From: keith.busch@intel.com (Keith Busch)
Subject: [PATCH 2/2] nvme: protect against race condition in nvme_validate_ns()
Date: Tue, 19 Feb 2019 12:54:33 -0700 [thread overview]
Message-ID: <20190219195433.GE16341@localhost.localdomain> (raw)
In-Reply-To: <5f600cbc-eab7-0c72-5ecf-50a12180082c@grimberg.me>
On Tue, Feb 19, 2019@11:44:41AM -0800, Sagi Grimberg wrote:
> On 2/19/19 4:13 AM, Hannes Reinecke wrote:
> > When subsystems are rapidly reconfigured (or sending out several AENs)
> > we might end up in a situation where several instances of nvme_scan_work()
> > are running. Each of which might be trying to register the same nsid,
> > so nvme_find_get_ns() in nvme_validate_ns() will return 0 for both,
> > resulting in a crash in nvme_alloc_ns() as both are registering a
> > gendisk with the same name.
>
> Wouldn't it be better to serialize nvme_scan_work such that it doesn't
> run multiple times in parallel?
Doesn't the work queue already serialize individual ctrl's scan_work?
There is also a recently added mutex to synchronize scan work with
command effects handling, which would force an nvme_ctrl's scan_work to
be serialized:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e7ad43c3eda6a1690c4c3c341f95dc1c6898da83
next prev parent reply other threads:[~2019-02-19 19:54 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-19 12:13 [PATCH 0/2] nvme: fixup crash in device_add_disk() Hannes Reinecke
2019-02-19 12:13 ` [PATCH 1/2] nvme: return error from nvme_alloc_ns() Hannes Reinecke
2019-02-19 19:42 ` Sagi Grimberg
2019-02-20 14:21 ` Christoph Hellwig
2019-02-19 12:13 ` [PATCH 2/2] nvme: protect against race condition in nvme_validate_ns() Hannes Reinecke
2019-02-19 19:44 ` Sagi Grimberg
2019-02-19 19:54 ` Keith Busch [this message]
2019-02-20 6:52 ` Hannes Reinecke
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