Re: panic: System call lstat returning with 1 locks held

On 1/16/08, Scot Hetzel <swhetzel_at_gmail.com> wrote:
> On 1/15/08, Kostik Belousov <kostikbel_at_gmail.com> wrote:
> > On Tue, Jan 15, 2008 at 07:52:12AM -0600, Scot Hetzel wrote:
> > > When I boot a Jan 13th or Jan 15th kernel, and then run
> > > /usr/local/etc/cvsup/update.sh to update the local CVS repository, I
> > > get the following panic:
> > >
> > > panic: System call lstat returning with 1 locks held
> > > cpuid = 0
> > > KDB: enter: panic
> > > [thread ; pid 1240 tid 10031]
> > > stopped at kdb_enter+0x3d: movq $0,0x41b048(%rip)
> > > db> show alllocks
> > > db> show locks
> > > db> bt
> > > tracing pid 1240 tid 10031 td 0xffffff001c1ad360
> > > kdb_enter() at kdb_enter+0x3d
> > > panic() at panic+0x176
> > > syscalls() at syscalls+0x66d
> > > Xfast_syscalls() at Xfast_syscalls+0xab
> > > --- syscall (0, FreeBSD ELF64, nosys), rip = 0x8009e87ec, rsp=
> > > 0x72ec50, rbp = 0x72ed28 ---
> > >
> > I think this could be related to the recent vn_lock()/VOP_LOCK() KPI changes.
> > Please, add DEBUG_VFS_LOCKS to the kernel config, and do the
> >         show lockedvnods
> > from the ddb prompt when the panic occurs. The witness does not track
> > the lockmgr locks.
> >
> I added DEBUG_VFS_LOCKS to the kernel config file, rebuilt and
> installed the kernel.  After rebooting the system, I started the cvsup
> update for my local mirror, when the panic occured I received a
> similar panic to the one above.  When I used 'show lockedvnods' the
> only thing that was displayed was 'Locked vnodes' and that was it.
>
> I'm going to try a binary search to see if I can narrow the problem down.
>
> Scot
>
I found the point where the problem occurs.  If I update /usr/src/sys
to Jan 08 23:45 UTC 2008, then I don't get the lstat panic.  But when
I update to Jan 08 23:49 UTC 2008, the panic returns.

These are the files that change between these times:

dev/usb/ehci.c:
     $FreeBSD: src/sys/dev/usb/ehci.c,v 1.57 2008/01/08 23:48:30 attilio Exp $

dev/usb/if_udav.c:
     $FreeBSD: src/sys/dev/usb/if_udav.c,v 1.34 2008/01/08 23:48:30
attilio Exp $

fs/hpfs/hpfs_subr.h:
     $FreeBSD: src/sys/fs/hpfs/hpfs_subr.h,v 1.4 2008/01/08 23:48:31
attilio Exp $

fs/ntfs/ntfs_subr.c:
     $FreeBSD: src/sys/fs/ntfs/ntfs_subr.c,v 1.43 2008/01/08 23:48:31
attilio Exp $

kern/kern_lock.c:
     $FreeBSD: src/sys/kern/kern_lock.c,v 1.117 2008/01/08 23:48:31
attilio Exp $

sys/buf.h:
     $FreeBSD: src/sys/sys/buf.h,v 1.197 2008/01/08 23:48:31 attilio Exp $

sys/lockmgr.h:
     $FreeBSD: src/sys/sys/lockmgr.h,v 1.56 2008/01/08 23:48:31 attilio Exp $


Scot