linux-kernel - [PATCH 5.4 111/191] io_uring: io_allocate_scq

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Date:   Thu,  2 Jan 2020 23:06:33 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        syzbot+0d818c0d39399188f393@...kaller.appspotmail.com,
        Jens Axboe <axboe@...nel.dk>, Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.4 111/191] io_uring: io_allocate_scq_urings() should return a sane state

From: Jens Axboe <axboe@...nel.dk>

[ Upstream commit eb065d301e8c83643367bdb0898becc364046bda ]

We currently rely on the ring destroy on cleaning things up in case of
failure, but io_allocate_scq_urings() can leave things half initialized
if only parts of it fails.

Be nice and return with either everything setup in success, or return an
error with things nicely cleaned up.

Reported-by: syzbot+0d818c0d39399188f393@...kaller.appspotmail.com
Signed-off-by: Jens Axboe <axboe@...nel.dk>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/io_uring.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index a340147387ec..74e786578c77 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3773,12 +3773,18 @@ static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
 	ctx->cq_entries = rings->cq_ring_entries;
 
 	size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
-	if (size == SIZE_MAX)
+	if (size == SIZE_MAX) {
+		io_mem_free(ctx->rings);
+		ctx->rings = NULL;
 		return -EOVERFLOW;
+	}
 
 	ctx->sq_sqes = io_mem_alloc(size);
-	if (!ctx->sq_sqes)
+	if (!ctx->sq_sqes) {
+		io_mem_free(ctx->rings);
+		ctx->rings = NULL;
 		return -ENOMEM;
+	}
 
 	return 0;
 }
-- 
2.20.1