On Mon, 2012-08-27 at 12:13 -0400, John Drescher wrote:
> >> I have bisected it down to the following patch:
> >>
> >> Bisecting: 0 revisions left to test after this (roughly 0 steps)
> >> [10f8d5b86743b33d841a175303e2bf67fd620f42] SCSI: fix hot unplug vs
> >> async scan race
> >>
> >> It appears this patch caused the bad behavior although I have not
> >> tested that yet. I am rebuilding the array (takes ~2 hours) from the
> >> previous good bisect.
> >>
> 
> Confirmed. This patch appears to cause the bug in my test setup.
> 
> [  339.406778] BUG: soft lockup - CPU#2 stuck for 23s! [kworker/u:8:2202]
[..]
> [  339.415268]  [<ffffffff8141782a>] scsi_remove_target+0xda/0x1f0

I wonder if we are preventing scsi_device_dev_release_usercontext() from
making forward progress?

...the attached patch should confirm this or give more info otherwise.

--
Dan