Building with CONFIG_UBSAN_SANITIZE_ALL shows this warning:
drivers/dma/sh/rcar-dmac.c: In function 'rcar_dmac_chan_prep_sg':
drivers/dma/sh/rcar-dmac.c:839:29: error: array subscript is above array bounds [-Werror=array-bounds]
desc->chcr = chcr | chcr_ts[desc->xfer_shift];
As the compiler doesn't know what the xfer_size is, it is impossible
to rule out the array overflow here. As we know that xfer_size
can only be within enum dma_slave_buswidth, this will not overflow
for correct users, and adding a range check will handle the
obscure case and shut up the warning.
Fixes: 87244fe5abdf ("dmaengine: rcar-dmac: Add Renesas R-Car Gen2 DMA Controller (DMAC) driver")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
drivers/dma/sh/rcar-dmac.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index ffcadca53243..f5b28eb4009e 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -836,7 +836,8 @@ static void rcar_dmac_chan_configure_desc(struct rcar_dmac_chan *chan,
}
desc->xfer_shift = ilog2(xfer_size);
- desc->chcr = chcr | chcr_ts[desc->xfer_shift];
+ if (desc->xfer_shift < ARRAY_SIZE(chcr_ts))
+ desc->chcr = chcr | chcr_ts[desc->xfer_shift];
}
/*
--
2.9.0
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