mps(4) blocks panic-reboot

[Stephen Mcconnell]

Thanks Harry. I'll need to do some testing here to see if I can figure it
out.

Steve

> -----Original Message-----
> From: Harry Schmalzbauer [mailto:freebsd at omnilan.de]
> Sent: Friday, June 02, 2017 10:58 AM
> To: Kenneth D. Merry
> Cc: Stephen Mcconnell; freebsd-scsi at FreeBSD.ORG; Scott Long
> Subject: Re: mps(4) blocks panic-reboot
>
>  Bezüglich Harry Schmalzbauer's Nachricht vom 02.06.2017 18:56
(localtime):
> > Bezüglich Kenneth D. Merry's Nachricht vom 02.06.2017 17:37
(localtime):
> >> On Fri, Jun 02, 2017 at 14:30:44 +0200, Harry Schmalzbauer wrote:
> > …
> >>> KDB: stack backtrace:
> >>> #0 0xffffffff805df4f7 at kdb_backtrace+0x67
> >>> #1 0xffffffff8059df96 at vpanic+0x186
> >>> #2 0xffffffff8059de03 at panic+0x43
> >>> #3 0xffffffff808a1892 at trap_fatal+0x322
> >>> #4 0xffffffff808a18e9 at trap_pfault+0x49
> >>> #5 0xffffffff808a1126 at trap+0x286
> >>> #6 0xffffffff80887401 at calltrap+0x8
> >>> #7 0xffffffff805800f2 at __mtx_unlock_sleep+0x72
> >>> #8 0xffffffff8029a7dc at xpt_polled_action+0x31c
> >>> #9 0xffffffff80416c2b at mpssas_ir_shutdown+0x51b
> >>> #10 0xffffffff8059db9a at kern_reboot+0x49a
> >>> #11 0xffffffff8059d6f8 at sys_reboot+0x458
> >>> #12 0xffffffff808a23f4 at amd64_syscall+0x6c4
> >>> #13 0xffffffff808876eb at Xfast_syscall+0xfb
> >>>
> >>> (kgdb) list *0xffffffff805f43ec
> >>> 0xffffffff805f43ec is in turnstile_broadcast
> >>> (/usr/local/share/deploy-
> tools/RELENG_11/src/sys/kern/subr_turnstile.c:837).
> >>> 832
> >>> 833             /*
> >>> 834              * Transfer the blocked list to the pending list.
> >>> 835              */
> >>> 836             mtx_lock_spin(&td_contested_lock);
> >>> 837             TAILQ_CONCAT(&ts->ts_pending,
&ts->ts_blocked[queue],
> >>> td_lockq);
> >>> 838             mtx_unlock_spin(&td_contested_lock);
> >>> 839
> >>> 840             /*
> >>> 841              * Give a turnstile to each thread.  The last thread
gets
> >>>
> >>> I haven't looked at the code at all and only very briefly lokked at
> >>> the diff, just out of curiosity, like pigs staring at clockworks ;-)
> >>>
> >>> But at least I hope this report does help.
> >> Thanks for testing it!
> >>
> >> My guess is that the problem is that the problem is
> >> xpt_polled_action() releases the device mutex, but
> >> mpssas_SSU_to_SATA_devices() isn't acquiring the mutex.
> >>
> >> You could try putting the following around the call to
xpt_polled_action():
> >>
> >> 	mtx_lock(xpt_path_mtx(ccb->ccb_h.path));
> >> 	xpt_polled_action(ccb);
> >> 	mtx_unlock(xpt_path_mtx(ccb->ccb_h.path));
> >>
> >> See if that fixes things.  One other thing to put in there -- after
> >> the if (target->stop_at_shutdown) { } statement, but still inside the
> >> for loop, add these two lines:
> >>
> >> 	xpt_free_path(ccb->ccb_h.path);
> >> 	xpt_free_ccb(ccb);
> >
> > Jope I didn't mess up with text editing, pleas see the attached hunk
> > if it corresponds to the (additional) chages to Stephen's diff.
>
> Sorry, now really with attachment...