From: Geert Uytterhoeven <geert@linux-m68k.org>
To: George Kennedy <george.kennedy@oracle.com>
Cc: Greg KH <gregkh@linuxfoundation.org>,
Thomas Zimmermann <tzimmermann@suse.de>,
Sam Ravnborg <sam@ravnborg.org>,
DRI Development <dri-devel@lists.freedesktop.org>,
Linux Fbdev development list <linux-fbdev@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] video: fbdev: cirrusfb: check pixclock to avoid divide by zero
Date: Thu, 28 Oct 2021 10:05:00 +0200 [thread overview]
Message-ID: <CAMuHMdXcO1K7da=4Ck2X0Rc_pfaM32dDKf0EfdDXNG0HL18h5Q@mail.gmail.com> (raw)
In-Reply-To: <1635366613-22507-1-git-send-email-george.kennedy@oracle.com>
On Wed, Oct 27, 2021 at 10:32 PM George Kennedy
<george.kennedy@oracle.com> wrote:
> Do a sanity check on pixclock value to avoid divide by zero.
>
> If the pixclock value is zero, the cirrusfb driver will round up
> pixclock to get the derived frequency as close to maxclock as
> possible.
>
> Syzkaller reported a divide error in cirrusfb_check_pixclock.
>
> divide error: 0000 [#1] SMP KASAN PTI
> CPU: 0 PID: 14938 Comm: cirrusfb_test Not tainted 5.15.0-rc6 #1
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2
> RIP: 0010:cirrusfb_check_var+0x6f1/0x1260
>
> Call Trace:
> fb_set_var+0x398/0xf90
> do_fb_ioctl+0x4b8/0x6f0
> fb_ioctl+0xeb/0x130
> __x64_sys_ioctl+0x19d/0x220
> do_syscall_64+0x3a/0x80
> entry_SYSCALL_64_after_hwframe+0x44/0xae
>
> Signed-off-by: George Kennedy <george.kennedy@oracle.com>
Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
next prev parent reply other threads:[~2021-10-28 8:05 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-27 20:30 [PATCH v2] video: fbdev: cirrusfb: check pixclock to avoid divide by zero George Kennedy
2021-10-28 8:05 ` Geert Uytterhoeven [this message]
2021-12-07 19:01 ` George Kennedy
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