This is a note to let you know that I've just added the patch titled
drm/modes: Switch to 64bit maths to avoid integer overflow
to the 5.11-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-modes-switch-to-64bit-maths-to-avoid-integer-overflow.patch
and it can be found in the queue-5.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 5b34ab52401f0f1f191bcb83a182c83b506f4763 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <ville.syrjala@xxxxxxxxxxxxxxx>
Date: Thu, 22 Oct 2020 22:42:56 +0300
Subject: drm/modes: Switch to 64bit maths to avoid integer overflow
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From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
commit 5b34ab52401f0f1f191bcb83a182c83b506f4763 upstream.
The new >8k CEA modes have dotclocks reaching 5.94 GHz, which
means our clock*1000 will now overflow the 32bit unsigned
integer. Switch to 64bit maths to avoid it.
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20201022194256.30978-1-ville.syrjala@xxxxxxxxxxxxxxx
Tested-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_modes.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/drm_modes.c
+++ b/drivers/gpu/drm/drm_modes.c
@@ -762,7 +762,7 @@ int drm_mode_vrefresh(const struct drm_d
if (mode->htotal == 0 || mode->vtotal == 0)
return 0;
- num = mode->clock * 1000;
+ num = mode->clock;
den = mode->htotal * mode->vtotal;
if (mode->flags & DRM_MODE_FLAG_INTERLACE)
@@ -772,7 +772,7 @@ int drm_mode_vrefresh(const struct drm_d
if (mode->vscan > 1)
den *= mode->vscan;
- return DIV_ROUND_CLOSEST(num, den);
+ return DIV_ROUND_CLOSEST_ULL(mul_u32_u32(num, 1000), den);
}
EXPORT_SYMBOL(drm_mode_vrefresh);
Patches currently in stable-queue which might be from ville.syrjala@xxxxxxxxxxxxxxx are
queue-5.11/drm-modes-switch-to-64bit-maths-to-avoid-integer-overflow.patch
queue-5.11/drm-document-that-user-space-should-force-probe-conn.patch
