This is a note to let you know that I've just added the patch titled
video: fbdev: riva: Error out if 'pixclock' equals zero
to the 4.19-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:
video-fbdev-riva-error-out-if-pixclock-equals-zero.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 8eb852ef9775caca4ea5a8d5174bf344729091cc
Author: Zheyu Ma <zheyuma97@xxxxxxxxx>
Date: Mon Jul 26 10:03:55 2021 +0000
video: fbdev: riva: Error out if 'pixclock' equals zero
[ Upstream commit f92763cb0feba247e0939ed137b495601fd072a5 ]
The userspace program could pass any values to the driver through
ioctl() interface. If the driver doesn't check the value of 'pixclock',
it may cause divide error.
Fix this by checking whether 'pixclock' is zero first.
The following log reveals it:
[ 33.396850] divide error: 0000 [#1] PREEMPT SMP KASAN PTI
[ 33.396864] CPU: 5 PID: 11754 Comm: i740 Not tainted 5.14.0-rc2-00513-gac532c9bbcfb-dirty #222
[ 33.396883] RIP: 0010:riva_load_video_mode+0x417/0xf70
[ 33.396969] Call Trace:
[ 33.396973] ? debug_smp_processor_id+0x1c/0x20
[ 33.396984] ? tick_nohz_tick_stopped+0x1a/0x90
[ 33.396996] ? rivafb_copyarea+0x3c0/0x3c0
[ 33.397003] ? wake_up_klogd.part.0+0x99/0xd0
[ 33.397014] ? vprintk_emit+0x110/0x4b0
[ 33.397024] ? vprintk_default+0x26/0x30
[ 33.397033] ? vprintk+0x9c/0x1f0
[ 33.397041] ? printk+0xba/0xed
[ 33.397054] ? record_print_text.cold+0x16/0x16
[ 33.397063] ? __kasan_check_read+0x11/0x20
[ 33.397074] ? profile_tick+0xc0/0x100
[ 33.397084] ? __sanitizer_cov_trace_const_cmp4+0x24/0x80
[ 33.397094] ? riva_set_rop_solid+0x2a0/0x2a0
[ 33.397102] rivafb_set_par+0xbe/0x610
[ 33.397111] ? riva_set_rop_solid+0x2a0/0x2a0
[ 33.397119] fb_set_var+0x5bf/0xeb0
[ 33.397127] ? fb_blank+0x1a0/0x1a0
[ 33.397134] ? lock_acquire+0x1ef/0x530
[ 33.397143] ? lock_release+0x810/0x810
[ 33.397151] ? lock_is_held_type+0x100/0x140
[ 33.397159] ? ___might_sleep+0x1ee/0x2d0
[ 33.397170] ? __mutex_lock+0x620/0x1190
[ 33.397180] ? trace_hardirqs_on+0x6a/0x1c0
[ 33.397190] do_fb_ioctl+0x31e/0x700
Signed-off-by: Zheyu Ma <zheyuma97@xxxxxxxxx>
Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/1627293835-17441-4-git-send-email-zheyuma97@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/video/fbdev/riva/fbdev.c b/drivers/video/fbdev/riva/fbdev.c
index cc242ba057d3..dfa81b641f9f 100644
--- a/drivers/video/fbdev/riva/fbdev.c
+++ b/drivers/video/fbdev/riva/fbdev.c
@@ -1088,6 +1088,9 @@ static int rivafb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
int mode_valid = 0;
NVTRACE_ENTER();
+ if (!var->pixclock)
+ return -EINVAL;
+
switch (var->bits_per_pixel) {
case 1 ... 8:
var->red.offset = var->green.offset = var->blue.offset = 0;
