From: Andrew Morton <akpm@linux-foundation.org>
To: Sasha Levin <sasha.levin@oracle.com>
Cc: john@johnmccutchan.com, rlove@rlove.org, eparis@parisplace.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] fsnotify: don't put user context if it was never assigned
Date: Thu, 11 Sep 2014 13:43:55 -0700 [thread overview]
Message-ID: <20140911134355.21bed9dbf5a0c7a8190c748f@linux-foundation.org> (raw)
In-Reply-To: <1406640314-25201-1-git-send-email-sasha.levin@oracle.com>
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)
next prev parent reply other threads:[~2014-09-11 20:43 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-29 13:25 [PATCH] fsnotify: don't put user context if it was never assigned Sasha Levin
2014-09-03 21:31 ` Sasha Levin
2014-09-08 14:24 ` Sasha Levin
2014-09-11 17:52 ` Heinrich Schuchardt
2014-09-12 16:20 ` Jan Kara
2014-09-11 20:43 ` Andrew Morton [this message]
2014-09-12 1:49 ` Sasha Levin
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