| Message ID | 1589409520-1344-1-git-send-email-bfields@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | SUNRPC: 'Directory with parent 'rpc_clnt' already present!' | expand |
On Wed, May 13, 2020 at 06:38:40PM -0400, J. Bruce Fields wrote: > From: "J. Bruce Fields" <bfields@redhat.com> > > Each rpc_client has a cl_clid which is allocated from a global ida, and > a debugfs directory which is named after cl_clid. > > We're releasing the cl_clid before we free the debugfs directory named > after it. As soon as the cl_clid is released, that value is available > for another newly created client. > > That leaves a window where another client may attempt to create a new > debugfs directory with the same name as the not-yet-deleted debugfs > directory from the dying client. Symptoms are log messages like > > Directory 4 with parent 'rpc_clnt' already present! This also cleared up a "file-max limit 199277 reached" warning, which suggests to me a leak in an error path somewhere (I think everything's supposed to work normally even if debugfs file createion fails), but I don't see it. --b. > > Fixes: 7c4310ff5642 "SUNRPC: defer slow parts of rpc_free_client() to a workqueue." > Signed-off-by: J. Bruce Fields <bfields@redhat.com> > --- > net/sunrpc/clnt.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c > index 8350d3a2e9a7..4a7efc00fd83 100644 > --- a/net/sunrpc/clnt.c > +++ b/net/sunrpc/clnt.c > @@ -889,6 +889,7 @@ static void rpc_free_client_work(struct work_struct *work) > * here. > */ > rpc_clnt_debugfs_unregister(clnt); > + rpc_free_clid(clnt); > rpc_clnt_remove_pipedir(clnt); > > kfree(clnt); > @@ -910,7 +911,6 @@ rpc_free_client(struct rpc_clnt *clnt) > xprt_put(rcu_dereference_raw(clnt->cl_xprt)); > xprt_iter_destroy(&clnt->cl_xpi); > put_cred(clnt->cl_cred); > - rpc_free_clid(clnt); > > INIT_WORK(&clnt->cl_work, rpc_free_client_work); > schedule_work(&clnt->cl_work); > -- > 2.26.2
On Wed, May 13, 2020 at 06:40:33PM -0400, J. Bruce Fields wrote: > On Wed, May 13, 2020 at 06:38:40PM -0400, J. Bruce Fields wrote: > > From: "J. Bruce Fields" <bfields@redhat.com> > > > > Each rpc_client has a cl_clid which is allocated from a global ida, and > > a debugfs directory which is named after cl_clid. > > > > We're releasing the cl_clid before we free the debugfs directory named > > after it. As soon as the cl_clid is released, that value is available > > for another newly created client. > > > > That leaves a window where another client may attempt to create a new > > debugfs directory with the same name as the not-yet-deleted debugfs > > directory from the dying client. Symptoms are log messages like > > > > Directory 4 with parent 'rpc_clnt' already present! > > This also cleared up a "file-max limit 199277 reached" warning, which > suggests to me a leak in an error path somewhere (I think everything's > supposed to work normally even if debugfs file createion fails), but I > don't see it. Whoops, I spoke to soon, I'm still seeing that warning, so that's an unrelated issue. --b.
diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index 8350d3a2e9a7..4a7efc00fd83 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -889,6 +889,7 @@ static void rpc_free_client_work(struct work_struct *work) * here. */ rpc_clnt_debugfs_unregister(clnt); + rpc_free_clid(clnt); rpc_clnt_remove_pipedir(clnt); kfree(clnt); @@ -910,7 +911,6 @@ rpc_free_client(struct rpc_clnt *clnt) xprt_put(rcu_dereference_raw(clnt->cl_xprt)); xprt_iter_destroy(&clnt->cl_xpi); put_cred(clnt->cl_cred); - rpc_free_clid(clnt); INIT_WORK(&clnt->cl_work, rpc_free_client_work); schedule_work(&clnt->cl_work);