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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, Andres Freund <andres@anarazel.de>,
        Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 5.4 033/104] Revert "io_uring: only allow submit from owning task"
Date:   Tue, 28 Jan 2020 14:59:54 +0100
Message-Id: <20200128135821.839050866@linuxfoundation.org>
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From: Jens Axboe <axboe@kernel.dk>

commit 73e08e711d9c1d79fae01daed4b0e1fee5f8a275 upstream.

This ends up being too restrictive for tasks that willingly fork and
share the ring between forks. Andres reports that this breaks his
postgresql work. Since we're close to 5.5 release, revert this change
for now.

Cc: stable@vger.kernel.org
Fixes: 44d282796f81 ("io_uring: only allow submit from owning task")
Reported-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/io_uring.c |    6 ------
 1 file changed, 6 deletions(-)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3716,12 +3716,6 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned
 			wake_up(&ctx->sqo_wait);
 		submitted = to_submit;
 	} else if (to_submit) {
-		if (current->mm != ctx->sqo_mm ||
-		    current_cred() != ctx->creds) {
-			ret = -EPERM;
-			goto out;
-		}
-
 		to_submit = min(to_submit, ctx->sq_entries);
 
 		mutex_lock(&ctx->uring_lock);