From: "Benjamin Coddington" <bcodding@redhat.com>
To: "Cristian Marussi" <cristian.marussi@arm.com>
Cc: "Punit Agrawal" <punit.agrawal@arm.com>,
"Linux NFS Mailing List" <linux-nfs@vger.kernel.org>
Subject: Re: [aarch64] refcount_t: use-after-free in NFS with 64k pages
Date: Tue, 05 Feb 2019 07:14:18 -0500 [thread overview]
Message-ID: <9C25D1F9-3A25-4CF3-822E-CE25829642D9@redhat.com> (raw)
In-Reply-To: <e99fd27b-9e60-22fc-af6b-da93b0e0ca0f@arm.com>
On 5 Feb 2019, at 7:10, Cristian Marussi wrote:
> Hi Ben
>
> On 05/02/2019 11:53, Benjamin Coddington wrote:
>> Hello Cristian and Punit,
>>
>> Did you ever get to the bottom of this one? We just saw this on one
>> run
>> of our 4.18.0-era ppc64le, and I'm wondering if we ever found the
>> root
>> cause.
>
> unfortunately I stopped working actively on finding the root cause,
> since I've
> found a viable workaround that let us unblock our broken LTP runs.
>
> Setting wsize=65536 in NFS bootparams completely solves the issue with
> 64k pages
> (and does NOT break 4k either :D): this confirmed my hyp that there is
> some sort
> of race when accounting refcounts during the lifetime of nfs_page
> structs which
> leads to a misscounted refcount...but as I said I never looked back
> into that
> again (but never say never...)
>
> Hope this helps...
Hmm, interesting..
Will you share your reproducer with me? That will save me some time.
Ben
next prev parent reply other threads:[~2019-02-05 12:14 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-19 14:48 [aarch64] refcount_t: use-after-free in NFS with 64k pages Cristian Marussi
2018-10-19 15:18 ` Punit Agrawal
2018-10-19 15:35 ` Cristian Marussi
2019-02-05 11:53 ` Benjamin Coddington
2019-02-05 12:10 ` Cristian Marussi
2019-02-05 12:14 ` Benjamin Coddington [this message]
2019-02-05 12:37 ` Cristian Marussi
2019-02-05 12:50 ` Cristian Marussi
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