From: Robin Murphy Date: Tue, 9 Aug 2016 15:23:17 +0000 (+0100) Subject: iommu/dma: Don't put uninitialised IOVA domains X-Git-Tag: firefly_0821_release~176^2~4^2~31^2~253 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=d360081c4bd4361d7df6f879c0f31262ba4f2525;p=firefly-linux-kernel-4.4.55.git iommu/dma: Don't put uninitialised IOVA domains commit 3ec60043f7c02e1f79e4a90045ff2d2e80042941 upstream. Due to the limitations of having to wait until we see a device's DMA restrictions before we know how we want an IOVA domain initialised, there is a window for error if a DMA ops domain is allocated but later freed without ever being used. In that case, init_iova_domain() was never called, so calling put_iova_domain() from iommu_put_dma_cookie() ends up trying to take an uninitialised lock and crashing. Make things robust by skipping the call unless the IOVA domain actually has been initialised, as we probably should have done from the start. Fixes: 0db2e5d18f76 ("iommu: Implement common IOMMU ops for DMA mapping") Reported-by: Nate Watterson Reviewed-by: Nate Watterson Tested-by: Nate Watterson Reviewed-by: Eric Auger Tested-by: Eric Auger Signed-off-by: Robin Murphy Signed-off-by: Joerg Roedel Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 58f2fe687a24..347a3c17f73a 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -68,7 +68,8 @@ void iommu_put_dma_cookie(struct iommu_domain *domain) if (!iovad) return; - put_iova_domain(iovad); + if (iovad->granule) + put_iova_domain(iovad); kfree(iovad); domain->iova_cookie = NULL; }