Patch "drm/nouveau/fbcon: fix font width not divisible by 8" has been added to the 4.4-stable tree

Patch "drm/nouveau/fbcon: fix font width not divisible by 8" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    drm/nouveau/fbcon: fix font width not divisible by 8

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-nouveau-fbcon-fix-font-width-not-divisible-by-8.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 28668f43b8e421634e1623f72a879812288dd06b Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka@redhat.com>
Date: Thu, 28 Jul 2016 18:56:13 -0400
Subject: drm/nouveau/fbcon: fix font width not divisible by 8

From: Mikulas Patocka <mpatocka@redhat.com>

commit 28668f43b8e421634e1623f72a879812288dd06b upstream.

The patch f045f459d925 ("drm/nouveau/fbcon: fix out-of-bounds memory accesses")
tries to fix some out of memory accesses. Unfortunatelly, the patch breaks the
display when using fonts with width that is not divisiable by 8.

The monochrome bitmap for each character is stored in memory by lines from top
to bottom. Each line is padded to a full byte.

For example, for 22x11 font, each line is padded to 16 bits, so each
character is consuming 44 bytes total, that is 11 32-bit words. The patch
f045f459d925 changed the logic to "dsize = ALIGN(image->width *
image->height, 32) >> 5", that is just 8 words - this is incorrect and it
causes display corruption.

This patch adds the necesary padding of lines to 8 bytes.

This patch should be backported to stable kernels where f045f459d925 was
backported.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Fixes: f045f459d925 ("drm/nouveau/fbcon: fix out-of-bounds memory accesses")
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/gpu/drm/nouveau/nv04_fbcon.c |    4 ++--
 drivers/gpu/drm/nouveau/nv50_fbcon.c |    2 +-
 drivers/gpu/drm/nouveau/nvc0_fbcon.c |    2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/gpu/drm/nouveau/nv04_fbcon.c
+++ b/drivers/gpu/drm/nouveau/nv04_fbcon.c
@@ -107,11 +107,11 @@ nv04_fbcon_imageblit(struct fb_info *inf
 			 ((image->dx + image->width) & 0xffff));
 	OUT_RING(chan, bg);
 	OUT_RING(chan, fg);
-	OUT_RING(chan, (image->height << 16) | image->width);
+	OUT_RING(chan, (image->height << 16) | ALIGN(image->width, 8));
 	OUT_RING(chan, (image->height << 16) | image->width);
 	OUT_RING(chan, (image->dy << 16) | (image->dx & 0xffff));
 
-	dsize = ALIGN(image->width * image->height, 32) >> 5;
+	dsize = ALIGN(ALIGN(image->width, 8) * image->height, 32) >> 5;
 	while (dsize) {
 		int iter_len = dsize > 128 ? 128 : dsize;
 
--- a/drivers/gpu/drm/nouveau/nv50_fbcon.c
+++ b/drivers/gpu/drm/nouveau/nv50_fbcon.c
@@ -125,7 +125,7 @@ nv50_fbcon_imageblit(struct fb_info *inf
 	OUT_RING(chan, 0);
 	OUT_RING(chan, image->dy);
 
-	dwords = ALIGN(image->width * image->height, 32) >> 5;
+	dwords = ALIGN(ALIGN(image->width, 8) * image->height, 32) >> 5;
 	while (dwords) {
 		int push = dwords > 2047 ? 2047 : dwords;
 
--- a/drivers/gpu/drm/nouveau/nvc0_fbcon.c
+++ b/drivers/gpu/drm/nouveau/nvc0_fbcon.c
@@ -125,7 +125,7 @@ nvc0_fbcon_imageblit(struct fb_info *inf
 	OUT_RING  (chan, 0);
 	OUT_RING  (chan, image->dy);
 
-	dwords = ALIGN(image->width * image->height, 32) >> 5;
+	dwords = ALIGN(ALIGN(image->width, 8) * image->height, 32) >> 5;
 	while (dwords) {
 		int push = dwords > 2047 ? 2047 : dwords;
 


Patches currently in stable-queue which might be from mpatocka@redhat.com are

queue-4.4/drm-nouveau-fbcon-fix-font-width-not-divisible-by-8.patch