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| author | Saeed Mirzamohammadi <saeed.mirzamohammadi@oracle.com> | 2020-10-21 16:57:58 -0700 |
|---|---|---|
| committer | Thomas Zimmermann <tzimmermann@suse.de> | 2020-10-23 08:47:30 +0200 |
| commit | cc07057c7c88fb8eff3b1991131ded0f0bcfa7e3 (patch) | |
| tree | 2db0541c77a0e0d2a1256617ebaf21a49b48b670 /drivers/video | |
| parent | 64a87088b633408a3d58a23f8252846d86df3240 (diff) | |
| download | linux-cc07057c7c88fb8eff3b1991131ded0f0bcfa7e3.tar.bz2 | |
video: fbdev: fix divide error in fbcon_switch
This patch fixes the issue due to:
[ 89.572883] divide_error: 0000 [#1] SMP KASAN PTI
[ 89.572897] CPU: 3 PID: 16083 Comm: repro Not tainted 5.9.0-rc7.20200930.rc1.allarch-19-g3e32d0d.syzk #5
[ 89.572902] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.5.1 01/01/2011
[ 89.572934] RIP: 0010:cirrusfb_check_var+0x84/0x1260
The error happens when the pixels value is calculated before performing the sanity checks on bits_per_pixel.
A bits_per_pixel set to zero causes divide by zero error.
This patch moves the calculation after the sanity check.
Signed-off-by: Saeed Mirzamohammadi <saeed.mirzamohammadi@oracle.com>
Tested-by: Saeed Mirzamohammadi <saeed.mirzamohammadi@oracle.com>
Reviewed-by: Thomas Zimemrmann <tzimmermann@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20201021235758.59993-1-saeed.mirzamohammadi@oracle.com
Diffstat (limited to 'drivers/video')
| -rw-r--r-- | drivers/video/fbdev/cirrusfb.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/video/fbdev/cirrusfb.c b/drivers/video/fbdev/cirrusfb.c index 15a9ee7cd734..e9027172c0f5 100644 --- a/drivers/video/fbdev/cirrusfb.c +++ b/drivers/video/fbdev/cirrusfb.c @@ -531,7 +531,7 @@ static int cirrusfb_check_var(struct fb_var_screeninfo *var, { int yres; /* memory size in pixels */ - unsigned pixels = info->screen_size * 8 / var->bits_per_pixel; + unsigned int pixels; struct cirrusfb_info *cinfo = info->par; switch (var->bits_per_pixel) { @@ -573,6 +573,7 @@ static int cirrusfb_check_var(struct fb_var_screeninfo *var, return -EINVAL; } + pixels = info->screen_size * 8 / var->bits_per_pixel; if (var->xres_virtual < var->xres) var->xres_virtual = var->xres; /* use highest possible virtual resolution */ |