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| 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 /kernel/dma/mapping.c | |
| parent | a92df4f62fda02e6b141e2b0bb52ccc486264b1c (diff) | |
| download | linux-f959dcd6ddfd29235030e8026471ac1b022ad2b0.tar.gz linux-f959dcd6ddfd29235030e8026471ac1b022ad2b0.tar.bz2 linux-f959dcd6ddfd29235030e8026471ac1b022ad2b0.zip | |
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>
Diffstat (limited to 'kernel/dma/mapping.c')
| -rw-r--r-- | kernel/dma/mapping.c | 11 |
1 files changed, 11 insertions, 0 deletions
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; |