From: Christoph Hellwig <hch@infradead.org>
To: Christian L?hle <CLoehle@hyperstone.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>,
"martin.petersen@oracle.com" <martin.petersen@oracle.com>,
"jejb@linux.ibm.com" <jejb@linux.ibm.com>,
"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH] sd: sd_open: prevent device removal during sd_open
Date: Fri, 3 Sep 2021 05:38:34 +0100 [thread overview]
Message-ID: <YTGmyp0kzhVsuk5K@infradead.org> (raw)
In-Reply-To: <98bfca4cbaa24462994bcb533d365414@hyperstone.com>
On Thu, Sep 02, 2021 at 01:57:13PM +0000, Christian L?hle wrote:
> sd and parent devices must not be removed as sd_open checks for events
>
> sd_need_revalidate and sd_revalidate_disk traverse the device path
> to check for event changes. If during this, e.g. the scsi host is being
> removed and its resources freed, this traversal crashes.
> Locking with scan_mutex for just a scsi disk open may seem blunt, but there
> does not seem to be a more granular option. Also opening /dev/sdX directly
> happens rarely enough that this shouldn't cause any issues.
Can you please root cause how the device could not be valid, as that
should not happen?
>
> The issue occurred on an older kernel with the following trace:
> stack segment: 0000 [#1] PREEMPT SMP PTI
> CPU: 1 PID: 121457 Comm: python3 Not tainted 4.14.238hyLinux #1
.. preferably with a current mainline kernel as things changed a lot
in this area.
next prev parent reply other threads:[~2021-09-03 4:39 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-02 13:57 Christian Löhle
2021-09-02 14:23 ` Greg KH
2021-09-03 4:38 ` Christoph Hellwig [this message]
2021-09-03 10:09 ` AW: " Christian Löhle
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