Messages in this thread | | | Date | Thu, 11 Sep 2014 13:43:55 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] fsnotify: don't put user context if it was never assigned |
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On Tue, 29 Jul 2014 09:25:14 -0400 Sasha Levin <sasha.levin@oracle.com> wrote:
> On some failure paths we may attempt to free user context even > if it wasn't assigned yet. This will cause a NULL ptr deref > and a kernel BUG.
Are you able to identify "some failure paths"? I spent some time grepping, but it's a pain.
Please try to include such info in changelogs because reviewers (ie, me) might want to review those callers to decide whether the bug lies elsewhere.
> --- a/fs/notify/inotify/inotify_fsnotify.c > +++ b/fs/notify/inotify/inotify_fsnotify.c > @@ -165,8 +165,10 @@ static void inotify_free_group_priv(struct fsnotify_group *group) > /* ideally the idr is empty and we won't hit the BUG in the callback */ > idr_for_each(&group->inotify_data.idr, idr_callback, group); > idr_destroy(&group->inotify_data.idr); > - atomic_dec(&group->inotify_data.user->inotify_devs); > - free_uid(group->inotify_data.user); > + if (group->inotify_data.user) { > + atomic_dec(&group->inotify_data.user->inotify_devs); > + free_uid(group->inotify_data.user); > + } > } > > static void inotify_free_event(struct fsnotify_event *fsn_event)
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