panic: mutex Giant owned at nfs_syscalls.c:556
pluknet
pluknet at gmail.com
Mon Mar 3 20:16:26 UTC 2008
On 03/03/2008, Kostik Belousov <kostikbel at gmail.com> wrote:
> On Mon, Mar 03, 2008 at 09:27:15PM +0300, pluknet wrote:
> > On 03/03/2008, Kostik Belousov <kostikbel at gmail.com> wrote:
> > [snip]
> > > To summarize, I need both the tcpdump and kernel/witness messages from
> > > the panic.
> > >
> >
> > I'm sorry. Here it is.
> > http://pluknet.nm.ru/dev/tcpdump-nfsserver-full.raw
> >
> > The messages (same as unread msgbuf in initial posting, hand-scribed):
> > panic: mutex Giant owned at
> > /usr/src/sys/modules/nfsserver/../../nfsserver/nfs_syscalls.c:556
> > KDB: enter: panic
> > [thread pid 601 tid 100055 ]
> > Stopped at kdb_enter+0x3a: movl $0,kdb_why
> > db> show locks
> > exclusive sleep mutex nfsd_mtx r = 0 (0xc2e0af40) 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
> >
> > > Nevertheless, the patch below might help with the panic during
> > > the unlinking (not tested).
> > >
> > > diff --git a/sys/nfsserver/nfs_serv.c b/sys/nfsserver/nfs_serv.c
> > > index 446651d..87e1aaa 100644
> > > --- a/sys/nfsserver/nfs_serv.c
> > > +++ b/sys/nfsserver/nfs_serv.c
> > > @@ -2146,7 +2146,7 @@ nfsrv_remove(struct nfsrv_descript *nfsd, struct nfssvc_sock *slp,
> > > nfsfh_t nfh;
> > > fhandle_t *fhp;
> > > struct mount *mp = NULL;
> > > - int vfslocked;
> > > + int vfslocked, vfslocked1;
> > >
> > > nfsdbprintf(("%s %d\n", __FILE__, __LINE__));
> > > ndclear(&nd);
> > > @@ -2168,7 +2168,11 @@ nfsrv_remove(struct nfsrv_descript *nfsd, struct nfssvc_sock *slp,
> > > nd.ni_cnd.cn_flags = LOCKPARENT | LOCKLEAF | MPSAFE;
> > > error = nfs_namei(&nd, fhp, len, slp, nam, &md, &dpos,
> > > &dirp, v3, &dirfor, &dirfor_ret, td, FALSE);
> > > - vfslocked = NDHASGIANT(&nd);
> > > + vfslocked1 = NDHASGIANT(&nd);
> > > + if (vfslocked && vfslocked1)
> > > + VFS_UNLOCK_GIANT(vfslocked1);
> > > + if (vfslocked || vfslocked1)
> > > + vfslocked = 1;
> > > if (dirp && !v3) {
> > > vrele(dirp);
> > > dirp = NULL;
> > >
> > >
> >
> > Now the last lock triplex looks like:
> > vfslocked lock in
> > /usr/src/sys/modules/nfsserver/../../nfsserver/nfs_serv.c, 2161
> > vfslocked lock in
> > /usr/src/sys/modules/nfsserver/../../nfsserver/nfs_srvsubs.c, 1106
> > vfslocked lock in
> > /usr/src/sys/modules/nfsserver/../../nfsserver/nfs_srvsubs.c, 673
> > vfslocked unlock in
> > /usr/src/sys/modules/nfsserver/../../nfsserver/nfs_srvsubs.c, 916
> > vfslocked1 unlock in
> > /usr/src/sys/modules/nfsserver/../../nfsserver/nfs_serv.c, 2173
> > ^^^
> > vfslocked unlock in
> > /usr/src/sys/modules/nfsserver/../../nfsserver/nfs_serv.c, 2238
> >
> > And no panic. Thanks.
>
>
> Could you, please, clarify. As I read you mail, the patch fixed at least
> one of your panic. Are there any other situations where nfs server over
> non-MPSAFE fs panics for you ? It is possible that what you reported
> before actually contains several different reasons for Giant leak.
Of course.
That another situation is while performing /etc/rc.d/nfsd stop
> System call nfssvc returning with the following locks held:
> exclusive sleep mutex Giant r = 2 (0xc07e6410) locked @
> /usr/src/sys/modules/nfsserver/../../nfsserver/nfs_srvsubs.c:1106
> panic: witness_warn
I got no panic with this patch:
# /etc/rc.d/nfsd stop
Stopping nfsd.
kill: 1737: No such process
kill: 1738: No such process
kill: 1739: No such process
kill: 1740: No such process
#
wbr,
pluknet
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