From: Trond Myklebust trond.myklebust@hammerspace.com
commit 51fd2eb52c0ca8275a906eed81878ef50ae94eb0 upstream.
nfs_idmap_instantiate() will cause the process that is waiting in request_key_with_auxdata() to wake up and exit. If there is a second process waiting for the idmap->idmap_mutex, then it may wake up and start a new call to request_key_with_auxdata(). If the call to idmap_pipe_downcall() from the first process has not yet finished calling nfs_idmap_complete_pipe_upcall_locked(), then we may end up triggering the WARN_ON_ONCE() in nfs_idmap_prepare_pipe_upcall().
The fix is to ensure that we clear idmap->idmap_upcall_data before calling nfs_idmap_instantiate().
Fixes: e9ab41b620e4 ("NFSv4: Clean up the legacy idmapper upcall") Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/nfs/nfs4idmap.c | 46 ++++++++++++++++++++++++---------------------- 1 file changed, 24 insertions(+), 22 deletions(-)
--- a/fs/nfs/nfs4idmap.c +++ b/fs/nfs/nfs4idmap.c @@ -543,22 +543,20 @@ nfs_idmap_prepare_pipe_upcall(struct idm return true; }
-static void -nfs_idmap_complete_pipe_upcall_locked(struct idmap *idmap, int ret) +static void nfs_idmap_complete_pipe_upcall(struct idmap_legacy_upcalldata *data, + int ret) { - struct key *authkey = idmap->idmap_upcall_data->authkey; - - kfree(idmap->idmap_upcall_data); - idmap->idmap_upcall_data = NULL; - complete_request_key(authkey, ret); - key_put(authkey); + complete_request_key(data->authkey, ret); + key_put(data->authkey); + kfree(data); }
-static void -nfs_idmap_abort_pipe_upcall(struct idmap *idmap, int ret) +static void nfs_idmap_abort_pipe_upcall(struct idmap *idmap, + struct idmap_legacy_upcalldata *data, + int ret) { - if (idmap->idmap_upcall_data != NULL) - nfs_idmap_complete_pipe_upcall_locked(idmap, ret); + if (cmpxchg(&idmap->idmap_upcall_data, data, NULL) == data) + nfs_idmap_complete_pipe_upcall(data, ret); }
static int nfs_idmap_legacy_upcall(struct key *authkey, void *aux) @@ -595,7 +593,7 @@ static int nfs_idmap_legacy_upcall(struc
ret = rpc_queue_upcall(idmap->idmap_pipe, msg); if (ret < 0) - nfs_idmap_abort_pipe_upcall(idmap, ret); + nfs_idmap_abort_pipe_upcall(idmap, data, ret);
return ret; out2: @@ -651,6 +649,7 @@ idmap_pipe_downcall(struct file *filp, c struct request_key_auth *rka; struct rpc_inode *rpci = RPC_I(file_inode(filp)); struct idmap *idmap = (struct idmap *)rpci->private; + struct idmap_legacy_upcalldata *data; struct key *authkey; struct idmap_msg im; size_t namelen_in; @@ -660,10 +659,11 @@ idmap_pipe_downcall(struct file *filp, c * will have been woken up and someone else may now have used * idmap_key_cons - so after this point we may no longer touch it. */ - if (idmap->idmap_upcall_data == NULL) + data = xchg(&idmap->idmap_upcall_data, NULL); + if (data == NULL) goto out_noupcall;
- authkey = idmap->idmap_upcall_data->authkey; + authkey = data->authkey; rka = get_request_key_auth(authkey);
if (mlen != sizeof(im)) { @@ -685,18 +685,17 @@ idmap_pipe_downcall(struct file *filp, c if (namelen_in == 0 || namelen_in == IDMAP_NAMESZ) { ret = -EINVAL; goto out; -} + }
- ret = nfs_idmap_read_and_verify_message(&im, - &idmap->idmap_upcall_data->idmap_msg, - rka->target_key, authkey); + ret = nfs_idmap_read_and_verify_message(&im, &data->idmap_msg, + rka->target_key, authkey); if (ret >= 0) { key_set_timeout(rka->target_key, nfs_idmap_cache_timeout); ret = mlen; }
out: - nfs_idmap_complete_pipe_upcall_locked(idmap, ret); + nfs_idmap_complete_pipe_upcall(data, ret); out_noupcall: return ret; } @@ -710,7 +709,7 @@ idmap_pipe_destroy_msg(struct rpc_pipe_m struct idmap *idmap = data->idmap;
if (msg->errno) - nfs_idmap_abort_pipe_upcall(idmap, msg->errno); + nfs_idmap_abort_pipe_upcall(idmap, data, msg->errno); }
static void @@ -718,8 +717,11 @@ idmap_release_pipe(struct inode *inode) { struct rpc_inode *rpci = RPC_I(inode); struct idmap *idmap = (struct idmap *)rpci->private; + struct idmap_legacy_upcalldata *data;
- nfs_idmap_abort_pipe_upcall(idmap, -EPIPE); + data = xchg(&idmap->idmap_upcall_data, NULL); + if (data) + nfs_idmap_complete_pipe_upcall(data, -EPIPE); }
int nfs_map_name_to_uid(const struct nfs_server *server, const char *name, size_t namelen, kuid_t *uid)