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Date: Sun, 16 Aug 2009 21:51:44 -0400 From: Eric Paris <eparis@...hat.com> To: linux-kernel@...r.kernel.org, fs-devel@...r.kernel.org Cc: torvalds@...ux-foundation.org, viro@...IV.linux.org.uk Subject: [PATCH 1/3] 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@...hat.com> --- fs/notify/inotify/inotify_fsnotify.c | 13 +++++++------ fs/notify/inotify/inotify_user.c | 7 +++---- fs/notify/notification.c | 7 +++---- 3 files changed, 13 insertions(+), 14 deletions(-) diff --git a/fs/notify/inotify/inotify_fsnotify.c b/fs/notify/inotify/inotify_fsnotify.c index 47cd258..5dcbafe 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 event_priv->wd = wd; ret = fsnotify_add_notify_event(group, event, fsn_event_priv); - /* EEXIST is not an error */ - if (ret == -EEXIST) - ret = 0; - - /* did event_priv get attached? */ - if (list_empty(&fsn_event_priv->event_list)) + if (ret) { inotify_free_event_priv(fsn_event_priv); + /* EEXIST says we tail matched, EOVERFLOW isn't something + * to report up the stack. */ + if ((ret == -EEXIST) || + (ret == -EOVERFLOW)) + ret = 0; + } /* * 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 c17d5a3..54cbded 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, struct fsnotify_event *ignored_event; struct inotify_event_private_data *event_priv; struct fsnotify_event_private_data *fsn_event_priv; + int ret; ignored_event = fsnotify_create_event(NULL, FS_IN_IGNORED, NULL, FSNOTIFY_EVENT_NONE, NULL, 0, @@ -404,10 +405,8 @@ void inotify_ignored_and_remove_idr(struct fsnotify_mark_entry *entry, fsn_event_priv->group = group; event_priv->wd = ientry->wd; - fsnotify_add_notify_event(group, ignored_event, fsn_event_priv); - - /* did the private data get added? */ - if (list_empty(&fsn_event_priv->event_list)) + ret = fsnotify_add_notify_event(group, ignored_event, fsn_event_priv); + if (ret) inotify_free_event_priv(fsn_event_priv); skip_send_ignore: diff --git a/fs/notify/notification.c b/fs/notify/notification.c index 5213685..74b3cf3 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 struct list_head *list = &group->notification_list; struct fsnotify_event_holder *last_holder; struct fsnotify_event *last_event; - - /* easy to tell if priv was attached to the event */ - INIT_LIST_HEAD(&priv->event_list); + int ret = 0; /* * There is one fsnotify_event_holder embedded inside each fsnotify_event. @@ -194,6 +192,7 @@ alloc_holder: if (group->q_len >= group->max_events) { event = &q_overflow_event; + ret = -EOVERFLOW; /* sorry, no private data on the overflow event */ priv = NULL; } @@ -235,7 +234,7 @@ alloc_holder: mutex_unlock(&group->notification_mutex); wake_up(&group->notification_waitq); - return 0; + return ret; } /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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