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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Jeroen de Borst <jeroendb@google.com>,
        Catherine Sullivan <csully@google.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.4 16/46] gve: Fix the queue page list allocated pages count
Date:   Tue,  3 Dec 2019 23:35:36 +0100
Message-Id: <20191203212733.526080403@linuxfoundation.org>
In-Reply-To: <20191203212705.175425505@linuxfoundation.org>
References: <20191203212705.175425505@linuxfoundation.org>
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From: Jeroen de Borst <jeroendb@google.com>

[ Upstream commit a95069ecb7092d03b2ea1c39ee04514fe9627540 ]

In gve_alloc_queue_page_list(), when a page allocation fails,
qpl->num_entries will be wrong.  In this case priv->num_registered_pages
can underflow in gve_free_queue_page_list(), causing subsequent calls
to gve_alloc_queue_page_list() to fail.

Fixes: f5cedc84a30d ("gve: Add transmit and receive support")
Signed-off-by: Jeroen de Borst <jeroendb@google.com>
Reviewed-by: Catherine Sullivan <csully@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/google/gve/gve_main.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/net/ethernet/google/gve/gve_main.c
+++ b/drivers/net/ethernet/google/gve/gve_main.c
@@ -544,7 +544,7 @@ static int gve_alloc_queue_page_list(str
 	}
 
 	qpl->id = id;
-	qpl->num_entries = pages;
+	qpl->num_entries = 0;
 	qpl->pages = kvzalloc(pages * sizeof(*qpl->pages), GFP_KERNEL);
 	/* caller handles clean up */
 	if (!qpl->pages)
@@ -562,6 +562,7 @@ static int gve_alloc_queue_page_list(str
 		/* caller handles clean up */
 		if (err)
 			return -ENOMEM;
+		qpl->num_entries++;
 	}
 	priv->num_registered_pages += pages;