[BUG] reporting stuck on s390 in dso__split_kallsyms_for_kcore

[Jiri Olsa <jolsa@redhat.com>]

hi,
I'm getting stuck buildid-list command on s390

seems like the kcore code gets stuck with inseting
into rbtree while iterating it..

I was able to fix it with patch below, bu I'm not sure it's the
correct fix because the kcore maps magic is beyond me so far ;-)

please check attached backtrace and patch 


(gdb) r buildid-list -i perf.data --with-hits
Starting program: /root/linux/tools/perf/./perf buildid-list -i perf.data --with-hits
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
Detaching after fork from child process 56723.
^C
Program received signal SIGINT, Interrupt.
rb_next (node=0x81573930, node@entry=0x81551840) at ../lib/rbtree.c:451
451                             node=node->rb_left;
Missing separate debuginfos, use: debuginfo-install audit-libs-2.4.1-5.el7.s390x bzip2-libs-1.0.6-13.el7.s390x elfutils-libelf-0.163-3.el7.s390x elfutils-libs-0.163-3.el7.s390x glibc-2.17-105.el7.s390x nss-softokn-freebl-3.16.2.3-13.el7_1.s390x perl-libs-5.16.3-286.el7.s390x python-libs-2.7.5-34.el7.s390x slang-2.2.4-11.el7.s390x xz-libs-5.1.2-12alpha.el7.s390x zlib-1.2.7-15.el7.s390x
(gdb) bt
#0  rb_next (node=0x81573930, node@entry=0x81551840) at ../lib/rbtree.c:451
#1  0x00000000800a7da0 in dso__split_kallsyms_for_kcore (dso=dso@entry=0x812e69c0, map=map@entry=0x812e6fb0, filter=filter@entry=0x0)
    at util/symbol.c:668
#2  0x00000000800a9ac6 in dso__load_kallsyms (dso=dso@entry=0x812e69c0, filename=filename@entry=0x81353030 "/proc/kallsyms", 
    map=map@entry=0x812e6fb0, filter=filter@entry=0x0) at util/symbol.c:1289
#3  0x00000000800aa0c4 in dso__load_kernel_sym (dso=dso@entry=0x812e69c0, map=map@entry=0x812e6fb0, filter=filter@entry=0x0)
    at util/symbol.c:1783
#4  0x00000000800aa208 in dso__load (dso=0x812e69c0, map=map@entry=0x812e6fb0, filter=filter@entry=0x0) at util/symbol.c:1420
#5  0x00000000800bb2aa in map__load (map=0x812e6fb0, filter=0x0) at util/map.c:289
#6  0x0000000080087c9e in thread__find_addr_map (thread=<optimized out>, cpumode=cpumode@entry=1 '\001', type=type@entry=MAP__FUNCTION, 
    addr=<optimized out>, al=al@entry=0x3ffffffe118) at util/event.c:969
#7  0x0000000080081908 in build_id__mark_dso_hit (tool=<optimized out>, event=0x3fffd5aa568, sample=0x3ffffffe410, evsel=<optimized out>, 
    machine=<optimized out>) at util/build-id.c:41
#8  0x00000000800bdfec in perf_evlist__deliver_sample (evlist=evlist@entry=0x812e5d60, 
    tool=tool@entry=0x8024b240 <build_id__mark_dso_hit_ops>, event=event@entry=0x3fffd5aa568, sample=sample@entry=0x3ffffffe410, 
    evsel=evsel@entry=0x812e6770, machine=0x812e5ab8) at util/session.c:1039
#9  0x00000000800be156 in machines__deliver_event (machines=machines@entry=0x812e5ab8, evlist=0x812e5d60, 
    event=event@entry=0x3fffd5aa568, sample=sample@entry=0x3ffffffe410, tool=tool@entry=0x8024b240 <build_id__mark_dso_hit_ops>, 
    file_offset=136552) at util/session.c:1076
#10 0x00000000800be3f2 in perf_session__deliver_event (session=session@entry=0x812e59e0, event=event@entry=0x3fffd5aa568, 
    sample=sample@entry=0x3ffffffe410, tool=tool@entry=0x8024b240 <build_id__mark_dso_hit_ops>, file_offset=<optimized out>)
    at util/session.c:1133
#11 0x00000000800c0146 in perf_session__process_event (session=session@entry=0x812e59e0, event=event@entry=0x3fffd5aa568, 
    file_offset=file_offset@entry=136552) at util/session.c:1298
#12 0x00000000800c0746 in __perf_session__process_events (session=session@entry=0x812e59e0, data_offset=<optimized out>, 
    data_size=<optimized out>, file_size=1164232, file_size@entry=1166128) at util/session.c:1633
#13 0x00000000800c0c2c in perf_session__process_events (session=session@entry=0x812e59e0) at util/session.c:1683
#14 0x000000008002ae5e in perf_session__list_build_ids (force=<optimized out>, with_hits=true) at builtin-buildid-list.c:82
#15 0x000000008002b078 in cmd_buildid_list (argc=<optimized out>, argv=<optimized out>, prefix=<optimized out>)
    at builtin-buildid-list.c:115
#16 0x000000008007c71a in run_builtin (p=p@entry=0x8024aab8 <commands+24>, argc=argc@entry=4, argv=0x3fffffff090) at perf.c:385
#17 0x000000008007c95e in handle_internal_command (argc=<optimized out>, argv=<optimized out>) at perf.c:445
#18 0x000000008007c9e4 in run_argv (argcp=argcp@entry=0x3ffffffedd4, argv=argv@entry=0x3ffffffedc8) at perf.c:489
#19 0x000000008007cca2 in main (argc=4, argv=0x3fffffff090) at perf.c:606


thanks,
jirka


---
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index e7bf0c4..b0d2fb2 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -680,7 +680,7 @@ static int dso__split_kallsyms_for_kcore(struct dso *dso, struct map *map,
 			pos->start -= curr_map->start - curr_map->pgoff;
 			if (pos->end)
 				pos->end -= curr_map->start - curr_map->pgoff;
-			if (curr_map != map) {
+			if (curr_map->dso != map->dso) {
 				rb_erase_init(&pos->rb_node, root);
 				symbols__insert(
 					&curr_map->dso->symbols[curr_map->type],