From: hch@infradead.org (Christoph Hellwig)
Subject: [PATCH v2] nvmet: Fix fatal_err_work deadlock
Date: Mon, 23 Oct 2017 07:50:13 -0700 [thread overview]
Message-ID: <20171023145013.GA3017@infradead.org> (raw)
In-Reply-To: <a1123d71-51f8-1d72-3e5d-67f23634543a@grimberg.me>
On Mon, Oct 23, 2017@02:05:08PM +0300, Sagi Grimberg wrote:
> Regardless of flush_work or cancel_work_sync, its a deadlock
> in fc.
>
> in rdma/loop we always call ->free_ctrl from a different context.
>
> In rdma we do that from the rdma_cm context, in loop we schedule
> host side delete on nvme_wq, in fc apparently we can get to
> free_ctrl directly from that context.
Yes, nvmet_fc_delete_ctrl -> nvmet_fc_delete_target_assoc ->
nvmet_fc_delete_target_queue.
> If fatal_err_work calls ->delete_ctrl() and that in turn gets to put the
> last reference on the ctrl it will end up in ->free_ctrl() under
> fatal_err_work context which will then try to flush fatal_err_work.
Yes, and the way I understand flush_work that is perfectly fine for
flush_work, just not for cancel_work_sync.
next prev parent reply other threads:[~2017-10-23 14:50 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-20 16:12 [PATCH v2] nvmet: Fix fatal_err_work deadlock James Smart
2017-10-23 8:28 ` Christoph Hellwig
2017-10-23 11:05 ` Sagi Grimberg
2017-10-23 14:50 ` Christoph Hellwig [this message]
2017-10-24 7:31 ` Sagi Grimberg
2017-10-24 17:55 ` James Smart
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