From: Leo Yan <leo.yan@linaro.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>,
Mathieu Poirier <mathieu.poirier@linaro.org>,
Robert Walker <robert.walker@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Mike Leach <mike.leach@linaro.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Cc: Leo Yan <leo.yan@linaro.org>
Subject: [PATCH v1 1/2] perf cs-etm: Always allocate memory for cs_etm_queue::prev_packet
Date: Sun, 28 Apr 2019 16:32:27 +0800 [thread overview]
Message-ID: <20190428083228.20246-1-leo.yan@linaro.org> (raw)
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>
Fixes: 7100b12cf474 ("perf cs-etm: Generate branch sample for exception packet")
Fixes: 24fff5eb2b93 ("perf cs-etm: Avoid stale branch samples when flush packet")
Signed-off-by: Leo Yan <leo.yan@linaro.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 110804936fc3..054b480aab04 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c
@@ -422,11 +422,9 @@ 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);
--
2.17.1
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next reply other threads:[~2019-04-28 8:32 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-28 8:32 Leo Yan [this message]
2019-04-28 8:32 ` [PATCH v1 2/2] perf cs-etm: Don't check cs_etm_queue::prev_packet validity Leo Yan
2019-04-29 14:53 ` Robert Walker
2019-04-29 14:53 ` [PATCH v1 1/2] perf cs-etm: Always allocate memory for cs_etm_queue::prev_packet Robert Walker
2019-04-30 1:07 ` Arnaldo Carvalho de Melo
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