From: Jason Baron <jbaron@redhat.com>
Date: Wed, 25 Apr 2012 23:01:47 +0000 (-0700)
Subject: epoll: clear the tfile_check_list on -ELOOP
X-Git-Tag: v3.2.24~86
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=11a5b0b59b9b38e71fa45bd9739a6f4ffa8ce61a;p=karo-tx-linux.git

epoll: clear the tfile_check_list on -ELOOP

commit 13d518074a952d33d47c428419693f63389547e9 upstream.

An epoll_ctl(,EPOLL_CTL_ADD,,) operation can return '-ELOOP' to prevent
circular epoll dependencies from being created.  However, in that case we
do not properly clear the 'tfile_check_list'.  Thus, add a call to
clear_tfile_check_list() for the -ELOOP case.

Signed-off-by: Jason Baron <jbaron@redhat.com>
Reported-by: Yurij M. Plotnikov <Yurij.Plotnikov@oktetlabs.ru>
Cc: Nelson Elhage <nelhage@nelhage.com>
Cc: Davide Libenzi <davidel@xmailserver.org>
Tested-by: Alexandra N. Kossovsky <Alexandra.Kossovsky@oktetlabs.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 4d9d3a45e356..a6f376323c7c 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1629,8 +1629,10 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd,
 	if (op == EPOLL_CTL_ADD) {
 		if (is_file_epoll(tfile)) {
 			error = -ELOOP;
-			if (ep_loop_check(ep, tfile) != 0)
+			if (ep_loop_check(ep, tfile) != 0) {
+				clear_tfile_check_list();
 				goto error_tgt_fput;
+			}
 		} else
 			list_add(&tfile->f_tfile_llink, &tfile_check_list);
 	}