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From: Nhat Pham <nphamcs@gmail.com>
To: Chris Murphy <lists@colorremedies.com>
Cc: Linux List <linux-mm@kvack.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	 Yosry Ahmed <yosryahmed@google.com>,
	Yosry Ahmed <yosry.ahmed@linux.dev>
Subject: Re: 6.14.0-rc6 lockdep warning kswapd
Date: Thu, 20 Mar 2025 21:28:12 -0700	[thread overview]
Message-ID: <CAKEwX=Mm22Xi_8B1j1RV_PNZ5Z6bGYR=qLhcSYQFMMUOJLgGrg@mail.gmail.com> (raw)
In-Reply-To: <3f156789-759e-4195-8881-c5c74ced85d4@app.fastmail.com>

On Wed, Mar 19, 2025 at 9:31 PM Chris Murphy <lists@colorremedies.com> wrote:
>
>
>
> On Wed, Mar 12, 2025, at 9:52 PM, Chris Murphy wrote:
> > 6.14.0-0.rc6.49.fc42.x86_64+debug
> > swap is enabled using a swapfile on btrfs (which is also used for /)
> > zswap is enabled using zsmalloc/zstd
> >
> > Downstream bug report includes full dmesg.log attachment
> > https://bugzilla.redhat.com/show_bug.cgi?id=2351794
>
> Also occurs with 6.14.0-0.rc7.56.fc42.x86_64
>
> It's not reproducible in any way I'm aware of, but isn't uncommon. Updated bug report with rc7 dmesg.
>
>
> --
> Chris Murphy
>

Eyeballing the trace, this looks awfully similar to the problem that
Yosry was fixing here:

https://lore.kernel.org/all/20250226185625.2672936-1-yosry.ahmed@linux.dev/

That should break the following link in the chain:

&per_cpu_ptr(pool->acomp_ctx, cpu)->mutex --> scomp_lock

since we release the first lock, before acquiring the second lock.

I don't think this is in rc6 yet. Can you apply the patch and test again?


  reply	other threads:[~2025-03-21  4:28 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-03-13  3:52 Chris Murphy
2025-03-20  4:31 ` Chris Murphy
2025-03-21  4:28   ` Nhat Pham [this message]
2025-03-21 18:57     ` Yosry Ahmed
2025-03-21 23:24     ` Chris Murphy
2025-03-24 17:06       ` Nhat Pham
2025-03-24 18:24         ` Yosry Ahmed

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