From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Jan Beulich" <JBeulich@novell.com>
Subject: Re: [PATCH] Fix blkback/blktap sysfs read bug.
Date: Tue, 19 Jan 2010 10:25:38 +0000
Message-ID: <4B5596B2020000780002AAF1@vpn.id2.novell.com>
References: <20100119095250.GB20691@joejin-pc.cn.oracle.com>
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>>> "Joe Jin" <joe.jin@oracle.com> 19.01.10 10:52 >>>
>At backend driver blkback and blktap, when checking statistics information=
,
>at the time vbd device remove, kernel will crash.
>
>Below patch will fix it, please review and apply.

This isn't a complete fix if I follow your analysis: There's still a race
between blk{back,tap}_remove() freeing be->blkif/be and the sysfs
code. dev->dev.driver_data (and possibly be->blkif) must be cleared
before freeing it (them).

Jan