2007-09-19 Martin Hunt <hunt@redhat.com>

	PR 5042
	* procfs.c (_stp_rmdir_proc_module): Warn if removal of
	/proc/systemtap/module is deferred. Do not defer removal of
	/proc/systemtap.
	(_stp_mkdir_proc_module): Call path_release(). Set ownership of
	/proc/systemtap/module to force deletion to be deferred.
	(_stp_create_procfs): Set owner of all path components.

diff --git a/runtime/ChangeLog b/runtime/ChangeLog
index 9a2ee276c772e5ac07dfa3bac0f879655f86e904..6d4396571e77ba5ac2cedec6ee17c44899211121 100644 (file)
--- a/runtime/ChangeLog
+++ b/runtime/ChangeLog
@@ -1,3 +1,12 @@
+2007-09-19  Martin Hunt  <hunt@redhat.com>
+       PR 5042
+       * procfs.c (_stp_rmdir_proc_module): Warn if removal of
+       /proc/systemtap/module is deferred. Do not defer removal of
+       /proc/systemtap.
+       (_stp_mkdir_proc_module): Call path_release(). Set ownership of
+       /proc/systemtap/module to force deletion to be deferred.
+       (_stp_create_procfs): Set owner of all path components.
+
 2007-09-14  Martin Hunt  <hunt@redhat.com>
 
        * procfs.c (_stp_create_procfs): Be sure that directories in the path

diff --git a/runtime/procfs.c b/runtime/procfs.c
index 9e028d78e6b858b97f859c9e7f736a215ccaba73..eb0f845ce20a6eed75fac1ffcc1545a24ce939a8 100644 (file)
--- a/runtime/procfs.c
+++ b/runtime/procfs.c
@@ -30,6 +30,9 @@ void _stp_close_procfs(void);
 void _stp_rmdir_proc_module(void)
 {
         if (_stp_proc_root && _stp_proc_root->subdir == NULL) {
+               if (atomic_read(&_stp_proc_root->count))
+                       _stp_warn("Removal of /proc/systemtap/%s\nis deferred until it is no longer in use.\n"
+                                 "Systemtap module removal will block.\n", THIS_MODULE->name); 
                remove_proc_entry(THIS_MODULE->name, _stp_proc_stap);
                _stp_proc_root = NULL;
        }
@@ -40,7 +43,14 @@ void _stp_rmdir_proc_module(void)
                        return;
                }
 
-               if (_stp_proc_stap->subdir == NULL) {
+               /* Important! Do not attempt removal of /proc/systemtap */
+               /* if in use.  This will put the PDE in deleted state */
+               /* pending usage count dropping to 0. During this time, */
+               /* path_lookup() will still find it and allow new */
+               /* modules to use it, even though it will not show up */
+               /* in directory listings. */
+
+               if (atomic_read(&_stp_proc_stap->count) == 0) {
                        remove_proc_entry("systemtap", NULL);
                        _stp_proc_stap = NULL;
                }
@@ -76,10 +86,15 @@ int _stp_mkdir_proc_module(void)
                                _stp_unlock_debugfs();
                                goto done;
                        }
-               } else
+               } else {
                        _stp_proc_stap = PDE(nd.dentry->d_inode);
-
+                       path_release (&nd);
+               }
+               
                _stp_proc_root = proc_mkdir(THIS_MODULE->name, _stp_proc_stap);
+               if (_stp_proc_root != NULL)
+                       _stp_proc_root->owner = THIS_MODULE;
+
                _stp_unlock_debugfs();
        }
 done:
@@ -133,6 +148,7 @@ int _stp_create_procfs(const char *path, int num)
                                    goto err;
                            }
                            _stp_pde[_stp_num_pde++] = last_dir;
+                           last_dir->owner = THIS_MODULE;
                            last_dir->uid = _stp_uid;
                            last_dir->gid = _stp_gid;
                } else {