linux-kernel - [PATCH for v4.9 LTS 30/86] gianfar: Do not reuse pages from emergency reserve

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Message-ID: <20170617222420.19316-30-alexander.levin@verizon.com>
Date:   Sat, 17 Jun 2017 22:24:37 +0000
From:   "Levin, Alexander (Sasha Levin)" <alexander.levin@...izon.com>
To:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc:     Eric Dumazet <edumazet@...gle.com>,
        Claudiu Manoil <claudiu.manoil@...escale.com>,
        "David S . Miller" <davem@...emloft.net>,
        "Levin, Alexander (Sasha Levin)" <alexander.levin@...izon.com>
Subject: [PATCH for v4.9 LTS 30/86] gianfar: Do not reuse pages from emergency
 reserve

From: Eric Dumazet <edumazet@...gle.com>

[ Upstream commit 69fed99baac186013840ced3524562841296034f ]

A driver using dev_alloc_page() must not reuse a page that had to
use emergency memory reserve.

Otherwise all packets using this page will be immediately dropped,
unless for very specific sockets having SOCK_MEMALLOC bit set.

This issue might be hard to debug, because only a fraction of the RX
ring buffer would suffer from drops.

Fixes: 75354148ce69 ("gianfar: Add paged allocation and Rx S/G")
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Cc: Claudiu Manoil <claudiu.manoil@...escale.com>
Acked-by: Claudiu Manoil <claudiu.manoil@....com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
---
 drivers/net/ethernet/freescale/gianfar.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/freescale/gianfar.c b/drivers/net/ethernet/freescale/gianfar.c
index d391beebe591..3f4e71148808 100644
--- a/drivers/net/ethernet/freescale/gianfar.c
+++ b/drivers/net/ethernet/freescale/gianfar.c
@@ -2951,7 +2951,7 @@ static bool gfar_add_rx_frag(struct gfar_rx_buff *rxb, u32 lstatus,
 	}
 
 	/* try reuse page */
-	if (unlikely(page_count(page) != 1))
+	if (unlikely(page_count(page) != 1 || page_is_pfmemalloc(page)))
 		return false;
 
 	/* change offset to the other half */
-- 
2.11.0