From: Suzuki K Poulose <suzuki.poulose@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: coresight@lists.linaro.org,
Dan Carpenter <dan.carpenter@oracle.com>,
mathieu.poirier@linaro.org,
Suzuki K Poulose <suzuki.poulose@arm.com>
Subject: [PATCH 2/2] coresight: tmc: Smatch: Fix potential NULL pointer dereference
Date: Thu, 13 Jun 2019 11:06:26 +0100 [thread overview]
Message-ID: <1560420386-4239-2-git-send-email-suzuki.poulose@arm.com> (raw)
In-Reply-To: <1560420386-4239-1-git-send-email-suzuki.poulose@arm.com>
Based on the following report from Smatch, fix the potential
NULL pointer dereference check.
The patch 743256e214e8: "coresight: tmc: Clean up device specific
data" from May 22, 2019, leads to the following Smatch complaint:
drivers/hwtracing/coresight/coresight-tmc-etr.c:625 tmc_etr_free_flat_buf()
warn: variable dereferenced before check 'flat_buf' (see line 623)
drivers/hwtracing/coresight/coresight-tmc-etr.c
622 struct etr_flat_buf *flat_buf = etr_buf->private;
623 struct device *real_dev = flat_buf->dev->parent;
^^^^^^^^^^
The patch introduces a new NULL check
624
625 if (flat_buf && flat_buf->daddr)
^^^^^^^^
but the existing code assumed it can be NULL.
626 dma_free_coherent(real_dev, flat_buf->size,
627 flat_buf->vaddr, flat_buf->daddr);
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
drivers/hwtracing/coresight/coresight-tmc-etr.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 5d2bf6d..1700670 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -620,11 +620,13 @@ static int tmc_etr_alloc_flat_buf(struct tmc_drvdata *drvdata,
static void tmc_etr_free_flat_buf(struct etr_buf *etr_buf)
{
struct etr_flat_buf *flat_buf = etr_buf->private;
- struct device *real_dev = flat_buf->dev->parent;
- if (flat_buf && flat_buf->daddr)
+ if (flat_buf && flat_buf->daddr) {
+ struct device *real_dev = flat_buf->dev->parent;
+
dma_free_coherent(real_dev, flat_buf->size,
flat_buf->vaddr, flat_buf->daddr);
+ }
kfree(flat_buf);
}
--
2.7.4
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next prev parent reply other threads:[~2019-06-13 10:06 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-13 10:06 [PATCH 1/2] coresight: etm3x: Smatch: Fix potential NULL pointer dereference Suzuki K Poulose
2019-06-13 10:06 ` Suzuki K Poulose [this message]
2019-06-17 19:28 ` Mathieu Poirier
2019-06-21 17:52 [PATCH 0/2] coresight: next v5.2-rc5 (Part 2) Mathieu Poirier
2019-06-21 17:52 ` [PATCH 2/2] coresight: tmc: Smatch: Fix potential NULL pointer dereference Mathieu Poirier
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