From: Dmitry Vyukov <dvyukov@google.com>
Date: Sat, 11 Jul 2020 09:31:11 +0000 (+0200)
Subject: io_uring: fix sq array offset calculation
X-Git-Tag: v5.4.59~235
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=0b1799662a61a71d6f986a831ba48c8af116a29e;p=users%2Fdwmw2%2Flinux.git

io_uring: fix sq array offset calculation

[ Upstream commit b36200f543ff07a1cb346aa582349141df2c8068 ]

rings_size() sets sq_offset to the total size of the rings (the returned
value which is used for memory allocation). This is wrong: sq array should
be located within the rings, not after them. Set sq_offset to where it
should be.

Fixes: 75b28affdd6a ("io_uring: allocate the two rings together")
Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Hristo Venev <hristo@venev.name>
Cc: io-uring@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/fs/io_uring.c b/fs/io_uring.c
index c1aaee061dae5..0460420250255 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3391,6 +3391,9 @@ static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries,
 		return SIZE_MAX;
 #endif
 
+	if (sq_offset)
+		*sq_offset = off;
+
 	sq_array_size = array_size(sizeof(u32), sq_entries);
 	if (sq_array_size == SIZE_MAX)
 		return SIZE_MAX;
@@ -3398,9 +3401,6 @@ static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries,
 	if (check_add_overflow(off, sq_array_size, &off))
 		return SIZE_MAX;
 
-	if (sq_offset)
-		*sq_offset = off;
-
 	return off;
 }