Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Thu, 11 Jan 2024 10:00:53 +0100 | Subject | Re: [PATCH] dmaengine: sh: rz-dmac: Avoid format-overflow warning |
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Hi Prabhakar,
On Wed, Jan 10, 2024 at 11:27 PM Prabhakar <prabhakar.csengg@gmail.com> wrote: > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> > > The max channel count for RZ DMAC is 16, hence use u8 instead of unsigned > int and make the pdev_irqname string long enough to avoid the warning.
Note that the danger lies into someone changing RZ_DMAC_MAX_CHANNELS later...
> This fixes the below issue: > drivers/dma/sh/rz-dmac.c: In function ‘rz_dmac_probe’: > drivers/dma/sh/rz-dmac.c:770:34: warning: ‘%u’ directive writing between 1 and 10 bytes into a region of size 3 [-Wformat-overflow=] > 770 | sprintf(pdev_irqname, "ch%u", index); > | ^~ > In function ‘rz_dmac_chan_probe’, > inlined from ‘rz_dmac_probe’ at drivers/dma/sh/rz-dmac.c:910:9: > drivers/dma/sh/rz-dmac.c:770:31: note: directive argument in the range [0, 4294967294] > 770 | sprintf(pdev_irqname, "ch%u", index); > | ^~~~~~ > drivers/dma/sh/rz-dmac.c:770:9: note: ‘sprintf’ output between 4 and 13 bytes into a destination of size 5 > 770 | sprintf(pdev_irqname, "ch%u", index); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > While at it use scnprintf() instead of sprintf() to make the code > more robust. > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Some nits below...
> --- a/drivers/dma/sh/rz-dmac.c > +++ b/drivers/dma/sh/rz-dmac.c > @@ -845,9 +845,9 @@ static int rz_dmac_probe(struct platform_device *pdev) > struct dma_device *engine; > struct rz_dmac *dmac; > int channel_num; > - unsigned int i; > int ret; > int irq; > + u8 i;
Personally, I'm not much a fan of making loop counters smaller than (unsigned) int. If you do go this way, you should change channel_num to u8, too, just like i in rz_dmac_remove().
> > dmac = devm_kzalloc(&pdev->dev, sizeof(*dmac), GFP_KERNEL); > if (!dmac)
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68korg
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
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