From d0305882825784e74f68a56eee6c3a812a99f235 Mon Sep 17 00:00:00 2001
From: Tony Battersby <tonyb@cybernetics.com>
Date: Tue, 31 Mar 2009 15:24:14 -0700
Subject: [PATCH] epoll: remember the event if epoll_wait returns -EFAULT
If epoll_wait returns -EFAULT, the event that was being returned when the
fault was encountered will be forgotten. This is not a big deal since
EFAULT will happen only if a buggy userspace program passes in a bad
address, in which case what happens later usually doesn't matter.
However, it is easy to remember the event for later, and this patch makes
a simple change to do that.
Signed-off-by: Tony Battersby <tonyb@cybernetics.com>
Acked-by: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/eventpoll.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index db4365f8a75cd..c806a0c4383c4 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1054,8 +1054,10 @@ static int ep_send_events_proc(struct eventpoll *ep, struct list_head *head,
*/
if (revents) {
if (__put_user(revents, &uevent->events) ||
- __put_user(epi->event.data, &uevent->data))
+ __put_user(epi->event.data, &uevent->data)) {
+ list_add(&epi->rdllink, head);
return eventcnt ? eventcnt : -EFAULT;
+ }
eventcnt++;
uevent++;
if (epi->event.events & EPOLLONESHOT)
--
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