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Date:      Thu, 7 Jun 2001 18:08:09 -0400 (EDT)
From:      Andrew Gallatin <gallatin@cs.duke.edu>
To:        John Baldwin <jhb@FreeBSD.ORG>
Cc:        alfred@FreeBSD.ORG, freebsd-alpha@FreeBSD.ORG
Subject:   RE: Wow, have I got a stack for you!
Message-ID:  <15135.64329.476219.457169@grasshopper.cs.duke.edu>
In-Reply-To: <XFMail.010607145148.jhb@FreeBSD.org>
References:  <15135.58016.753596.764419@grasshopper.cs.duke.edu> <XFMail.010607145148.jhb@FreeBSD.org>

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John Baldwin writes:
 > > hardclock() at hardclock+0x308
 > 
 > (kgdb) l *hardclock+0x308
 > 0xfffffc00003b6248 is in hardclock (../../kern/kern_clock.c:213).
 > 213             mtx_lock_spin(&callout_lock);
 > 
 > Cute, ok.  Is that possibly missing a frame?

It seems more likely that the pmap is trashed.  I tried to get a dump,
but it kept faulting nearly every time it looked up a mapped (non
K0SEG) address.

 > > handleclock() at handleclock+0x22c
 > > alpha_clock_interrupt() at alpha_clock_interrupt+0x68
 > > interrupt() at interrupt+0xb8
 > > XentInt() at XentInt+0x28
 > > --- interrupt (from ipl 0) ---
 > > siocntxwait() at siocntxwait+0x50
 > > siocnclose() at siocnclose+0x30
 > > siocnputc() at siocnputc+0x98
 > > cnputc() at cnputc+0x4c
 > > putchar() at putchar+0xf4
 > > kvprintf() at kvprintf+0xcc
 > > printf() at printf+0xac
 > 
 > Now this is the first trap with a NULL pointer deref, right?

Impossible to tell.  I personally suspect that pmap_insert_entry()
faulted on a (more or less) NULL deref.

 > > printtrap() at printtrap+0x100
 > > trap() at trap+0x1214
 > > XentMM() at XentMM+0x2c
 > > --- memory management fault ---
 > > vm_fault1() at vm_fault1+0x1d8
 > 
 > (kgdb) l *vm_fault1+0x1d8
 > 0xfffffc00005707f8 is in vm_fault1 (../../vm/vm_object.h:198).
 > 197             mtx_assert(VM_OBJECT_MTX(object), MA_OWNED);
 > 198             object->paging_in_progress += i;
 > 
 > Ok, this is the same exact panic I've been getting on the SMP system.  The
 > vm_map_lookup() is somehow returning a fs.first_object of NULL. :(  Well,
 > possibly.  I've got a bunch of extra assertions in my SMP kernel but it hasn't
 > hit them yet.  It just had it's own nested panic deal off somewhere else. *sigh*
 > 
 > > vm_fault() at vm_fault+0x204
 > > trap() at trap+0xfc8
 > > XentMM() at XentMM+0x2c
 > > --- memory management fault ---
 > > pmap_insert_entry() at pmap_insert_entry+0x6c
 > 
 > (kgdb) l *pmap_insert_entry+0x6c
 > 0xfffffc00005b532c is in pmap_insert_entry (../../alpha/alpha/pmap.c:1769).
 > 1769            TAILQ_INSERT_TAIL(&m->md.pv_list, pv, pv_list);
 > 
 > ?  *shrug*
 > 

Memory looks to be seriously corrupted..

Drew

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