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From: Will Deacon <will@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>,
	Mohamed Alzayat <alzayat@mpi-sws.org>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	linux-mm@kvack.org
Subject: Re: Potential bug in soft-dirty bits (with test case)
Date: Mon, 30 Nov 2020 12:50:46 +0000	[thread overview]
Message-ID: <20201130125045.GG24563@willie-the-truck> (raw)
In-Reply-To: <20201130120241.GP3040@hirez.programming.kicks-ass.net>

On Mon, Nov 30, 2020 at 01:02:41PM +0100, Peter Zijlstra wrote:
> On Mon, Nov 30, 2020 at 12:51:59PM +0100, Vlastimil Babka wrote:
> > On 11/30/20 11:37 AM, Mohamed Alzayat wrote:
> 
> > > Thanks for confirming, Vlastimil!
> > > 
> > > The first bad commit is: 0758cd8304942292e95a0f750c374533db378b32
> > > asm-generic/tlb: avoid potential double flush
> > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=0758cd8304942292e95a0f750c374533db378b32
> > > 
> > > Reverting this commit solves the problem, but this might not be the
> > > right way of fixing it.
> > 
> > Thanks for bisecting! Let's CC people involved in that commit. All important
> > should be in the quoted conversation above.
> 
> There's a thread about it here:
> 
>   https://lkml.kernel.org/r/20201120143557.6715-1-will@kernel.org
> 
> That softdirty code really shouldn't be using mmu_gather imo, but I'm
> still not clear on what exactly is broken why there.

I'll spin a v2 of that series soon, so I'll add folks here to cc. The
fact that a test noticed the missing invalidation is a pretty good reason
for us to add it back!

Will


  reply	other threads:[~2020-11-30 12:50 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-25 14:15 Mohamed Alzayat
2020-11-27 16:40 ` Vlastimil Babka
2020-11-30 10:37   ` Mohamed Alzayat
2020-11-30 11:51     ` Vlastimil Babka
2020-11-30 12:02       ` Peter Zijlstra
2020-11-30 12:50         ` Will Deacon [this message]
2021-04-20 18:32           ` Mohamed Alzayat

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