[PATCH AUTOSEL 5.8 48/72] io_uring: fix sq array offset calculation

Sasha Levin
2020-08-08T23:49:53Z

From: Dmitry Vyukov <dvyukov@google.com>

[ 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>
---
fs/io_uring.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 493e5047e67c9..edb5e9d6ae3a4 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7086,6 +7086,9 @@ 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;
@@ -7093,9 +7096,6 @@ 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;
}

--
2.25.1