Re: Re: [PATCH v3 0/3] auth_gss: netns refcount leaks when use-gss-proxy==1

在 2019/8/2 3:53, J. Bruce Fields 写道:

I lost track, what happened to these patches?

--b.

On Wed, Jun 12, 2019 at 08:09:27PM +0800, Wenbin Zeng wrote:

quoted

This patch series fixes an auth_gss bug that results in netns refcount
leaks when use-gss-proxy is set to 1.

The problem was found in privileged docker containers with gssproxy service
enabled and /proc/net/rpc/use-gss-proxy set to 1, the corresponding
struct net->count ends up at 2 after container gets killed, the consequence
is that the struct net cannot be freed.

It turns out that write_gssp() called gssp_rpc_create() to create a rpc
client, this increases net->count by 2; rpcsec_gss_exit_net() is supposed
to decrease net->count but it never gets called because its call-path is:
         net->count==0 -> cleanup_net -> ops_exit_list -> rpcsec_gss_exit_net
Before rpcsec_gss_exit_net() gets called, net->count cannot reach 0, this
is a deadlock situation.

To fix the problem, we must break the deadlock, rpcsec_gss_exit_net()
should move out of the put() path and find another chance to get called,
I think nsfs_evict() is a good place to go, when netns inode gets evicted
we call rpcsec_gss_exit_net() to free the rpc client, this requires a new
callback i.e. evict to be added in struct proc_ns_operations, and add
netns_evict() as one of netns_operations as well.

v1->v2:
  * in nsfs_evict(), move ->evict() in front of ->put()
v2->v3:
  * rpcsec_gss_evict_net() directly call gss_svc_shutdown_net() regardless
    if gssp_clnt is null, this is exactly same to what rpcsec_gss_exit_net()
    previously did

Wenbin Zeng (3):
   nsfs: add evict callback into struct proc_ns_operations
   netns: add netns_evict into netns_operations
   auth_gss: fix deadlock that blocks rpcsec_gss_exit_net when
     use-gss-proxy==1

  fs/nsfs.c                      |  2 ++
  include/linux/proc_ns.h        |  1 +
  include/net/net_namespace.h    |  1 +
  net/core/net_namespace.c       | 12 ++++++++++++
  net/sunrpc/auth_gss/auth_gss.c |  4 ++--
  5 files changed, 18 insertions(+), 2 deletions(-)

-- 
1.8.3.1

These patchsets don't seem to merge into the mainline, are there any 
other patches that fix this bug?