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From: Paolo Bonzini <pbonzini@redhat.com>
To: Gerd Hoffmann <kraxel@redhat.com>, arei.gonglei@huawei.com
Cc: weidong.huang@huawei.com, luonengjun@huawei.com,
	qemu-devel@nongnu.org, lcapitulino@redhat.com, av1474@comtv.ru,
	stefanha@redhat.com
Subject: Re: [Qemu-devel] [PATCH v3 4/4] vga: Fix divide-by-zero in vga_update_text
Date: Thu, 12 Jun 2014 13:07:28 +0200	[thread overview]
Message-ID: <539989F0.9080108@redhat.com> (raw)
In-Reply-To: <1402569830.21444.5.camel@nilsson.home.kraxel.org>

Il 12/06/2014 12:43, Gerd Hoffmann ha scritto:
> That doesn't fix the reported issue.  It's "width" which Coverity thinks
> might be zero, not cursor_offset.  And cursor_offset being zero is
> perfectly fine, happens when the cursor is in the upper left corner.
>
> I have no idea why Coverity thinks width can be zero there.  Line 2047:
>
>         width = (s->cr[VGA_CRTC_H_DISP] + 1);
>
> (where cr is uint8_t).  Hmm, maybe for the wraparound case (i.e.
> s->cr[VGA_CRTC_H_DISP] == 0xff)?

Not even that, the result is 0x100, math is done on the "int" data type.

In fact I don't even see this defect on scan.coverity.com.

Paolo

  reply	other threads:[~2014-06-12 11:08 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-10  9:20 [Qemu-devel] [PATCH v3 0/4] Fix some errors spotted by Coverity arei.gonglei
2014-06-10  9:20 ` [Qemu-devel] [PATCH v3 1/4] json-parser: drop superfluous assignment for token variable arei.gonglei
2014-06-10 12:35   ` Eric Blake
2014-06-10 14:57   ` Luiz Capitulino
2014-06-10  9:20 ` [Qemu-devel] [PATCH v3 2/4] qemu-bridge-helper: Fix fd leak in main() arei.gonglei
2014-06-11 11:31   ` Stefan Hajnoczi
2014-06-10  9:20 ` [Qemu-devel] [PATCH v3 3/4] audio: Fix using freed pointer in wav_fini_out() arei.gonglei
2014-06-10 10:05   ` Peter Maydell
2014-06-12 10:31     ` Gerd Hoffmann
2014-06-12 13:05       ` Gonglei (Arei)
2014-06-12 13:38         ` Gerd Hoffmann
2014-06-10  9:20 ` [Qemu-devel] [PATCH v3 4/4] vga: Fix divide-by-zero in vga_update_text arei.gonglei
2014-06-12 10:43   ` Gerd Hoffmann
2014-06-12 11:07     ` Paolo Bonzini [this message]
2014-06-12 12:58     ` Gonglei (Arei)

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