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From:   "NeilBrown" <neilb@suse.de>
To:     "Daire Byrne" <daire@dneg.com>
Cc:     "Trond Myklebust" <trond.myklebust@hammerspace.com>,
        "Anna Schumaker" <Anna.Schumaker@netapp.com>,
        "linux-nfs" <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH/rfc v2] NFS: introduce NFS namespaces.
In-reply-to: <CAPt2mGM6mcqM9orzHuyTVgX2pnG5Y7nLeM85tdZ5LoDO9XozBA@mail.gmail.com>
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Date:   Thu, 08 Jul 2021 07:25:49 +1000
Message-id: <162569314954.31036.11087071768390664533@noble.neil.brown.name>
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On Wed, 07 Jul 2021, Daire Byrne wrote:
> I stripped out all my patches so it's just this one on top of 5.13-rc7
> and I can still reproduce it.
> 
> I can only trigger it by mounting the same export (RHEL7 server) using
> two different namespaces and performing a heavy IO benchmark to either
> mount (leaving one idle). Part of the benchmark walks thousands of
> dirs with files (hence the readdirs).
> 
> If I mount the same server twice with no (same) namespaces, even with
> the patch applied, it works fine without any crash.

That's pretty solid evidence!

I just realized that the stack trace you reported mentions
"kfree_const()".
My latest patch doesn't include that, and nfs doesn't use it at all.
Might you still be using the older patch?

NeilBrown