From: David Marchand <david.marchand@redhat.com>
To: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
Luc Pelletier <lucp.at.work@gmail.com>
Cc: "Richardson, Bruce" <bruce.richardson@intel.com>,
"dev@dpdk.org" <dev@dpdk.org>,
"Li, Xiaoyun" <xiaoyun.li@intel.com>,
"stable@dpdk.org" <stable@dpdk.org>,
Aaron Conole <aconole@redhat.com>,
Owen Hilyard <ohilyard@iol.unh.edu>
Subject: Re: [PATCH v7] eal: fix rte_memcpy strict aliasing/alignment bugs
Date: Thu, 7 Apr 2022 17:24:07 +0200 [thread overview]
Message-ID: <CAJFAV8yxK-qqQtNLrNFqyo1T+6qTSGfotSGufgR1SOY1muMzdg@mail.gmail.com> (raw)
In-Reply-To: <DM6PR11MB449118A6002204BEA83D1B7A9A0B9@DM6PR11MB4491.namprd11.prod.outlook.com>
On Thu, Mar 10, 2022 at 3:55 PM Ananyev, Konstantin
<konstantin.ananyev@intel.com> wrote:
> > Calls to rte_memcpy for 1 < n < 16 could result in unaligned
> > loads/stores, which is undefined behaviour according to the C
> > standard, and strict aliasing violations.
> >
> > The code was changed to use a packed structure that allows aliasing
> > (using the __may_alias__ attribute) to perform the load/store
> > operations. This results in code that has the same performance as the
> > original code and that is also C standards-compliant.
> >
> > Fixes: d35cc1fe6a7a ("eal/x86: revert select optimized memcpy at run-time")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Luc Pelletier <lucp.at.work@gmail.com>
> Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
> Tested-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
Thanks, applied.
> As a side note, we probably need to check other similar places in DPDK code.
What would be the best way to detect those problematic places?
I tried UBsan, and it did report some of the issues fixed with this patch.
--
David Marchand
next prev parent reply other threads:[~2022-04-07 15:24 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-15 19:41 [PATCH] eal: fix unaligned loads/stores in rte_memcpy_generic Luc Pelletier
2022-01-15 21:39 ` [PATCH v2] " Luc Pelletier
2022-01-15 22:13 ` Stephen Hemminger
2022-01-16 14:09 ` Luc Pelletier
2022-01-16 16:32 ` Stephen Hemminger
2022-01-16 14:13 ` [PATCH v3] " Luc Pelletier
2022-01-16 14:33 ` Luc Pelletier
2022-01-16 16:34 ` Stephen Hemminger
2022-01-16 17:59 ` Morten Brørup
2022-01-16 20:33 ` [PATCH v4] " Luc Pelletier
2022-01-17 15:37 ` [PATCH v5] " Luc Pelletier
2022-02-04 16:42 ` Luc Pelletier
2022-02-04 17:16 ` Ananyev, Konstantin
2022-02-08 16:53 ` Thomas Monjalon
2022-02-09 15:05 ` Luc Pelletier
2022-02-10 14:04 ` Ananyev, Konstantin
2022-02-10 16:56 ` Luc Pelletier
2022-02-11 15:51 ` Ananyev, Konstantin
2022-02-13 22:31 ` Luc Pelletier
2022-02-14 13:41 ` Ananyev, Konstantin
2022-02-25 15:51 ` [PATCH v6] eal: fix rte_memcpy strict aliasing/alignment bugs Luc Pelletier
2022-02-25 16:38 ` [PATCH v7] " Luc Pelletier
2022-03-10 14:55 ` Ananyev, Konstantin
2022-04-07 15:24 ` David Marchand [this message]
2022-04-07 15:32 ` David Marchand
2022-04-07 15:40 ` David Marchand
2022-05-13 19:15 ` Luc Pelletier
2022-05-19 16:41 ` David Marchand
2022-04-08 13:47 ` Luc Pelletier
2022-05-19 16:47 ` David Marchand
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