On Wed, Sep 25, 2024 at 04:51:06PM +0300, George Rurikov wrote:
Variable 'scale', whose possible value set allows a zero value in a check at r8169_main.c:2014, is used as a denominator at r8169_main.c:2040 and r8169_main.c:2042.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: 2815b30535a0 ("r8169: merge scale for tx and rx irq coalescing") Cc: stable@vger.kernel.org Signed-off-by: George Rurikov g.ryurikov@securitycode.ru
drivers/net/ethernet/realtek/r8169_main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c index 45ac8befba29..b97e68cfcfad 100644 --- a/drivers/net/ethernet/realtek/r8169_main.c +++ b/drivers/net/ethernet/realtek/r8169_main.c @@ -2011,7 +2011,7 @@ static int rtl_set_coalesce(struct net_device *dev,
coal_usec_max = max(ec->rx_coalesce_usecs, ec->tx_coalesce_usecs); scale = rtl_coalesce_choose_scale(tp, coal_usec_max, &cp01);
if (scale < 0)
if (scale <= 0) return scale;
Please think about this. Say scale is 0, and you return it. It appears the call has worked, but in fact it did nothing.
I much prefer a division by 0, causing a splat, than the silent bug you just added.
Also, please could you explain the code path which results in scale being 0.
Andrew
--- pw-bot: cr