From: Jens Axboe <axboe@kernel.dk>
Date: Wed, 7 Dec 2022 16:23:06 +0000 (-0700)
Subject: eventpoll: ensure we pass back -EBADF for a bad file descriptor
X-Git-Tag: epoll-min_ts-2022-12-08^0
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=refs%2Fheads%2Fepoll-min_ts;p=linux-2.6-block.git

eventpoll: ensure we pass back -EBADF for a bad file descriptor

A previous commit moved file checking earlier in epoll_ctl(), and as a
result, we now have error == -EINVAL going into the test case for
whether or not the passed in target file is valid or not. This should be
-EBADF as per earlier, assign it correctly, otherwise epoll_ctl02 from
LTP correctly identifies this bad return value:

epoll_ctl02.c:87: TFAIL: epoll_clt(...) if fd is an invalid fd expected EBADF: EINVAL (22)

Fixes: 3fe64a3a96d4 ("eventpoll: move file checking earlier for epoll_ctl()")
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
---

diff --git a/fs/eventpoll.c b/fs/eventpoll.c
index ec7ffce8265a..de9c551e1993 100644
--- a/fs/eventpoll.c
+++ b/fs/eventpoll.c
@@ -2195,6 +2195,7 @@ int do_epoll_ctl(int epfd, int op, int fd, struct epoll_event *epds,
 	}
 
 	/* Get the "struct file *" for the target file */
+	error = -EBADF;
 	tf = fdget(fd);
 	if (!tf.file)
 		goto error_fput;