perf callchain: Fix segfault in thread__resolve_callchain_sample()

Do not dereference 'chain' when it is NULL.

  $ perf record -e intel_pt//u -e branch-misses:u uname
  $ perf report --itrace=l --branch-history
  perf: Segmentation fault

Fixes: e9024d519d ("perf callchain: Honour the ordering of PERF_CONTEXT_{USER,KERNEL,etc}")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20191114142538.4097-1-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Adrian Hunter 2019-11-14 16:25:38 +02:00 коммит произвёл Arnaldo Carvalho de Melo
Родитель a7c2b572e2
Коммит aceb98261e
1 изменённых файлов: 1 добавлений и 1 удалений

Просмотреть файл

@ -2385,7 +2385,7 @@ static int thread__resolve_callchain_sample(struct thread *thread,
} }
check_calls: check_calls:
if (callchain_param.order != ORDER_CALLEE) { if (chain && callchain_param.order != ORDER_CALLEE) {
err = find_prev_cpumode(chain, thread, cursor, parent, root_al, err = find_prev_cpumode(chain, thread, cursor, parent, root_al,
&cpumode, chain->nr - first_call); &cpumode, chain->nr - first_call);
if (err) if (err)