diff options
| author | Thomas Tai <thomas.tai@oracle.com> | 2020-09-17 18:43:03 +0200 |
|---|---|---|
| committer | Christoph Hellwig <hch@lst.de> | 2020-09-17 18:43:20 +0200 |
| commit | f959dcd6ddfd29235030e8026471ac1b022ad2b0 (patch) | |
| tree | b3bb71e9171c97f693240bdeb3e9ad2f0a5d580c | |
| parent | a92df4f62fda02e6b141e2b0bb52ccc486264b1c (diff) | |
dma-direct: Fix potential NULL pointer dereference
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.tai@oracle.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
| -rw-r--r-- | include/linux/dma-direct.h | 3 | ||||
| -rw-r--r-- | 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 805010ea5346..2929685e88aa 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 848c95c27d79..9a045e51df17 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; |