On Mon, Jul 26, 2010 at 03:38:12PM -0700, Andrew Morton wrote: > On Thu, 22 Jul 2010 17:31:28 -0400 > Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> wrote: > > > This bug was found when Linux kernel was running under Xen. > > In that scenario, any page that has VM_IO flag to it, means that it > > MUST be a MMIO/VRAM backend memory , _not_ System RAM. That is what the > > fbmem.c does: sets VM_IO, ioremaps the region - everything is peachy. > > > > Well, not exactly. The vm_page_prot does not get the relevant > > PTE flags set (_PAGE_IOMAP) which under Xen is a death-kneel to pages > > that are referencing real physical devices but don't have that flag set. > > > > Here is the patch: > > > > Author: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx> > > Date: Wed Jul 21 16:52:46 2010 -0400 > > > > fb: propagate VM_IO to VMA. > > > > When we setup up the VMA flags for the mmap flag and we end up using > > the fallback mmap functionality we set the vma->vm_flags |= VM_IO. > > However we neglect to propagate the flag to the vma->vm_page_prot. > > > > This patch fixes this. > > > > Tested-by: Eamon Walsh <ewalsh@xxxxxxxxxxxxx> > > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> > > > > Confused. We have From:Konrad and Author:Daniel and no signoff from Daniel. So Daniel came up with the original fix, I've came to him and suggested that perhaps we should use the vm_get_page_prot, and he agreed. Since I've kept the patch in my branch of "Xen-KMS/DRM/TTM-fixes" I figured I should post the patch upstream and hence I signed off on it. > > I've committed the patch assuming that Daniel was the author, but > didn't sign off the patch. Your signoff is sufficient for merging Yes. He is the author. Let me refer back to my notes but I figured if the patch has an Author: set there was no need for an extra S-o-b? > purposes. > > But maybe I was wrong. > > > I'm also assuming that we can merge this into 2.6.36 and not backport > it into -stable. But maybe I'm wrong about that too! Talk to me. No need to backport it. -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
