netdev - RE: [Intel-wired-lan] [PATCH iwl-next v2 3/3] igb: allow configuring RSS key via ethtool set

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <IA3PR11MB898612B0CDA9C5A5448733EEE585A@IA3PR11MB8986.namprd11.prod.outlook.com>
Date: Thu, 8 Jan 2026 13:03:12 +0000
From: "Loktionov, Aleksandr" <aleksandr.loktionov@...el.com>
To: "Loktionov, Aleksandr" <aleksandr.loktionov@...el.com>, Kohei Enju
	<enjuk@...zon.com>
CC: "andrew+netdev@...n.ch" <andrew+netdev@...n.ch>, "Nguyen, Anthony L"
	<anthony.l.nguyen@...el.com>, "davem@...emloft.net" <davem@...emloft.net>,
	"edumazet@...gle.com" <edumazet@...gle.com>,
	"intel-wired-lan@...ts.osuosl.org" <intel-wired-lan@...ts.osuosl.org>,
	"kuba@...nel.org" <kuba@...nel.org>, "netdev@...r.kernel.org"
	<netdev@...r.kernel.org>, "pabeni@...hat.com" <pabeni@...hat.com>, "Kitszel,
 Przemyslaw" <przemyslaw.kitszel@...el.com>, "takkozu@...zon.com"
	<takkozu@...zon.com>
Subject: RE: [Intel-wired-lan] [PATCH iwl-next v2 3/3] igb: allow configuring
 RSS key via ethtool set_rxfh



> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@...osl.org> On Behalf
> Of Loktionov, Aleksandr
> Sent: Thursday, January 8, 2026 1:28 PM
> To: Kohei Enju <enjuk@...zon.com>
> Cc: andrew+netdev@...n.ch; Nguyen, Anthony L
> <anthony.l.nguyen@...el.com>; davem@...emloft.net;
> edumazet@...gle.com; intel-wired-lan@...ts.osuosl.org;
> kuba@...nel.org; netdev@...r.kernel.org; pabeni@...hat.com; Kitszel,
> Przemyslaw <przemyslaw.kitszel@...el.com>; takkozu@...zon.com
> Subject: Re: [Intel-wired-lan] [PATCH iwl-next v2 3/3] igb: allow
> configuring RSS key via ethtool set_rxfh
> 
> 
> 
> > -----Original Message-----
> > From: Kohei Enju <enjuk@...zon.com>
> > Sent: Thursday, January 8, 2026 1:04 PM
> > To: Loktionov, Aleksandr <aleksandr.loktionov@...el.com>
> > Cc: andrew+netdev@...n.ch; Nguyen, Anthony L
> > <anthony.l.nguyen@...el.com>; davem@...emloft.net;
> > edumazet@...gle.com; enjuk@...zon.com; intel-wired-
> > lan@...ts.osuosl.org; kuba@...nel.org; netdev@...r.kernel.org;
> > pabeni@...hat.com; Kitszel, Przemyslaw
> <przemyslaw.kitszel@...el.com>;
> > takkozu@...zon.com
> > Subject: Re: RE: [Intel-wired-lan] [PATCH iwl-next v2 3/3] igb:
> allow
> > configuring RSS key via ethtool set_rxfh
> >
> > On Thu, 8 Jan 2026 07:29:19 +0000, Loktionov, Aleksandr wrote:
> >
> > >>
> > >> -	igb_write_rss_indir_tbl(adapter);
> > >> +	if (rxfh->key) {
> > >> +		adapter->has_user_rss_key = true;
> > >> +		memcpy(adapter->rss_key, rxfh->key, sizeof(adapter-
> > >> >rss_key));
> > >> +		igb_write_rss_key(adapter);
> > >It leads to race between ethtool RSS update and concurrent resets.
> > >Because igb_setup_mrqc() (called during resets) also calls
> > igb_write_rss_key(adapter).
> > >Non-fatal but breaks RSS configuration guarantees.
> >
> > At my first glance, rtnl lock serializes those operation, so it
> > doesn't seem to be racy as long as they are under the rtnl lock.
> >
> > As far as I skimmed the codes, functions such as igb_open()/
> > igb_up()/igb_reset_task(), which finally call igb_write_rss_key()
> are
> > serialized by rtnl lock or serializes igb_write_rss_key() call by
> > locking rtnl.
> >
> > Please let me know if I'm missing something and it's truly racy.
> I think you're right, and I've missed that missing rtnl_lock was added
> in upstream.
> 
> Thank you for clarification
> Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@...el.com>
> 

Afterthought, I think it could be nice to place ASSERT_RTNL() to show it explicitly.
What do you think about this idea?