linux-kernel - [PATCH] block: do not leak memory in bio_copy_user

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Date:   Wed, 10 Apr 2019 16:27:51 -0400
From:   jglisse@...hat.com
To:     linux-kernel@...r.kernel.org
Cc:     Jérôme Glisse <jglisse@...hat.com>,
        Jens Axboe <axboe@...nel.dk>, linux-block@...r.kernel.org,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        stable@...r.kernel.org
Subject: [PATCH] block: do not leak memory in bio_copy_user_iov()

From: Jérôme Glisse <jglisse@...hat.com>

When bio_add_pc_page() fails in bio_copy_user_iov() we should free
the page we just allocated otherwise we are leaking it.

Signed-off-by: Jérôme Glisse <jglisse@...hat.com>
Cc: Jens Axboe <axboe@...nel.dk>
Cc: linux-block@...r.kernel.org
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: stable@...r.kernel.org
---
 block/bio.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/block/bio.c b/block/bio.c
index b64cedc7f87c..716510ecd7ff 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1298,8 +1298,11 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
 			}
 		}
 
-		if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
+		if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes) {
+			if (!map_data)
+				__free_page(page);
 			break;
+		}
 
 		len -= bytes;
 		offset = 0;
-- 
2.20.1