxyGmQkcD+VwiAQLbHoXA9i7kvRB2-2opHZQ@mail.gmail.com Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Fixes: f30a79b012e5 ("perf tools: Add reference counting for cpu_map object") Link: http://lkml.kernel.org/n/tip-j0u1bdhr47sa511sgg76kb8h@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evlist.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index d81f13de2476..a7eb0eae9938 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -1181,12 +1181,12 @@ void perf_evlist__set_maps(struct perf_evlist *evlist, struct cpu_map *cpus, */ if (cpus != evlist->cpus) { cpu_map__put(evlist->cpus); - evlist->cpus = cpus; + evlist->cpus = cpu_map__get(cpus); } if (threads != evlist->threads) { thread_map__put(evlist->threads); - evlist->threads = threads; + evlist->threads = thread_map__get(threads); } perf_evlist__propagate_maps(evlist); -- 2.11.0