From 298a96c12b2d8fd845ae0c2c21c0a1c0b470f99e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Sun, 25 Oct 2015 23:11:43 +0200 Subject: [PATCH] x86/dma-mapping: Fix arch_dma_alloc_attrs() oops with NULL dev MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Commit 6894258eda2f broke drivers that pass NULL as the device pointer to dma_alloc. The reason is that arch_dma_alloc_attrs() now calls dma_alloc_coherent_gfp_flags() which in turn calls dma_alloc_coherent_mask(), where the device pointer is dereferenced unconditionally. Fix things by moving the ISA DMA fallback device assignment before the call to dma_alloc_coherent_gfp_flags(). Fixes: 6894258eda2f ("dma-mapping: consolidate dma_{alloc,free}_{attrs,coherent}") Reported-and-tested-by: Meelis Roos Signed-off-by: Ville Syrjälä Cc: Christoph Hellwig Link: http://lkml.kernel.org/r/1445807503-8920-1-git-send-email-ville.syrjala@linux.intel.com Signed-off-by: Thomas Gleixner --- arch/x86/kernel/pci-dma.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c index 1b55de1267cf..cd99433b8ba1 100644 --- a/arch/x86/kernel/pci-dma.c +++ b/arch/x86/kernel/pci-dma.c @@ -131,11 +131,12 @@ void dma_generic_free_coherent(struct device *dev, size_t size, void *vaddr, bool arch_dma_alloc_attrs(struct device **dev, gfp_t *gfp) { + if (!*dev) + *dev = &x86_dma_fallback_dev; + *gfp &= ~(__GFP_DMA | __GFP_HIGHMEM | __GFP_DMA32); *gfp = dma_alloc_coherent_gfp_flags(*dev, *gfp); - if (!*dev) - *dev = &x86_dma_fallback_dev; if (!is_device_dma_capable(*dev)) return false; return true;