Date: Fri, 29 Dec 2023 21:13:18 +0100
From: Salvatore Bonaccorso <carnil@...ian.org>
To: Thorsten Leemhuis <regressions@...mhuis.info>
Cc: Greg KH <gregkh@...uxfoundation.org>,
	Sagar Biradar <sagar.biradar@...rochip.com>,
	James Bottomley <James.Bottomley@...senpartnership.com>,
	"Martin K. Petersen" <martin.petersen@...cle.com>,
	Adaptec OEM Raid Solutions <aacraid@...rosemi.com>,
	"stable@...r.kernel.org" <stable@...r.kernel.org>,
	Sasha Levin <sashal@...nel.org>,
	Linux kernel regressions list <regressions@...ts.linux.dev>,
	Hannes Reinecke <hare@...e.de>, scsi <linux-scsi@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Gilbert Wu <gilbert.wu@...rochip.com>,
	John Garry <john.g.garry@...cle.com>
Subject: Re: scsi regression that after months is still not addressed and now
 bothering 6.1.y users, too

Hi all,

On Sat, Nov 25, 2023 at 08:10:35AM +0100, Thorsten Leemhuis wrote:
> On 24.11.23 17:25, Greg KH wrote:
> > On Tue, Nov 21, 2023 at 10:50:57AM +0100, Thorsten Leemhuis wrote:
> >> * @SCSI maintainers: could you please look into below please?
> >>
> >> * @Stable team: you might want to take a look as well and consider a
> >> revert in 6.1.y (yes, I know, those are normally avoided, but here it
> >> might make sense).
> >>
> >> Hi everyone!
> >>
> >> TLDR: I noticed a regression (Adaptec 71605z with aacraid sometimes
> >> hangs for a while) that was reported months ago already but is still not
> >> fixed. Not only that, it apparently more and more users run into this
> >> recently, as the culprit was recently integrated into 6.1.y; I wonder if
> >> it would be best to revert it there, unless a fix for mainline comes
> >> into reach soon.
> >>
> >> Details:
> >>
> >> Quite a few machines with Adaptec controllers seems to hang for a few
> >> tens of seconds to a few minutes before things start to work normally
> >> again for a while:
> >> https://bugzilla.kernel.org/show_bug.cgi?id=217599
> >>
> >> That problem is apparently caused by 9dc704dcc09eae ("scsi: aacraid:
> >> Reply queue mapping to CPUs based on IRQ affinity") [v6.4-rc7]. That
> >> commit despite a warning of mine to Sasha recently made it into 6.1.53
> >> -- and that way apparently recently reached more users recently, as
> >> quite a few joined that ticket.
> >[...]
> > I am loath to revert a stable patch that has been there for so long as
> > any upgrade will just cause the same bug to show back up. Why can't we
> > just revert it in Linus's tree now and I'll take that revert in the
> > stable trees as well?
> 
> FWIW, I know and in general agree with that strategy, that's why I
> normally wouldn't have brought a stable-only revert up for
> consideration. But this issue to me looked somewhat special and urgent
> for two and a half reasons: (1) that backport apparently made a lot more
> people suddenly hit the issue (2) there was also this data corruption
> aspect one of the reporters mentioned (not sure if that is real and/or
> if this might be just a 6.1.y thing). Furthermore for 6.1.y it was
> recently confirmed that reverting the change fixes things, while we iirc
> had no such confirmation for recent mainline kernels at that point. So
> it looked like it would take a while to get this sorted out in mainline.
> But it seems we finally might get closer to that now, so yeah, maybe
> it's not worth a stable revert.

If I'm not completely wrong, finally indeed the commit has been
reverted in mainline, with c5becf57dd56 ("Revert "scsi: aacraid: Reply
queue mapping to CPUs based on IRQ affinity"") .

This is what was mentioned here:
https://bugzilla.kernel.org/show_bug.cgi?id=217599#c52

So should/can it be reverted it now as well on the 6.1.y stable series
(and the others up as needed?)

#regzbot link: https://bugs.debian.org/1059624
#regzbot fixed-by: c5becf57dd56

Thorsten, hope I got the above right.

Regards,
Salvatore

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