On 2017-11-05 19:02, Trond Myklebust wrote: > On Sun, 2017-11-05 at 13:00 +0300, Vasily Averin wrote: >> Be sure that nfs_client_list and nfs_volume_list lists initialized >> in net_init hook were return to initial state in net_exit hook. >> >> Signed-off-by: Vasily Averin <v...@virtuozzo.com> >> --- >> fs/nfs/client.c | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/fs/nfs/client.c b/fs/nfs/client.c >> index 22880ef..7c0691c 100644 >> --- a/fs/nfs/client.c >> +++ b/fs/nfs/client.c >> @@ -204,6 +204,10 @@ void nfs_cleanup_cb_ident_idr(struct net *net) >> struct nfs_net *nn = net_generic(net, nfs_net_id); >> >> idr_destroy(&nn->cb_ident_idr); >> + WARN(!list_empty(&nn->nfs_client_list), >> + "net %p exit: nfs_client_list is not empty\n", net); >> + WARN(!list_empty(&nn->nfs_volume_list), >> + "net %p exit: nfs_volume_list is not empty\n", net); >> } >> > > Why do we need these? Is there a specific bug that you are trying to > track down?
I hope such checks allows to detect leaked per-netns objects. Also I hope that all new pernet_operations will inherit such checks too. I assume that elements added into per-net lists should not live longer than net namespace, and should be deleted from the list. I think exit_net hook is good place for such check. Recently I've found lost list_entry and enabled timer on stop of net namespace. Then I've reviewed all existing pernet_operations and found that many drivers have such checks already. So I decided to complete this task and add such checks into all affected subsystems.
