linux-kernel - [PATCH][next] io_uring: ensure variable ret is initialized to zero

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Date:   Thu, 26 Sep 2019 10:50:12 +0100
From:   Colin King <colin.king@...onical.com>
To:     Jens Axboe <axboe@...nel.dk>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        linux-block@...r.kernel.org, linux-fsdevel@...r.kernel.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH][next] io_uring: ensure variable ret is initialized to zero

From: Colin Ian King <colin.king@...onical.com>

In the case where sig is NULL the error variable ret is not initialized
and may contain a garbage value on the final checks to see if ret is
-ERESTARTSYS.  Best to initialize ret to zero before the do loop to
ensure the ret does not accidentially contain -ERESTARTSYS before the
loop.

Addresses-Coverity: ("Uninitialized scalar variable")
Fixes: dd671c79e40b ("io_uring: make CQ ring wakeups be more efficient")
Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 fs/io_uring.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 7b5710e3a18c..aa8ac557493c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2835,6 +2835,7 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
 			return ret;
 	}
 
+	ret = 0;
 	iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts);
 	do {
 		prepare_to_wait_exclusive(&ctx->wait, &iowq.wq,
-- 
2.20.1