From: Dave Chinner <david@fromorbit.com>
To: Vlad Bespalov <vlad.botanic@gmail.com>
Cc: xfs@oss.sgi.com
Subject: Re: possible null pointer in xlog_iodone
Date: Sat, 15 Jun 2013 11:03:13 +1000 [thread overview]
Message-ID: <20130615010313.GA29338@dastard> (raw)
In-Reply-To: <CA+aXbB5ohJkDde8qJSE0AU6B0dh59YjNPVfxVjXCOg73k7ihXQ@mail.gmail.com>
On Fri, Jun 14, 2013 at 09:15:04PM +0400, Vlad Bespalov wrote:
> i`m running an xfs filesystem over device going offline/online and
> sometimes offline may be done in parallel with unmounting
>
> at some point i got several crashes with null pointer panic in
> xlog_iodone: xlog_t structure taken from input buffer is null
>
> i wonder if the following call path combined with disk online/offline
> handling could have led to this crash:
>
> --------------
> xfs_unmountfs()
> xfs_log_unmount_write(mp)
> xlog_state_release_iclog(log)
> xlog_sync(log, iclog = log->l_iclog)
> (bp=iclog->ic_bp)
> xlog_bdstrat(bp)
> (iclog->ic_state != XLOG_STATE_ERROR ? )
> xfs_buf_iorequest(bp)
> xfs_buf_ioend (called with scheduling (*) )
> (queues : bp->b_iodone_work,
> callback: xlog_iodone)
Which is followed by:
if (!(iclog->ic_state == XLOG_STATE_ACTIVE ||
iclog->ic_state == XLOG_STATE_DIRTY)) {
if (!XLOG_FORCED_SHUTDOWN(log)) {
xlog_wait(&iclog->ic_force_wait,
&log->l_icloglock)
Which is supposed to wait for the log IO to complete and hence
xlog_iodone() is supposed to have been run by the time this code
completes.
What kernel are you tesing on? Do you have a script that reproduces
it?
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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next prev parent reply other threads:[~2013-06-15 1:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-14 17:15 possible null pointer in xlog_iodone Vlad Bespalov
2013-06-14 19:42 ` Mark Tinguely
2013-06-15 1:03 ` Dave Chinner [this message]
2013-06-17 14:38 ` Vlad Bespalov
2013-06-18 0:19 ` Dave Chinner
2013-06-18 0:37 ` Vlad Bespalov
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