From: Leo Yan leo.yan@linaro.org
[ Upstream commit 35bb59c10a6d0578806dd500477dae9cb4be344e ]
Robert Walker reported a segmentation fault is observed when process CoreSight trace data; this issue can be easily reproduced by the command 'perf report --itrace=i1000i' for decoding tracing data.
If neither the 'b' flag (synthesize branches events) nor 'l' flag (synthesize last branch entries) are specified to option '--itrace', cs_etm_queue::prev_packet will not been initialised. After merging the code to support exception packets and sample flags, there introduced a number of uses of cs_etm_queue::prev_packet without checking whether it is valid, for these cases any accessing to uninitialised prev_packet will cause crash.
As cs_etm_queue::prev_packet is used more widely now and it's already hard to follow which functions have been called in a context where the validity of cs_etm_queue::prev_packet has been checked, this patch always allocates memory for cs_etm_queue::prev_packet.
Reported-by: Robert Walker robert.walker@arm.com Suggested-by: Robert Walker robert.walker@arm.com Signed-off-by: Leo Yan leo.yan@linaro.org Tested-by: Robert Walker robert.walker@arm.com Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Jiri Olsa jolsa@redhat.com Cc: Mathieu Poirier mathieu.poirier@linaro.org Cc: Mike Leach mike.leach@linaro.org Cc: Namhyung Kim namhyung@kernel.org Cc: Suzuki K Poulouse suzuki.poulose@arm.com Cc: linux-arm-kernel@lists.infradead.org Fixes: 7100b12cf474 ("perf cs-etm: Generate branch sample for exception packet") Fixes: 24fff5eb2b93 ("perf cs-etm: Avoid stale branch samples when flush packet") Link: http://lkml.kernel.org/r/20190428083228.20246-1-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/perf/util/cs-etm.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c index 27a374ddf6615..947f1bb2fbdfb 100644 --- a/tools/perf/util/cs-etm.c +++ b/tools/perf/util/cs-etm.c @@ -345,11 +345,9 @@ static struct cs_etm_queue *cs_etm__alloc_queue(struct cs_etm_auxtrace *etm, if (!etmq->packet) goto out_free;
- if (etm->synth_opts.last_branch || etm->sample_branches) { - etmq->prev_packet = zalloc(szp); - if (!etmq->prev_packet) - goto out_free; - } + etmq->prev_packet = zalloc(szp); + if (!etmq->prev_packet) + goto out_free;
if (etm->synth_opts.last_branch) { size_t sz = sizeof(struct branch_stack);