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Message-ID: <20240705190929.GC1480790@kernel.org>
Date: Fri, 5 Jul 2024 20:09:29 +0100
From: Simon Horman <horms@...nel.org>
To: Michael Chan <michael.chan@...adcom.com>
Cc: "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>,
netdev@...r.kernel.org
Subject: Re: [PATCH net-next 2/3] bnxt_en: check for irq name truncation
On Fri, Jul 05, 2024 at 11:27:47AM -0700, Michael Chan wrote:
> On Fri, Jul 5, 2024 at 4:27 AM Simon Horman <horms@...nel.org> wrote:
> > diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> > index 220d05e2f6fa..15e68c8e599d 100644
> > --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> > +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> > @@ -10538,7 +10538,7 @@ static int bnxt_trim_rings(struct bnxt *bp, int *rx, int *tx, int max,
> > return __bnxt_trim_rings(bp, rx, tx, max, sh);
> > }
> >
> > -static void bnxt_setup_msix(struct bnxt *bp)
> > +static int bnxt_setup_msix(struct bnxt *bp)
> > {
> > const int len = sizeof(bp->irq_tbl[0].name);
> > struct net_device *dev = bp->dev;
> > @@ -10558,6 +10558,7 @@ static void bnxt_setup_msix(struct bnxt *bp)
> > for (i = 0; i < bp->cp_nr_rings; i++) {
> > int map_idx = bnxt_cp_num_to_irq_num(bp, i);
> > char *attr;
> > + int rc;
> >
> > if (bp->flags & BNXT_FLAG_SHARED_RINGS)
> > attr = "TxRx";
> > @@ -10566,24 +10567,35 @@ static void bnxt_setup_msix(struct bnxt *bp)
> > else
> > attr = "tx";
> >
> > - snprintf(bp->irq_tbl[map_idx].name, len, "%s-%s-%d", dev->name,
> > - attr, i);
> > + rc = snprintf(bp->irq_tbl[map_idx].name, len, "%s-%s-%d",
> > + dev->name, attr, i);
> > + if (rc >= len)
> > + return -E2BIG;
>
> I may be missing something obvious here. snprintf() will truncate and
> not overwrite the buffer, right? Why is it necessary to abort if
> there is truncation? Thanks.
The (incorrect) assumption on my side was that truncated names
are undesirable and should be treated as an error case.
Sorry for not making that clearer.
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