4.14-stable review patch. If anyone has any objections, please let me know.
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From: Aaro Koskinen aaro.koskinen@nokia.com
[ Upstream commit 223a960c01227e4dbcb6f9fa06b47d73bda21274 ]
When using 16K DMA buffers and ring mode, the DES3 refill is not working correctly as the function is using a bogus pointer for checking the private data. As a result stale pointers will remain in the RX descriptor ring, so DMA will now likely overwrite/corrupt some already freed memory.
As simple reproducer, just receive some UDP traffic:
# ifconfig eth0 down; ifconfig eth0 mtu 9000; ifconfig eth0 up # iperf3 -c 192.168.253.40 -u -b 0 -R
If you didn't crash by now check the RX descriptors to find non-contiguous RX buffers:
cat /sys/kernel/debug/stmmaceth/eth0/descriptors_status [...] 1 [0x2be5020]: 0xa3220321 0x9ffc1ffc 0x72d70082 0x130e207e ^^^^^^^^^^^^^^^^^^^^^ 2 [0x2be5040]: 0xa3220321 0x9ffc1ffc 0x72998082 0x1311a07e ^^^^^^^^^^^^^^^^^^^^^
A simple ping test will now report bad data:
# ping -s 8200 192.168.253.40 PING 192.168.253.40 (192.168.253.40) 8200(8228) bytes of data. 8208 bytes from 192.168.253.40: icmp_seq=1 ttl=64 time=1.00 ms wrong data byte #8144 should be 0xd0 but was 0x88
Fix the wrong pointer. Also we must refill DES3 only if the DMA buffer size is 16K.
Fixes: 54139cf3bb33 ("net: stmmac: adding multiple buffers for rx") Signed-off-by: Aaro Koskinen aaro.koskinen@nokia.com Acked-by: Jose Abreu joabreu@synopsys.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/stmicro/stmmac/ring_mode.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/drivers/net/ethernet/stmicro/stmmac/ring_mode.c +++ b/drivers/net/ethernet/stmicro/stmmac/ring_mode.c @@ -114,10 +114,11 @@ static unsigned int stmmac_is_jumbo_frm(
static void stmmac_refill_desc3(void *priv_ptr, struct dma_desc *p) { - struct stmmac_priv *priv = (struct stmmac_priv *)priv_ptr; + struct stmmac_rx_queue *rx_q = priv_ptr; + struct stmmac_priv *priv = rx_q->priv_data;
/* Fill DES3 in case of RING mode */ - if (priv->dma_buf_sz >= BUF_SIZE_8KiB) + if (priv->dma_buf_sz == BUF_SIZE_16KiB) p->des3 = cpu_to_le32(le32_to_cpu(p->des2) + BUF_SIZE_8KiB); }