From: "Morten Brørup" <mb@smartsharesystems.com>
To: "Stephen Hemminger" <stephen@networkplumber.org>
Cc: "Megha Ajmera" <megha.ajmera@intel.com>, <dev@dpdk.org>,
<sham.singh.thakur@intel.com>, <john.mcnamara@intel.com>
Subject: RE: [PATCH] sched: fix integer handling issue
Date: Wed, 23 Feb 2022 08:17:49 +0100 [thread overview]
Message-ID: <98CBD80474FA8B44BF855DF32C47DC35D86EDE@smartserver.smartshare.dk> (raw)
In-Reply-To: <20220222080306.1caf1fc9@hermes.local>
> From: Stephen Hemminger [mailto:stephen@networkplumber.org]
> Sent: Tuesday, 22 February 2022 17.03
>
> On Tue, 22 Feb 2022 15:13:53 +0100
> Morten Brørup <mb@smartsharesystems.com> wrote:
>
> > > From: Megha Ajmera [mailto:megha.ajmera@intel.com]
> > > Sent: Tuesday, 22 February 2022 14.19
> > >
> > > Masking of core mask was incorrect. Instead of using 1U for
> shifting,
> > > it
> > > should be using 1LU as the result is assigned to uint64.
> > >
> > > CID 375859: Potentially overflowing expression "1U <<
> app_main_core"
> > > with
> > > type "unsigned int" (32 bits, unsigned) 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: 375859
> > >
> > > Signed-off-by: Megha Ajmera <megha.ajmera@intel.com>
> > > ---
> > > examples/qos_sched/args.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/examples/qos_sched/args.c b/examples/qos_sched/args.c
> > > index 10ca7bea61..44f2f5640e 100644
> > > --- a/examples/qos_sched/args.c
> > > +++ b/examples/qos_sched/args.c
> > > @@ -433,7 +433,7 @@ app_parse_args(int argc, char **argv)
> > > return -1;
> > > }
> > > }
> > > - app_used_core_mask |= 1u << app_main_core;
> > > + app_used_core_mask |= 1lu << app_main_core;
> >
> > Still wrong on 32 bit platforms, where long unsigned int is still 32
> bits.
> >
> > Use this instead:
> > app_used_core_mask |= RTE_BIT64(app_main_core);
>
> DPDK now supports > 64 lcores. So all code using/assuming a 64 bit mask
> is broken.
>
Good point. Is there a TODO-list where such a general review request can be filed, or should we just file it as a system-wide bug in Bugzilla?
Nonetheless, I think this one-line fix should be accepted as a short term solution.
-Morten
next prev parent reply other threads:[~2022-02-23 7:17 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-22 13:18 [PATCH] sched: fix integer handling issue Megha Ajmera
2022-02-22 14:13 ` Morten Brørup
2022-02-22 16:03 ` Stephen Hemminger
2022-02-22 18:55 ` Ajmera, Megha
2022-02-23 7:17 ` Morten Brørup [this message]
2022-02-23 10:03 ` Ferruh Yigit
2022-02-23 10:42 ` more than 64 lcores not properly supported Morten Brørup
2022-02-23 11:20 ` Ferruh Yigit
2022-02-23 13:49 ` Thomas Monjalon
2022-02-23 15:12 ` Stephen Hemminger
2022-02-23 17:36 ` [PATCH v2] sched: fix integer handling issue Megha Ajmera
2022-02-23 18:13 ` Morten Brørup
2022-02-24 22:51 ` Thomas Monjalon
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