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authorEric Paris <eparis@redhat.com>2009-08-16 21:51:44 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-08-17 16:37:37 -0400
commiteef3a116be11d35396efb2a8cc7345fd3221e294 (patch)
tree2a5d0b36dd5985f29eac43f51b03e610e40b7c9b /fs/notify
parent0f66f96d21b4bbff49baaa337546e687d7c58e87 (diff)
notify: unused event private race
inotify decides if private data it passed to get added to an event was used by checking list_empty(). But it's possible that the event may have been dequeued and the private event removed so it would look empty. The fix is to use the return code from fsnotify_add_notify_event rather than looking at the list. Signed-off-by: Eric Paris <eparis@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/notify')
-rw-r--r--fs/notify/inotify/inotify_fsnotify.c13
-rw-r--r--fs/notify/inotify/inotify_user.c7
-rw-r--r--fs/notify/notification.c7
3 files changed, 13 insertions, 14 deletions
diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c
index 47cd258fd24d..5dcbafe72d71 100644
--- a/fs/notify/inotify/inotify_fsnotify.c
+++ b/fs/notify/inotify/inotify_fsnotify.c
@@ -62,13 +62,14 @@ static int inotify_handle_event(struct fsnotify_group *group, struct fsnotify_ev
62 event_priv->wd = wd; 62 event_priv->wd = wd;
63 63
64 ret = fsnotify_add_notify_event(group, event, fsn_event_priv); 64 ret = fsnotify_add_notify_event(group, event, fsn_event_priv);
65 /* EEXIST is not an error */ 65 if (ret) {
66 if (ret == -EEXIST)
67 ret = 0;
68
69 /* did event_priv get attached? */
70 if (list_empty(&fsn_event_priv->event_list))
71 inotify_free_event_priv(fsn_event_priv); 66 inotify_free_event_priv(fsn_event_priv);
67 /* EEXIST says we tail matched, EOVERFLOW isn't something
68 * to report up the stack. */
69 if ((ret == -EEXIST) ||
70 (ret == -EOVERFLOW))
71 ret = 0;
72 }
72 73
73 /* 74 /*
74 * If we hold the entry until after the event is on the queue 75 * If we hold the entry until after the event is on the queue
diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index f30d9bbc2e1b..c172a7a17b17 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -386,6 +386,7 @@ void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry,
386 struct fsnotify_event *ignored_event; 386 struct fsnotify_event *ignored_event;
387 struct inotify_event_private_data *event_priv; 387 struct inotify_event_private_data *event_priv;
388 struct fsnotify_event_private_data *fsn_event_priv; 388 struct fsnotify_event_private_data *fsn_event_priv;
389 int ret;
389 390
390 ignored_event = fsnotify_create_event(NULL, FS_IN_IGNORED, NULL, 391 ignored_event = fsnotify_create_event(NULL, FS_IN_IGNORED, NULL,
391 FSNOTIFY_EVENT_NONE, NULL, 0, 392 FSNOTIFY_EVENT_NONE, NULL, 0,
@@ -404,10 +405,8 @@ void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry,
404 fsn_event_priv->group = group; 405 fsn_event_priv->group = group;
405 event_priv->wd = ientry->wd; 406 event_priv->wd = ientry->wd;
406 407
407 fsnotify_add_notify_event(group, ignored_event, fsn_event_priv); 408 ret = fsnotify_add_notify_event(group, ignored_event, fsn_event_priv);
408 409 if (ret)
409 /* did the private data get added? */
410 if (list_empty(&fsn_event_priv->event_list))
411 inotify_free_event_priv(fsn_event_priv); 410 inotify_free_event_priv(fsn_event_priv);
412 411
413skip_send_ignore: 412skip_send_ignore:
diff --git a/fs/notify/notification.c b/fs/notify/notification.c
index 521368574e97..74b3cf30bc6b 100644
--- a/fs/notify/notification.c
+++ b/fs/notify/notification.c
@@ -171,9 +171,7 @@ int fsnotify_add_notify_event(struct fsnotify_group *group, struct fsnotify_even
171 struct list_head *list = &group->notification_list; 171 struct list_head *list = &group->notification_list;
172 struct fsnotify_event_holder *last_holder; 172 struct fsnotify_event_holder *last_holder;
173 struct fsnotify_event *last_event; 173 struct fsnotify_event *last_event;
174 174 int ret = 0;
175 /* easy to tell if priv was attached to the event */
176 INIT_LIST_HEAD(&priv->event_list);
177 175
178 /* 176 /*
179 * There is one fsnotify_event_holder embedded inside each fsnotify_event. 177 * There is one fsnotify_event_holder embedded inside each fsnotify_event.
@@ -194,6 +192,7 @@ alloc_holder:
194 192
195 if (group->q_len >= group->max_events) { 193 if (group->q_len >= group->max_events) {
196 event = &q_overflow_event; 194 event = &q_overflow_event;
195 ret = -EOVERFLOW;
197 /* sorry, no private data on the overflow event */ 196 /* sorry, no private data on the overflow event */
198 priv = NULL; 197 priv = NULL;
199 } 198 }
@@ -235,7 +234,7 @@ alloc_holder:
235 mutex_unlock(&group->notification_mutex); 234 mutex_unlock(&group->notification_mutex);
236 235
237 wake_up(&group->notification_waitq); 236 wake_up(&group->notification_waitq);
238 return 0; 237 return ret;
239} 238}
240 239
241/* 240/*