panic: mutex Giant owned at nfs_syscalls.c:556
pluknet at gmail.com
Thu Feb 21 12:31:23 UTC 2008
On 21/02/2008, Kris Kennaway <kris at freebsd.org> wrote:
> pluknet wrote:
> > I got this assertion while attempting to remove file on nfs mounted
> > ffs filesystem.
> > NFS client on 7.0-PRERELEASE and NFS server on 8-CURRENT.
> > FreeBSD 7.0-PRERELEASE #1: Wed Feb 6 18:09:18 MSK 2008
> > FreeBSD 8.0-CURRENT #9: Fri Feb 15 14:31:07 MSK 2008
> > Unread portion of the kernel message buffer:
> > panic: mutex Giant owned at
> > /usr/src/sys/modules/nfsserver/../../nfsserver/nfs_syscalls.c:556
> > KDB: enter: panic
> > exclusive sleep mutex nfsd_mtx r = 0 (0xc41d1660) locked @
> > /usr/src/sys/modules/nfsserver/../../nfsserver/nfs_syscalls.c:501
> > exclusive sleep mutex Giant r = 0 (0xc07e6410) locked @
> > /usr/src/sys/kern/vfs_lookup.c:663
> > ...
> > #9 0xc053959d in panic (fmt=0xc076181d "mutex %s owned at %s:%d")
> > at /usr/src/sys/kern/kern_shutdown.c:555
> > #10 0xc052adf7 in _mtx_assert (m=0xc07e6410, what=0,
> > file=0xc41cb7b2
> > "/usr/src/sys/modules/nfsserver/../../nfsserver/nfs_syscalls.c",
> > line=556) at /usr/src/sys/kern/kern_mutex.c:652
> > #11 0xc41c9e82 in nfssvc (td=0xc2e68000, uap=0xd600dcfc)
> > at /usr/src/sys/modules/nfsserver/../../nfsserver/nfs_syscalls.c:556
> > #12 0xc0727903 in syscall (frame=0xd600dd38)
> > at /usr/src/sys/i386/i386/trap.c:1034
> > #13 0xc0711630 in Xint0x80_syscall () at /usr/src/sys/i386/i386/exception.s:203
> > ---Type <return> to continue, or q <return> to quit---
> > #14 0x00000033 in ?? ()
> > Looks somewhat strange because nfs_syscalls.c:556 is not in nfssvc(),
> > it's in nfssvc_nfsd().
> > Kernel and world synchronized on 8-CUR though.
> This has been reported a couple of times before but you are the first to
> provide the WITNESS data, which was necessary to proceed. Thanks :)
> So there are two questions:
> 1) Why is Giant being acquired at all? vfs_lookup.c:663 is a
> VFS_LOCK_GIANT indicating that you are doing a lookup on a non-mpsafe
> filesystem. What filesystems are being exported by the server?
> Previously people claimed not to be exporting any filesystems that
> should be marked !mpsafe, which was a puzzle.
I'm sorry for confusing you. :/ Actually 1 msdosfs filesystem is being exported.
BTW panic occurred on UP kernel.
> 2) Missed VFS_UNLOCK_GIANT somewhere, or broken assert. The above trace
> should be enough to diagnose though.
I will try to reproduce and investigate this (in a week).
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