[cam] mpt stuck in loop attempting to abort

[G. Paul Ziemba]

I'm hoping someone can help me troubleshoot this. I can patch
and build the kernel but I don't know enough about SCSI to know
where to begin.

Running FreeBSD 10.1-STABLE r280974M (so it includes the recent sa(4)
updates). Dell Powervault 122T (LTO2) library is attached to the LSI
scsi adaptor (no other device on the scsi bus). 

After powering on the tape library and doing "camcontrol rescan 1",
there is an endless loop of:

    mpt0: attempting to abort req 0xfffffe0000fe2020:1145 function 0
    mpt0: abort of req 0xfffffe0000fe1148:1120 completed

until I power off the drive. It happens only some of the time, so
perhaps a race condition somewhere?

More details at:

    https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=201157

thanks!
-- 
G. Paul Ziemba
FreeBSD unix:
10:36AM  up 12:21, 3 users, load averages: 1.23, 1.08, 0.97