FAILED: patch "[PATCH] fbcon: Avoid OOB font access if console rotation fails" failed to apply to 6.6-stable tree

FAILED: patch "[PATCH] fbcon: Avoid OOB font access if console rotation fails" failed to apply to 6.6-stable tree

[gregkh]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x e4ef723d8975a2694cc90733a6b888a5e2841842
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026051241-heap-bright-907f@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From e4ef723d8975a2694cc90733a6b888a5e2841842 Mon Sep 17 00:00:00 2001
From: Thomas Zimmermann <tzimmermann@suse.de>
Date: Tue, 7 Apr 2026 11:23:12 +0200
Subject: [PATCH] fbcon: Avoid OOB font access if console rotation fails

Clear the font buffer if the reallocation during console rotation fails
in fbcon_rotate_font(). The putcs implementations for the rotated buffer
will return early in this case. See [1] for an example.

Currently, fbcon_rotate_font() keeps the old buffer, which is too small
for the rotated font. Printing to the rotated console with a high-enough
character code will overflow the font buffer.

v2:
- fix typos in commit message

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 6cc50e1c5b57 ("[PATCH] fbcon: Console Rotation - Add support to rotate font bitmap")
Cc: stable@vger.kernel.org # v2.6.15+
Link: https://elixir.bootlin.com/linux/v6.19/source/drivers/video/fbdev/core/fbcon_ccw.c#L144 # [1]
Signed-off-by: Helge Deller <deller@gmx.de>

diff --git a/drivers/video/fbdev/core/fbcon_rotate.c b/drivers/video/fbdev/core/fbcon_rotate.c
index 1562a8f20b4f..5348f6c6f57c 100644
--- a/drivers/video/fbdev/core/fbcon_rotate.c
+++ b/drivers/video/fbdev/core/fbcon_rotate.c
@@ -46,6 +46,10 @@ int fbcon_rotate_font(struct fb_info *info, struct vc_data *vc)
 		info->fbops->fb_sync(info);
 
 	if (par->fd_size < d_cellsize * len) {
+		kfree(par->fontbuffer);
+		par->fontbuffer = NULL;
+		par->fd_size = 0;
+
 		dst = kmalloc_array(len, d_cellsize, GFP_KERNEL);
 
 		if (dst == NULL) {
@@ -54,7 +58,6 @@ int fbcon_rotate_font(struct fb_info *info, struct vc_data *vc)
 		}
 
 		par->fd_size = d_cellsize * len;
-		kfree(par->fontbuffer);
 		par->fontbuffer = dst;
 	}
 

[PATCH 6.6.y] fbcon: Avoid OOB font access if console rotation fails

[Sasha Levin]

From: Thomas Zimmermann <tzimmermann@suse.de>

[ Upstream commit e4ef723d8975a2694cc90733a6b888a5e2841842 ]

Clear the font buffer if the reallocation during console rotation fails
in fbcon_rotate_font(). The putcs implementations for the rotated buffer
will return early in this case. See [1] for an example.

Currently, fbcon_rotate_font() keeps the old buffer, which is too small
for the rotated font. Printing to the rotated console with a high-enough
character code will overflow the font buffer.

v2:
- fix typos in commit message

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Fixes: 6cc50e1c5b57 ("[PATCH] fbcon: Console Rotation - Add support to rotate font bitmap")
Cc: stable@vger.kernel.org # v2.6.15+
Link: https://elixir.bootlin.com/linux/v6.19/source/drivers/video/fbdev/core/fbcon_ccw.c#L144 # [1]
Signed-off-by: Helge Deller <deller@gmx.de>
[ renamed `par` to `ops` to match the 6.12 local pointer name ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/video/fbdev/core/fbcon_rotate.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/core/fbcon_rotate.c b/drivers/video/fbdev/core/fbcon_rotate.c
index ec3c883400f7b..4a06e71ae4434 100644
--- a/drivers/video/fbdev/core/fbcon_rotate.c
+++ b/drivers/video/fbdev/core/fbcon_rotate.c
@@ -46,6 +46,10 @@ static int fbcon_rotate_font(struct fb_info *info, struct vc_data *vc)
 		info->fbops->fb_sync(info);
 
 	if (ops->fd_size < d_cellsize * len) {
+		kfree(ops->fontbuffer);
+		ops->fontbuffer = NULL;
+		ops->fd_size = 0;
+
 		dst = kmalloc_array(len, d_cellsize, GFP_KERNEL);
 
 		if (dst == NULL) {
@@ -54,7 +58,6 @@ static int fbcon_rotate_font(struct fb_info *info, struct vc_data *vc)
 		}
 
 		ops->fd_size = d_cellsize * len;
-		kfree(ops->fontbuffer);
 		ops->fontbuffer = dst;
 	}
 
-- 
2.53.0