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From: Nathan Chancellor <natechancellor@gmail.com>
To: Ben Hutchings <ben.hutchings@codethink.co.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Sasha Levin <sashal@kernel.org>,
	Sasha Levin <Alexander.Levin@microsoft.com>,
	stable <stable@vger.kernel.org>
Subject: Re: [stable] locks: fix a potential use-after-free problem when wakeup a waiter
Date: Thu, 19 Mar 2020 22:41:30 -0700	[thread overview]
Message-ID: <20200320054130.GA9611@ubuntu-m2-xlarge-x86> (raw)
In-Reply-To: <500c8174c171378e8b6802ad70b4bf5563b3fab0.camel@codethink.co.uk>

On Thu, Mar 19, 2020 at 07:27:56PM +0000, Ben Hutchings wrote:
> On Thu, 2020-03-19 at 07:37 +0100, Greg Kroah-Hartman wrote:
> > On Wed, Mar 18, 2020 at 06:29:06PM -0400, Sasha Levin wrote:
> > > On Wed, Mar 18, 2020 at 10:09:20PM +0000, Ben Hutchings wrote:
> > > > This commit (included in 5.6-rc5) seems to be needed for 5.4 and 5.5
> > > > branches:
> > > > 
> > > > commit 6d390e4b5d48ec03bb87e63cf0a2bff5f4e116da
> > > > Author: yangerkun <yangerkun@huawei.com>
> > > > Date:   Wed Mar 4 15:25:56 2020 +0800
> > > > 
> > > >    locks: fix a potential use-after-free problem when wakeup a waiter
> > > 
> > > I've queued it up for 5.5 and 5.4, thanks!
> > > 
> > > > I'm a bit surprised that it hasn't yet been applied, while some fixes
> > > > from 5.6-rc6 have.
> > > 
> > > Greg, I wonder if it makes sense to have you push a "Greg is here
> > > --->" "bookmark" in the form of a tag/branch on linux-stable-rc.git? at
> > > the very least it'll make it easy to see if something was missed or
> > > still waiting in the queue.
> > 
> > To quote Jeff Layton:
> > 
> > 	Hi Greg, there is a performance regression with this patch. We're
> > 	sorting through potential ways to address it at the moment, but you may
> > 	want to hold off until we have a fix for that merged.
> > 	
> > 	Sorry for the hassle!
> > 
> > Which is why I dropped it for now.
> > 
> > I'll go drop it again :)
> 
> I didn't see any mention of this on the stable list though.
> I also don't think that a performance regression outweighs the
> seriousness of the bug being fixed.
> 
> Ben.
> 

Looks like a fix for the performance regression was committed yesterday
to mainline.

dcf23ac3e846c ("locks: reinstate locks_delete_block optimization")

Cheers,
Nathan

  reply	other threads:[~2020-03-20  5:41 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-18 22:09 [stable] locks: fix a potential use-after-free problem when wakeup a waiter Ben Hutchings
2020-03-18 22:29 ` Sasha Levin
2020-03-19  6:37   ` Greg Kroah-Hartman
2020-03-19 19:27     ` Ben Hutchings
2020-03-20  5:41       ` Nathan Chancellor [this message]
2020-03-22  1:55         ` Sasha Levin

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