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SubjectRE: [SCSI BUG 2.6.15-rc3-mm1] scheduling while atomic on boot tim e
Date


> -----Original Message-----
> From: James Bottomley [mailto:James.Bottomley@SteelEye.com]
> Sent: Monday, December 05, 2005 3:32 PM
> To: goggin, edward
> Cc: 'Andrew Morton'; Wu Fengguang;
> linux-kernel@vger.kernel.org; linux-scsi@vger.kernel.org
> Subject: RE: [SCSI BUG 2.6.15-rc3-mm1] scheduling while
> atomic on boot tim e
>
> On Fri, 2005-12-02 at 15:35 -0500, goggin, edward wrote:
> > I think this is caused by my patch to scsi_next_command()
> > (on or about 11/11) causing it to call put_device() and
> > invoke the kobject's release() function while in soft
> > interrupt. My patch should be removed ... although I
> > don't have an alternate solution in mind for the original
> > problem which was an "oops with USB Storage on 2.6.14".
>
> Yes and no.
>
> Reverting your patch won't fix the problem because scsi_put_command()
> will then relinquish the last reference to the device and trigger the
> same warning. Additionally, blk_run_queue now stands a good chance of
> running on a freed queue which could trigger a panic.
>
> The problem seems to be that device_del() is apparently requiring user
> context, if that's true, this will bite us not only here, but all over
> the place

like as a result of the call to put_device() at the bottom of
scsi_request_fn() when called indirectly via scsi_next_command()'s
call to scsi_run_queue()

> ... in fact the fix might have to be to do the target reap
> through a workqueue.
>
> Regardless, your patch isn't the culprit here, it's just the
> thing which
> is doing the last put.
>
> James
>
>
>
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