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authorLukas Wunner <lukas@wunner.de>2019-12-05 12:54:49 +0100
committerVinod Koul <vkoul@kernel.org>2019-12-11 11:33:20 +0100
commit53a256a9b925b47c7e67fc1f16ca41561a7b877c (patch)
treee822373218a9827e99f46e6d7a9014c670896ef8 /include
parentLinux 5.5-rc1 (diff)
downloadlinux-53a256a9b925b47c7e67fc1f16ca41561a7b877c.tar.xz
linux-53a256a9b925b47c7e67fc1f16ca41561a7b877c.zip
dmaengine: Fix access to uninitialized dma_slave_caps
dmaengine_desc_set_reuse() allocates a struct dma_slave_caps on the stack, populates it using dma_get_slave_caps() and then accesses one of its members. However dma_get_slave_caps() may fail and this isn't accounted for, leading to a legitimate warning of gcc-4.9 (but not newer versions): In file included from drivers/spi/spi-bcm2835.c:19:0: drivers/spi/spi-bcm2835.c: In function 'dmaengine_desc_set_reuse': >> include/linux/dmaengine.h:1370:10: warning: 'caps.descriptor_reuse' is used uninitialized in this function [-Wuninitialized] if (caps.descriptor_reuse) { Fix it, thereby also silencing the gcc-4.9 warning. The issue has been present for 4 years but surfaces only now that the first caller of dmaengine_desc_set_reuse() has been added in spi-bcm2835.c. Another user of reusable DMA descriptors has existed for a while in pxa_camera.c, but it sets the DMA_CTRL_REUSE flag directly instead of calling dmaengine_desc_set_reuse(). Nevertheless, tag this commit for stable in case there are out-of-tree users. Fixes: 272420214d26 ("dmaengine: Add DMA_CTRL_REUSE") Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Lukas Wunner <lukas@wunner.de> Cc: stable@vger.kernel.org # v4.3+ Link: https://lore.kernel.org/r/ca92998ccc054b4f2bfd60ef3adbab2913171eac.1575546234.git.lukas@wunner.de Signed-off-by: Vinod Koul <vkoul@kernel.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/dmaengine.h5
1 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 8fcdee1c0cf9..dad4a68fa009 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -1364,8 +1364,11 @@ static inline int dma_get_slave_caps(struct dma_chan *chan,
static inline int dmaengine_desc_set_reuse(struct dma_async_tx_descriptor *tx)
{
struct dma_slave_caps caps;
+ int ret;
- dma_get_slave_caps(tx->chan, &caps);
+ ret = dma_get_slave_caps(tx->chan, &caps);
+ if (ret)
+ return ret;
if (caps.descriptor_reuse) {
tx->flags |= DMA_CTRL_REUSE;