By calling maps__insert we assume to get 2 references on the map, which we relese within maps__remove call.
However if there's already same map name, we currently don't bump the reference and can crash, like: Program received signal SIGABRT, Aborted. 0x00007ffff75e60f5 in raise () from /lib64/libc.so.6 (gdb) bt #0 0x00007ffff75e60f5 in raise () from /lib64/libc.so.6 #1 0x00007ffff75d0895 in abort () from /lib64/libc.so.6 #2 0x00007ffff75d0769 in __assert_fail_base.cold () from /lib64/libc.so.6 #3 0x00007ffff75de596 in __assert_fail () from /lib64/libc.so.6 #4 0x00000000004fc006 in refcount_sub_and_test (i=1, r=0x1224e88) at tools/include/linux/refcount.h:131 #5 refcount_dec_and_test (r=0x1224e88) at tools/include/linux/refcount.h:148 #6 map__put (map=0x1224df0) at util/map.c:299 #7 0x00000000004fdb95 in __maps__remove (map=0x1224df0, maps=0xb17d80) at util/map.c:953 #8 maps__remove (maps=0xb17d80, map=0x1224df0) at util/map.c:959 #9 0x00000000004f7d8a in map_groups__remove (map=<optimized out>, mg=<optimized out>) at util/map_groups.h:65 #10 machine__process_ksymbol_unregister (sample=<optimized out>, event=0x7ffff7279670, machine=<optimized out>) at util/machine.c:728 #11 machine__process_ksymbol (machine=<optimized out>, event=0x7ffff7279670, sample=<optimized out>) at util/machine.c:741 #12 0x00000000004fffbb in perf_session__deliver_event (session=0xb11390, event=0x7ffff7279670, tool=0x7fffffffc7b0, file_offset=13936) at util/session.c:1362 #13 0x00000000005039bb in do_flush (show_progress=false, oe=0xb17e80) at util/ordered-events.c:243 #14 __ordered_events__flush (oe=0xb17e80, how=OE_FLUSH__ROUND, timestamp=<optimized out>) at util/ordered-events.c:322 #15 0x00000000005005e4 in perf_session__process_user_event (session=session@entry=0xb11390, event=event@entry=0x7ffff72a4af8, ... Adding the map on the list and getting the reference event if we find the map with same name. Cc: Song Liu <songliubrav...@fb.com> Link: http://lkml.kernel.org/n/tip-38t1ihcy32lvu4xfpm0p7...@git.kernel.org Signed-off-by: Jiri Olsa <jo...@kernel.org> --- tools/perf/util/map.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c index 28d484ef74ae..ee71efb9db62 100644 --- a/tools/perf/util/map.c +++ b/tools/perf/util/map.c @@ -926,10 +926,8 @@ static void __maps__insert_name(struct maps *maps, struct map *map) rc = strcmp(m->dso->short_name, map->dso->short_name); if (rc < 0) p = &(*p)->rb_left; - else if (rc > 0) - p = &(*p)->rb_right; else - return; + p = &(*p)->rb_right; } rb_link_node(&map->rb_node_name, parent, p); rb_insert_color(&map->rb_node_name, &maps->names); -- 2.17.2
