Merge tag 'driver-core-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core updates from Greg KH:
 "Here is the "small" driver core patches for 4.11-rc1.

  Not much here, some firmware documentation and self-test updates, a
  debugfs code formatting issue, and a new feature for call_usermodehelper
  to make it more robust on systems that want to lock it down in a more
  secure way.

  All of these have been linux-next for a while now with no reported
  issues"

* tag 'driver-core-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  kernfs: handle null pointers while printing node name and path
  Introduce STATIC_USERMODEHELPER to mediate call_usermodehelper()
  Make static usermode helper binaries constant
  kmod: make usermodehelper path a const string
  firmware: revamp firmware documentation
  selftests: firmware: send expected errors to /dev/null
  selftests: firmware: only modprobe if driver is missing
  platform: Print the resource range if device failed to claim
  kref: prefer atomic_inc_not_zero to atomic_add_unless
  debugfs: improve formatting of debugfs_real_fops()

2 files changed, 14 insertions, 2 deletions

diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index cf4c636ff4da..439b946c4808 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -41,6 +41,9 @@ static bool kernfs_lockdep(struct kernfs_node *kn)
 
 static int kernfs_name_locked(struct kernfs_node *kn, char *buf, size_t buflen)
 {
+	if (!kn)
+		return strlcpy(buf, "(null)", buflen);
+
 	return strlcpy(buf, kn->parent ? kn->name : "/", buflen);
 }
 
@@ -110,6 +113,8 @@ static struct kernfs_node *kernfs_common_ancestor(struct kernfs_node *a,
  * kn_to:   /n1/n2/n3         [depth=3]
  * result:  /../..
  *
+ * [3] when @kn_to is NULL result will be "(null)"
+ *
  * Returns the length of the full path.  If the full length is equal to or
  * greater than @buflen, @buf contains the truncated path with the trailing
  * '\0'.  On error, -errno is returned.
@@ -123,6 +128,9 @@ static int kernfs_path_from_node_locked(struct kernfs_node *kn_to,
 	size_t depth_from, depth_to, len = 0;
 	int i, j;
 
+	if (!kn_to)
+		return strlcpy(buf, "(null)", buflen);
+
 	if (!kn_from)
 		kn_from = kernfs_root(kn_to)->kn;
 
@@ -166,6 +174,8 @@ static int kernfs_path_from_node_locked(struct kernfs_node *kn_to,
  * similar to strlcpy().  It returns the length of @kn's name and if @buf
  * isn't long enough, it's filled upto @buflen-1 and nul terminated.
  *
+ * Fills buffer with "(null)" if @kn is NULL.
+ *
  * This function can be called from any context.
  */
 int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
diff --git a/fs/nfsd/nfs4layouts.c b/fs/nfsd/nfs4layouts.c
index 1fc07a9c70e9..e122da696f1b 100644
--- a/fs/nfsd/nfs4layouts.c
+++ b/fs/nfsd/nfs4layouts.c
@@ -614,6 +614,7 @@ nfsd4_cb_layout_fail(struct nfs4_layout_stateid *ls)
 {
 	struct nfs4_client *clp = ls->ls_stid.sc_client;
 	char addr_str[INET6_ADDRSTRLEN];
+	static char const nfsd_recall_failed[] = "/sbin/nfsd-recall-failed";
 	static char *envp[] = {
 		"HOME=/",
 		"TERM=linux",
@@ -629,12 +630,13 @@ nfsd4_cb_layout_fail(struct nfs4_layout_stateid *ls)
 		"nfsd: client %s failed to respond to layout recall. "
 		"  Fencing..\n", addr_str);
 
-	argv[0] = "/sbin/nfsd-recall-failed";
+	argv[0] = (char *)nfsd_recall_failed;
 	argv[1] = addr_str;
 	argv[2] = ls->ls_file->f_path.mnt->mnt_sb->s_id;
 	argv[3] = NULL;
 
-	error = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
+	error = call_usermodehelper(nfsd_recall_failed, argv, envp,
+				    UMH_WAIT_PROC);
 	if (error) {
 		printk(KERN_ERR "nfsd: fence failed for client %s: %d!\n",
 			addr_str, error);