[PATCH v2] net/i40e: fix unintentional integer overflow

[Yang, SteveX]

> -----Original Message-----
> From: Stephen Hemminger <stephen at networkplumber.org>
> Sent: Thursday, February 24, 2022 12:11 PM
> To: Yang, SteveX <stevex.yang at intel.com>
> Cc: dev at dpdk.org; Yigit, Ferruh <ferruh.yigit at intel.com>; Xing, Beilei
> <beilei.xing at intel.com>; stable at dpdk.org
> Subject: Re: [PATCH v2] net/i40e: fix unintentional integer overflow
> 
> On Thu, 24 Feb 2022 01:17:22 +0000
> Steve Yang <stevex.yang at intel.com> wrote:
> 
> > Cast 1 to type uint64_t to avoid overflow.
> >
> > CID 375812 (#1 of 1):
> > Unintentional integer overflow (OVERFLOW_BEFORE_WIDEN)
> > overflow_before_widen: Potentially overflowing expression 1 << 2 * i +
> > 1 with type int (32 bits, signed) is evaluated using 32-bit
> > arithmetic, and then used in a context that expects an expression of
> > type uint64_t
> > (64 bits, unsigned).
> >
> > Coverity issue: 375812
> > Fixes: 5fec01c35c49 ("net/i40e: support Linux VF to configure IRQ link
> > list")
> > Cc: stable at dpdk.org
> >
> > ---
> > v2: update commit message.
> >
> > Signed-off-by: Steve Yang <stevex.yang at intel.com>
> > ---
> >  drivers/net/i40e/i40e_pf.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/i40e/i40e_pf.c b/drivers/net/i40e/i40e_pf.c
> > index 2435a8a070..39e0c021a4 100644
> > --- a/drivers/net/i40e/i40e_pf.c
> > +++ b/drivers/net/i40e/i40e_pf.c
> > @@ -604,7 +604,7 @@ i40e_pf_config_irq_link_list(struct i40e_pf_vf *vf,
> >  	tempmap = vvm->txq_map;
> >  	for (i = 0; i < sizeof(vvm->txq_map) * BITS_PER_CHAR; i++) {
> >  		if (tempmap & 0x1)
> > -			linklistmap |= (1 << (2 * i + 1));
> > +			linklistmap |= ((uint64_t)1 << (2 * i + 1));
> 
> Could be RTE_BIT64(2 * i + 1) instead?

Thanks Stephen, excellent suggestion.
Current code exist lots of similar nonstandard bit expression,
I think it maybe better to start a new patch series to change them.