Re: [PATCH] auth_gss: unregister gss_domain when unloading module

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

On Sun, 2006-10-29 at 03:55 +0900, Akinobu Mita wrote:
> Reloading rpcsec_gss_krb5 or rpcsec_gss_spkm3 hit duplicate
> registration in svcauth_gss_register_pseudoflavor().
> (If DEBUG_PAGEALLOC is enabled, oops will happen at
> auth_domain_put() --> hlist_del() with uninitialized hlist_node)
> 
> svcauth_gss_register_pseudoflavor(u32 pseudoflavor, char * name)
> {
> 	...
> 
>         test = auth_domain_lookup(name, &new->h);
>         if (test != &new->h) { /* XXX Duplicate registration? */
>                 auth_domain_put(&new->h);
>                 /* dangling ref-count... */
> 	...
> }
> 
> This patch unregisters gss_domain and free it when unloading
> modules (rpcsec_gss_krb5 or rpcsec_gss_spkm3 module call
> gss_mech_unregister())
> 
> Cc: Andy Adamson <andros@citi.umich.edu>
> Cc: "J. Bruce Fields" <bfields@citi.umich.edu>
> Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
> 
>  net/sunrpc/auth_gss/gss_mech_switch.c |    4 ++++
>  net/sunrpc/auth_gss/svcauth_gss.c     |    6 +++---
>  2 files changed, 7 insertions(+), 3 deletions(-)
> 
> Index: work-fault-inject/net/sunrpc/auth_gss/gss_mech_switch.c
> ===================================================================
> --- work-fault-inject.orig/net/sunrpc/auth_gss/gss_mech_switch.c
> +++ work-fault-inject/net/sunrpc/auth_gss/gss_mech_switch.c
> @@ -59,7 +59,11 @@ gss_mech_free(struct gss_api_mech *gm)
>  	int i;
>  
>  	for (i = 0; i < gm->gm_pf_num; i++) {
> +		struct auth_domain *dom;
> +
>  		pf = &gm->gm_pfs[i];
> +		dom = auth_domain_find(pf->auth_domain_name);
> +		auth_domain_put(dom);

Since auth_domain_find() takes a reference on "dom", and
auth_domain_put() releases it, won't this just be a no-op?

>  		kfree(pf->auth_domain_name);
>  		pf->auth_domain_name = NULL;
>  	}
> Index: work-fault-inject/net/sunrpc/auth_gss/svcauth_gss.c
> ===================================================================
> --- work-fault-inject.orig/net/sunrpc/auth_gss/svcauth_gss.c
> +++ work-fault-inject/net/sunrpc/auth_gss/svcauth_gss.c
> @@ -765,9 +765,9 @@ svcauth_gss_register_pseudoflavor(u32 ps
>  
>  	test = auth_domain_lookup(name, &new->h);
>  	if (test != &new->h) { /* XXX Duplicate registration? */
> -		auth_domain_put(&new->h);
> -		/* dangling ref-count... */
> -		goto out;
> +		WARN_ON(1);
> +		kfree(new->h.name);
> +		goto out_free_dom;
>  	}
>  	return 0;
>  

Cheers,
  Trond