Re: linux-next: build failure after merge of the nfsd tree

From: Chuck Lever
Date: Mon Apr 29 2013 - 13:47:58 EST

On Apr 29, 2013, at 1:38 PM, "J. Bruce Fields" <bfields@xxxxxxxxxxxx> wrote:

> On Mon, Apr 29, 2013 at 01:04:01PM -0400, Chuck Lever wrote:
>> On Apr 29, 2013, at 12:21 PM, Trond Myklebust
>> <trond.myklebust@xxxxxxxxxx> wrote:
>>> On Mon, 2013-04-29 at 12:05 -0400, Chuck Lever wrote:
>>>> On Apr 29, 2013, at 11:45 AM, "J. Bruce Fields"
>>>> <bfields@xxxxxxxxxxxx> wrote:
>>>>> On Mon, Apr 29, 2013 at 10:53:37AM -0400, Chuck Lever wrote:
>>>>>> On Apr 28, 2013, at 9:24 PM, Stephen Rothwell
>>>>>> <sfr@xxxxxxxxxxxxxxxx> wrote:
>>>>>>> Hi J.,
>>>>>>> After merging the nfsd tree, today's linux-next build (powerpc
>>>>>>> ppc64_defconfig) failed like this:
>>>>>>> net/sunrpc/auth_gss/svcauth_gss.c: In function
>>>>>>> 'gss_proxy_save_rsc': net/sunrpc/auth_gss/svcauth_gss.c:1182:3:
>>>>>>> error: implicit declaration of function 'gss_mech_get_by_OID'
>>>>>>> [-Werror=implicit-function-declaration]
>>>>>>> Caused byc ommit 030d794bf498 ("SUNRPC: Use gssproxy upcall for
>>>>>>> server RPCGSS authentication"). gss_mech_get_by_OID() made
>>>>>>> static to net/sunrpc/auth_gss/gss_mech_switch.c by commit
>>>>>>> 9568c5e9a61d ("SUNRPC: Introduce rpcauth_get_pseudoflavor()") in
>>>>>>> the nfs tree (part of the nfs tree that you did not merge).
>>>>>>> I don't know how to fix this, so I have used the nfsd tree from
>>>>>>> next-20130426 for today.
>>>>>> Bruce, it might make sense for me to submit the three server-side
>>>>>> RPC GSS patches, and then you can rebase the gssproxy work on top
>>>>>> of those. Let me know how you would like to proceed.
>>>>> I'm happy to take those patches whenever you consider them ready.
>>>>> Would that fix the problem?
>>>> Someone would need to modify the gssproxy patches to use the new
>>>> interfaces.
>>>>> Also: it looks like 030d794bf498 "SUNRPC: Introduce
>>>>> rpcauth_get_pseudoflavor()" is in Trond's linux-next, but not his
>>>>> nfs-for-next. I'm not sure what that means--is it safe to rebase
>>>>> on top of *that*?
>>>> That doesn't seem right to me.
>>> I've now pulled the rpcsec_gss changes into the nfs-for-next. The
>>> main reason why they were not pulled in earlier was due to
>>> uncertainty what to do about the increase in "AUTH_GSS upcall timed
>>> out." syslog warnings.
>> Trond's nfs-for-next now has the new rpcauth_get_gssinfo() and
>> rpcauth_get_pseudoflavor() APIs, which are replacements for direct
>> calls into the GSS mech switch. These APIs are a little more generic,
>> and more robust in the face of unloaded GSS kernel modules.
>> Instead of gss_mech_get_by_OID(), I suspect you want
>> rpcauth_get_pseudoflavor(), but I haven't looked at the gssproxy code.
> It's doing
> status = -EOPNOTSUPP;
> gm = gss_mech_get_by_OID(&ud->mech_oid);
> if (!gm)
> goto out;
> status = -EINVAL;
> status = gss_import_sec_context(ud->,
> ud->out_handle.len,
> gm, &rsci.mechctx,
> &expiry, GFP_KERNEL);
> if (status)
> goto out;
> So we need a way to get from an OID and some mechanism-specific data to
> a context.
> Looks to me like we just want to re-export gss_mech_get_by_OID().

The reason for the new wrappers is to load the kernel modules properly before trying to discover the OID -> mechanism mapping.

Where are you calling it from? If it's from outside of the GSS module, how do you guarantee the rpc_gss_auth module is loaded? What if the GSS mechanism for that OID isn't loaded?

Chuck Lever

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