Re: Regression, bisected: sqlite locking failure on nfs

[Trond Myklebust <Trond.Myklebust@netapp.com>]

On Mon, 2010-11-01 at 15:45 -0400, Chuck Lever wrote:
> On Nov 1, 2010, at 3:42 PM, Trond Myklebust wrote:
> 
> > On Mon, 2010-11-01 at 15:22 -0400, Trond Myklebust wrote:
> >> I suspect nlmclnt_lookup_host() is to blame. It appears to be the _only_
> >> thing in the kernel that actually sets this 'srcaddr' field, and it sets
> >> it to
> >> 
> >> const struct sockaddr source = {
> >> 	.sa_family      = AF_UNSPEC,
> >> };
> >> 
> >> You triggered the bug by removing the line
> >> 
> >> 	transport->srcaddr.ss_family = family;
> >> 
> >> from xs_create_sock().
> >> 
> >>   Trond
> > 
> > Does this fix the regression?
> > 
> > Trond
> > 
> > ----------------------------------------------------------------------------------------------
> > NLM: Fix a regression in lockd
> > 
> > From: Trond Myklebust <Trond.Myklebust@netapp.com>
> > 
> > Nick Bowler reports:
> > There are no unusual messages on the client... but I just logged into
> > the server and I see lots of messages of the following form:
> > 
> >  nfsd: request from insecure port (192.168.8.199:35766)!
> >  nfsd: request from insecure port (192.168.8.199:35766)!
> >  nfsd: request from insecure port (192.168.8.199:35766)!
> >  nfsd: request from insecure port (192.168.8.199:35766)!
> >  nfsd: request from insecure port (192.168.8.199:35766)!
> > 
> > Bisected to commit 9247685088398cf21bcb513bd2832b4cd42516c4 (SUNRPC:
> > Properly initialize sock_xprt.srcaddr in all cases)
> > 
> > Apparently, removing the 'transport->srcaddr.ss_family = family' from
> > xs_create_sock() triggers this due to nlmclnt_lookup_host() incorrectly
> > initialising the srcaddr family to AF_UNSPEC.
> > 
> > Reported-by: Nick Bowler <nbowler@elliptictech.com>
> > Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
> > ---
> > 
> > fs/lockd/host.c |    5 -----
> > 1 files changed, 0 insertions(+), 5 deletions(-)
> > 
> > 
> > diff --git a/fs/lockd/host.c b/fs/lockd/host.c
> > index 25e21e4..9ff0c0e 100644
> > --- a/fs/lockd/host.c
> > +++ b/fs/lockd/host.c
> > @@ -238,9 +238,6 @@ struct nlm_host *nlmclnt_lookup_host(const struct sockaddr *sap,
> > 				     const char *hostname,
> > 				     int noresvport)
> > {
> > -	const struct sockaddr source = {
> > -		.sa_family	= AF_UNSPEC,
> > -	};
> > 	struct nlm_lookup_host_info ni = {
> > 		.server		= 0,
> > 		.sap		= sap,
> > @@ -249,8 +246,6 @@ struct nlm_host *nlmclnt_lookup_host(const struct sockaddr *sap,
> > 		.version	= version,
> > 		.hostname	= hostname,
> > 		.hostname_len	= strlen(hostname),
> > -		.src_sap	= &source,
> > -		.src_len	= sizeof(source),
> > 		.noresvport	= noresvport,
> > 	};
> > 
> > 
> 
> 
> What about that memcpy() in nlm_lookup_host()?  With this patch, wouldn't it be copying garbage into the host's srcaddr field?
> 

It shouldn't. ni->src_len is now zero.

Trond