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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 5.4 112/232] io_uring: remove bogus RLIMIT_NOFILE check in file registration
Date:   Thu, 16 Apr 2020 15:23:26 +0200
Message-Id: <20200416131329.139822140@linuxfoundation.org>
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From: Jens Axboe <axboe@kernel.dk>

commit c336e992cb1cb1db9ee608dfb30342ae781057ab upstream.

We already checked this limit when the file was opened, and we keep it
open in the file table. Hence when we added unit_inflight to the count
we want to register, we're doubly accounting these files. This results
in -EMFILE for file registration, if we're at half the limit.

Cc: stable@vger.kernel.org # v5.1+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/io_uring.c |    7 -------
 1 file changed, 7 deletions(-)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3092,13 +3092,6 @@ static int __io_sqe_files_scm(struct io_
 	struct sk_buff *skb;
 	int i;
 
-	if (!capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) {
-		unsigned long inflight = ctx->user->unix_inflight + nr;
-
-		if (inflight > task_rlimit(current, RLIMIT_NOFILE))
-			return -EMFILE;
-	}
-
 	fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
 	if (!fpl)
 		return -ENOMEM;