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From: Tony Battersby <tonyb@cybernetics.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Davide Libenzi <davidel@xmailserver.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [PATCH 2/5] epoll: remember the event if epoll_wait returns -EFAULT
Date: Mon, 02 Mar 2009 18:10:13 -0500	[thread overview]
Message-ID: <49AC6755.6050809@cybernetics.com> (raw)

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>
---
--- a/fs/eventpoll.c	2009-02-23 14:01:41.000000000 -0500
+++ b/fs/eventpoll.c	2009-02-23 14:01:47.000000000 -0500
@@ -1082,8 +1082,10 @@ static int ep_send_events_proc(struct ev
 		 */
 		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)



                 reply	other threads:[~2009-03-02 23:10 UTC|newest]

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