From: Greg Kroah-Hartman Date: Thu, 14 May 2020 11:27:11 +0000 (+0200) Subject: USB: usbfs: fix mmap dma mismatch X-Git-Tag: v5.15~3870^2~3 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=a0e710a7def471b8eb779ff551fc27701da49599;p=platform%2Fkernel%2Flinux-starfive.git USB: usbfs: fix mmap dma mismatch In commit 2bef9aed6f0e ("usb: usbfs: correct kernel->user page attribute mismatch") we switched from always calling remap_pfn_range() to call dma_mmap_coherent() to handle issues with systems with non-coherent USB host controller drivers. Unfortunatly, as syzbot quickly told us, not all the world is host controllers with DMA support, so we need to check what host controller we are attempting to talk to before doing this type of allocation. Thanks to Christoph for the quick idea of how to fix this. Fixes: 2bef9aed6f0e ("usb: usbfs: correct kernel->user page attribute mismatch") Cc: Christoph Hellwig Cc: Hillf Danton Cc: Thomas Gleixner Cc: Jeremy Linton Cc: stable Reported-by: syzbot+353be47c9ce21b68b7ed@syzkaller.appspotmail.com Reviewed-by: Jeremy Linton Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20200514112711.1858252-1-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index b9db981..d93d94d 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -251,9 +251,19 @@ static int usbdev_mmap(struct file *file, struct vm_area_struct *vma) usbm->vma_use_count = 1; INIT_LIST_HEAD(&usbm->memlist); - if (dma_mmap_coherent(hcd->self.sysdev, vma, mem, dma_handle, size)) { - dec_usb_memory_use_count(usbm, &usbm->vma_use_count); - return -EAGAIN; + if (hcd->localmem_pool || !hcd_uses_dma(hcd)) { + if (remap_pfn_range(vma, vma->vm_start, + virt_to_phys(usbm->mem) >> PAGE_SHIFT, + size, vma->vm_page_prot) < 0) { + dec_usb_memory_use_count(usbm, &usbm->vma_use_count); + return -EAGAIN; + } + } else { + if (dma_mmap_coherent(hcd->self.sysdev, vma, mem, dma_handle, + size)) { + dec_usb_memory_use_count(usbm, &usbm->vma_use_count); + return -EAGAIN; + } } vma->vm_flags |= VM_IO;