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authorSuzuki K Poulose <suzuki.poulose@arm.com>2019-06-21 20:52:05 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-07-03 22:16:37 +0300
commit17c20f329a139e90e4b049b811ca6d1a2ae967e0 (patch)
tree083d3d84e0b65074d95ec5dda2bc861694ba62b7 /drivers/hwtracing
parent020601622323d02e09cebe05e7976b3d4b44e05d (diff)
downloadlinux-17c20f329a139e90e4b049b811ca6d1a2ae967e0.tar.xz
coresight: tmc: Smatch: Fix potential NULL pointer dereference
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> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> Link: https://lore.kernel.org/r/20190621175205.24551-3-mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/hwtracing')
-rw-r--r--drivers/hwtracing/coresight/coresight-tmc-etr.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 5d2bf6d18961..17006705287a 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);
}