From: hch@lst.de (Christoph Hellwig)
Subject: [PATCH 2/3] nvme: shorten race window in nvme_ns_remove()
Date: Wed, 27 Mar 2019 15:02:51 +0100 [thread overview]
Message-ID: <20190327140251.GA25990@lst.de> (raw)
In-Reply-To: <20190327080929.27918-3-hare@suse.de>
On Wed, Mar 27, 2019@09:09:28AM +0100, Hannes Reinecke wrote:
> nvme_ns_remove() sets the 'NVME_NS_REMOVING' bit at first, but
> only removes the namespace from the list at the very end.
> This opens a rether large race window during which other processes
> traversing the namespaces via list_for_each() will access partially
> deleted namespaces, causing unpredictable results.
> This patch shortens the race window by removing the namespace
> from the list as early as possible.
>
> Signed-off-by: Hannes Reinecke <hare at suse.com>
With this patch I don't see any reason for your patch 1, given that
the window between setting the REMOVING bit and removing from the
list is so tiny.
That being said I think we really should also remove the namespace
from ->siblings and clear the current path ASAP as well, which might
remove the need for patch 3 as well.
next prev parent reply other threads:[~2019-03-27 14:02 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-27 8:09 [PATCH 0/3] nvme: fixup race with namespace removal Hannes Reinecke
2019-03-27 8:09 ` [PATCH 1/3] nvme: do not quiesce or unquiesce invalid namespaces Hannes Reinecke
2019-03-27 8:09 ` [PATCH 2/3] nvme: shorten race window in nvme_ns_remove() Hannes Reinecke
2019-03-27 14:02 ` Christoph Hellwig [this message]
2019-03-27 14:41 ` Hannes Reinecke
2019-03-27 14:20 ` Keith Busch
2019-03-27 15:12 ` Hannes Reinecke
2019-03-27 18:50 ` James Smart
2019-03-28 9:27 ` Hannes Reinecke
2019-03-28 11:07 ` Ming Lei
2019-03-28 11:48 ` Hannes Reinecke
2019-03-28 12:11 ` Hannes Reinecke
2019-03-28 15:19 ` Ming Lei
2019-03-28 15:56 ` James Smart
2019-03-28 15:46 ` James Smart
2019-03-28 15:57 ` Hannes Reinecke
2019-03-28 17:50 ` James Smart
2019-03-28 15:05 ` James Smart
2019-03-28 15:50 ` Hannes Reinecke
2019-03-29 0:40 ` Ming Lei
2019-03-27 8:09 ` [PATCH 3/3] nvme-multipath: test namespace state when selecting a new path Hannes Reinecke
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