From: Ilya Dryomov <idryomov@gmail.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: "Lucas Stach" <l.stach@pengutronix.de>,
"Ceph Development" <ceph-devel@vger.kernel.org>,
linux-xfs@vger.kernel.org,
"Michael Olbrich" <m.olbrich@pengutronix.de>,
"Björn Lässig" <b.laessig@pengutronix.de>
Subject: Re: XFS on RBD deadlock
Date: Tue, 29 Nov 2016 14:19:07 +0100 [thread overview]
Message-ID: <CAOi1vP8Od6RgNchXGsXP3gs-6P0x9ZTS7dVfpsmfuDMZm2ZyHg@mail.gmail.com> (raw)
In-Reply-To: <20161129120405.GA11089@infradead.org>
On Tue, Nov 29, 2016 at 1:04 PM, Christoph Hellwig <hch@infradead.org> wrote:
> On Tue, Nov 29, 2016 at 12:17:08PM +0100, Lucas Stach wrote:
>> 2. RBD worker is trying to handle the XFS block request, but the
>> involved crypto code recurses into the XFS superblock shrinker, as it's
>> trying to allocate memory with GFP_KERNEL in __crypto_alloc_tfm.
>
> And that's where the issues start - crypto_alloc_skcipher and friends
> are not intended to be called from the writeback path.
Yeah, and to worsen things it's allocated and then destroyed on *every*
write. I'm in the process of re-writing that code for CONFIG_VMAP_STACK
and will look into fixing this as well.
In the meantime, disabling cephx message signing should take that
allocation out of the way.
Thanks,
Ilya
prev parent reply other threads:[~2016-11-29 13:19 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-29 11:17 XFS on RBD deadlock Lucas Stach
2016-11-29 12:04 ` Christoph Hellwig
2016-11-29 13:19 ` Ilya Dryomov [this message]
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