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epoll: remember the event if epoll_wait returns -EFAULT

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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>
This commit is contained in:
Tony Battersby 2009-03-31 15:24:14 -07:00 committed by Linus Torvalds
parent abff55cee1
commit d030588282
1 changed files with 3 additions and 1 deletions
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4
fs/eventpoll.c
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@ -1054,8 +1054,10 @@ static int ep_send_events_proc(struct eventpoll *ep, struct list_head *head,
*/ */
if (revents) { if (revents) {
if (__put_user(revents, &uevent->events) || 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; return eventcnt ? eventcnt : -EFAULT;
}
eventcnt++; eventcnt++;
uevent++; uevent++;
if (epi->event.events & EPOLLONESHOT) if (epi->event.events & EPOLLONESHOT)