On Mon, Jan 24, 2022 at 10:52:22AM +0100, Helge Deller wrote: > On 1/23/22 23:30, Wei Liu wrote: > > On Sun, Jan 23, 2022 at 10:27:56PM +0000, Michael Kelley (LINUX) wrote: > >> From: Wei Liu <wei.liu@xxxxxxxxxx> Sent: Sunday, January 23, 2022 1:56 PM > >>> > >>> On Sun, Jan 16, 2022 at 09:53:06PM +0000, Haiyang Zhang wrote: > >>>> > >>>> > >>>>> -----Original Message----- > >>>>> From: Michael Kelley (LINUX) <mikelley@xxxxxxxxxxxxx> > >>>>> Sent: Sunday, January 16, 2022 2:19 PM > >>>>> To: KY Srinivasan <kys@xxxxxxxxxxxxx>; Haiyang Zhang > >>> <haiyangz@xxxxxxxxxxxxx>; Stephen > >>>>> Hemminger <sthemmin@xxxxxxxxxxxxx>; wei.liu@xxxxxxxxxx; Wei Hu > >>> <weh@xxxxxxxxxxxxx>; Dexuan > >>>>> Cui <decui@xxxxxxxxxxxxx>; drawat.floss@xxxxxxxxx; hhei <hhei@xxxxxxxxxx>; > >>> linux- > >>>>> kernel@xxxxxxxxxxxxxxx; linux-hyperv@xxxxxxxxxxxxxxx; linux- > >>> fbdev@xxxxxxxxxxxxxxx; dri- > >>>>> devel@xxxxxxxxxxxxxxxxxxxxx > >>>>> Cc: Michael Kelley (LINUX) <mikelley@xxxxxxxxxxxxx> > >>>>> Subject: [PATCH 1/1] video: hyperv_fb: Fix validation of screen resolution > >>>>> > >>>>> In the WIN10 version of the Synthetic Video protocol with Hyper-V, > >>>>> Hyper-V reports a list of supported resolutions as part of the protocol > >>>>> negotiation. The driver calculates the maximum width and height from > >>>>> the list of resolutions, and uses those maximums to validate any screen > >>>>> resolution specified in the video= option on the kernel boot line. > >>>>> > >>>>> This method of validation is incorrect. For example, the list of > >>>>> supported resolutions could contain 1600x1200 and 1920x1080, both of > >>>>> which fit in an 8 Mbyte frame buffer. But calculating the max width > >>>>> and height yields 1920 and 1200, and 1920x1200 resolution does not fit > >>>>> in an 8 Mbyte frame buffer. Unfortunately, this resolution is accepted, > >>>>> causing a kernel fault when the driver accesses memory outside the > >>>>> frame buffer. > >>>>> > >>>>> Instead, validate the specified screen resolution by calculating > >>>>> its size, and comparing against the frame buffer size. Delete the > >>>>> code for calculating the max width and height from the list of > >>>>> resolutions, since these max values have no use. Also add the > >>>>> frame buffer size to the info message to aid in understanding why > >>>>> a resolution might be rejected. > >>>>> > >>>>> Fixes: 67e7cdb4829d ("video: hyperv: hyperv_fb: Obtain screen resolution from Hyper-V > >>>>> host") > >>>>> Signed-off-by: Michael Kelley <mikelley@xxxxxxxxxxxxx> > >>> [...] > >>>> > >>>> Reviewed-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> > >>>> > >>> > >>> Applied to hyperv-fixes. Thanks. > >> > >> This fix got pulled into the fbdev/for-next tree by a new maintainer, Helge Deller. > >> See https://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev.git/commit/?h=for-next&id=bcc48f8d980b12e66a3d59dfa1041667db971d86 > > > > OK. I will drop it from hyperv-fixes. Thanks for letting me know! > > Linus hasn't pulled my tree yet, and he will probably not before the > next merge window. So, if this is an urgent bugfix for you, I can offer > to drop it from the fbdev tree and that you take it through the hyperv-fixes tree. > In that case you may add an Acked-by: Helge Deller <deller@xxxxxx>. > Just let me know what you prefer. Hi Helge Yes, I would like to upstream it as soon as possible so that it can propagate to stable trees and be backported by downstream vendors. I will pick it up in hyperv-fixes. Please drop it from your for-next tree. Thanks, Wei. > > Helge