From: Al Viro <viro@zeniv.linux.org.uk>
Date: Fri, 25 Sep 2020 23:48:56 +0000 (-0400)
Subject: reverse_path_check_proc(): don't bother with cookies
X-Git-Tag: v5.11-rc1~139^2~18
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=0c320f776ed83e1ebde4d49bc316b23e868b4737;p=thirdparty%2Flinux.git

reverse_path_check_proc(): don't bother with cookies

We know there's no loops by the time we call it; the
only thing we care about is too deep reverse paths.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index 3e6f1f97f246a..0f540e91aa92d 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -1311,7 +1311,7 @@ static int reverse_path_check_proc(struct file *file, int depth)
 	int error = 0;
 	struct epitem *epi;
 
-	if (!ep_push_nested(file)) /* limits recursion */
+	if (depth > EP_MAX_NESTS) /* too deep nesting */
 		return -1;
 
 	/* CTL_DEL can remove links here, but that can't increase our count */
@@ -1336,7 +1336,6 @@ static int reverse_path_check_proc(struct file *file, int depth)
 		}
 	}
 	rcu_read_unlock();
-	nesting--; /* pop */
 	return error;
 }