From: Thomas Tai <thomas....@oracle.com>
[ Upstream commit f959dcd6ddfd29235030e8026471ac1b022ad2b0 ]
When booting the kernel v5.9-rc4 on a VM, the kernel would panic when
printing a warning message in swiotlb_map(). The dev->dma_mask must not
be a NULL pointer when calling the dma mapping layer. A NULL pointer
check can potentially avoid the panic.
Signed-off-by: Thomas Tai <thomas....@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
Signed-off-by: Christoph Hellwig <h...@lst.de>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
include/linux/dma-direct.h | 3 ---
kernel/dma/mapping.c | 11 +++++++++++
2 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
index 6e87225600ae3..064870844f06c 100644
--- a/include/linux/dma-direct.h
+++ b/include/linux/dma-direct.h
@@ -62,9 +62,6 @@ static inline bool dma_capable(struct device *dev, dma_addr_t
addr, size_t size,
{
dma_addr_t end = addr + size - 1;
- if (!dev->dma_mask)
- return false;
-
if (is_ram && !IS_ENABLED(CONFIG_ARCH_DMA_ADDR_T_64BIT) &&
min(addr, end) < phys_to_dma(dev, PFN_PHYS(min_low_pfn)))
return false;
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 0d129421e75fc..7133d5c6e1a6d 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -144,6 +144,10 @@ dma_addr_t dma_map_page_attrs(struct device *dev, struct
page *page,
dma_addr_t addr;
BUG_ON(!valid_dma_direction(dir));
+
+ if (WARN_ON_ONCE(!dev->dma_mask))
+ return DMA_MAPPING_ERROR;
+
if (dma_map_direct(dev, ops))
addr = dma_direct_map_page(dev, page, offset, size, dir, attrs);
else
@@ -179,6 +183,10 @@ int dma_map_sg_attrs(struct device *dev, struct
scatterlist *sg, int nents,
int ents;
BUG_ON(!valid_dma_direction(dir));
+
+ if (WARN_ON_ONCE(!dev->dma_mask))
+ return 0;
+
if (dma_map_direct(dev, ops))
ents = dma_direct_map_sg(dev, sg, nents, dir, attrs);
else
@@ -213,6 +221,9 @@ dma_addr_t dma_map_resource(struct device *dev, phys_addr_t
phys_addr,
BUG_ON(!valid_dma_direction(dir));
+ if (WARN_ON_ONCE(!dev->dma_mask))
+ return DMA_MAPPING_ERROR;
+
/* Don't allow RAM to be mapped */
if (WARN_ON_ONCE(pfn_valid(PHYS_PFN(phys_addr))))
return DMA_MAPPING_ERROR;
--
2.25.1
