Re: Re: i686 hang on boot in userspace

[Jens Axboe <axboe@suse.de>]

On Tue, Jul 25 2006, gmu 2k6 wrote:
> On 7/25/06, Jens Axboe <axboe@suse.de> wrote:
> >On Tue, Jul 25 2006, gmu 2k6 wrote:
> >> On 7/25/06, Jens Axboe <axboe@suse.de> wrote:
> >> >On Tue, Jul 25 2006, gmu 2k6 wrote:
> >> >> ok, let's nail it to 2.6.17-git5 instead as it survived git status
> >> >> compared to -git6
> >> >> which seems to have correctly booted by accident the lastime. timing
> >> >issues
> >> >> I guess.
> >> >
> >> >I will try and reproduce it here now. It seems to be in between commit
> >> >271f18f102c789f59644bb6c53a69da1df72b2f4 and commit
> >> >dd67d051529387f6e44d22d1d5540ef281965fdd where the first one could also
> >> >be bad.
> >> >
> >> >I'm assuming that acf421755593f7d7bd9352d57eda796c6eb4fa43 should be
> >> >good, so you can try and verify that
> >> >dd67d051529387f6e44d22d1d5540ef281965fdd is bad and bisect between the
> >> >two. It's only about 6 commits, so should be quick enough to do.
> >>
> >> 1) no luck with remote serial console
> >> 2) netconsole does not work although connecting to the listener with 
> >netcat
> >> and
> >> sending strings works
> >> I'm gonna try via physical rs232 9pins and see how that works.
> >> afterwards I will try to bisect the revisions you mentioned.
> >>
> >> btw, the issue seems to come and go as I managed to boot log into a 
> >.17-git6
> >> kernel or is timing-dependent.
> >
> >I can reproduce it, you don't have to spend more time on bisecting or
> >testing. This should fix it:
> >
> >diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c
> >index 1c4df22..1eac041 100644
> >--- a/drivers/block/cciss.c
> >+++ b/drivers/block/cciss.c
> >@@ -1238,6 +1238,7 @@ static void cciss_softirq_done(struct re
> >        CommandList_struct *cmd = rq->completion_data;
> >        ctlr_info_t *h = hba[cmd->ctlr];
> >        unsigned long flags;
> >+       request_queue_t *q;
> >        u64bit temp64;
> >        int i, ddir;
> >
> >@@ -1260,10 +1261,13 @@ #ifdef CCISS_DEBUG
> >        printk("Done with %p\n", rq);
> > #endif                         /* CCISS_DEBUG */
> >
> >+       q = rq->q;
> >+
> >        add_disk_randomness(rq->rq_disk);
> >        spin_lock_irqsave(&h->lock, flags);
> >        end_that_request_last(rq, rq->errors);
> >        cmd_free(h, cmd, 1);
> >+       blk_start_queue(q);
> >        spin_unlock_irqrestore(&h->lock, flags);
> > }
> >
> >
> >A better fix would rework the start_queue logic entirely in the driver,
> >but the above should get you running for now. I'll take a further look.
> 
> this four-liner seems to fix it:
> - I can boot
> - log in
> - git-status works
> - svn up works
> 
> as my last mail said the 2nd patch with the new function introduced
> did hang cciss
> on driver init before printing any drive info.

The problem with the 4-liner is that it potentially starves some arrays
(in theory). I'll retry the full fix.

> btw, I assume you have systems with SmartArray 6* at your disposal to
> test, right?
> I mean SuSE should have some as a distro vendor.

I do, I have several right here next to me.

-- 
Jens Axboe