Re: panic in vfs_lookup/kern_statat_vnhook?

John Baldwin wrote:
> On Tuesday, May 22, 2012 2:36:06 pm Ian FREISLICH wrote:
> > Hi
> > 
> > I've had quite a few reproduceable panics that look to be VFS
> > related.  The trigger is relatively heavy concurrent disk IO.
> > I can trigger it easily two ways:
> > 
> > 1. running my backup script which essentially does:
> > 	cd /; rsync --one-file-system --delete -aHv . /backup
> > 	cd /tmp; rsync --one-file-system --delete -aHv . /backup/tmp
> > 	cd /usr; rsync --one-file-system --delete -aHv . /backup/usr
> > 	cd /var; rsync --one-file-system --delete -aHv . /backup/var
> > 
> > 2. While updating with cvsup or csup, launch firefox.
> > 
> > Both reliably provoke the panic:
> > 
> > #0  doadump (textdump=1) at pcpu.h:244
> > #1  0xc06aa895 in kern_reboot (howto=260)
> >     at /usr/src/sys/kern/kern_shutdown.c:454
> > #2  0xc06aad36 in panic (fmt=Variable "fmt" is not available.
> > ) at /usr/src/sys/kern/kern_shutdown.c:642
> > #3  0xc087adee in trap_fatal (frame=0xedb365c8, eva=28)
> >     at /usr/src/sys/i386/i386/trap.c:1022
> > #4  0xc087aed8 in trap_pfault (frame=0xedb365c8, usermode=0, eva=28)
> >     at /usr/src/sys/i386/i386/trap.c:875
> > #5  0xc087bc4d in trap (frame=0xedb365c8) at /usr/src/sys/i386/i386/trap.c:
546
> > #6  0xc086687c in calltrap () at /usr/src/sys/i386/i386/exception.s:169
> > #7  0xc0878682 in pmap_enter (pmap=0xc09e4060, va=3359633408, access=7 '\a'
, 
> >     m=0xc3073f70, prot=7 '\a', wired=1) at /usr/src/sys/i386/i386/pmap.c:15
96
> 
> This is the actual panic.  Can you go to this frame?  The VFS bits don't
> matter, the pmap code blew up trying to malloc another vnode.

(kgdb) frame 7
#7  0xc0878682 in pmap_enter (pmap=0xc09e4060, va=3359633408, access=7 '\a', 
    m=0xc191bf70, prot=7 '\a', wired=1) at /usr/src/sys/i386/i386/pmap.c:1596
1596                    root = vm_page_splay(mpte->pindex, root);
(kgdb) l
1591            root = pmap->pm_root;
1592            if (root == NULL) {
1593                    mpte->left = NULL;
1594                    mpte->right = NULL;
1595            } else {
1596                    root = vm_page_splay(mpte->pindex, root);
1597                    if (mpte->pindex < root->pindex) {
1598                            mpte->left = root->left;
1599                            mpte->right = root;
1600                            root->left = NULL;

Ian

-- 
Ian Freislich