From: Adrian Hunter <adrian.hunter@intel.com>

Date: Thu, 14 Nov 2019 16:25:38 +0200

Subject: perf callchain: Fix segfault in thread__resolve_callchain_sample()

Git-commit: aceb98261ea7d9fe38f9c140c5531f0b13623832

Patch-mainline: v5.5-rc1

References: git-fixes

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Do not dereference 'chain' when it is NULL.

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  $ perf record -e intel_pt//u -e branch-misses:u uname

  $ perf report --itrace=l --branch-history

  perf: Segmentation fault

​

Fixes: e9024d519d89 ("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>

Signed-off-by: Tony Jones <tonyj@suse.de>

---

 tools/perf/util/machine.c | 2 +-

 1 file changed, 1 insertion(+), 1 deletion(-)

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diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c

index 7d2e211e376c..71ee078d30f4 100644

--- a/tools/perf/util/machine.c

+++ b/tools/perf/util/machine.c

@@ -2385,7 +2385,7 @@ static int thread__resolve_callchain_sample(struct thread *thread,

    }

 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,

                    &cpumode, chain->nr - first_call);

        if (err)

​

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