[PATCH AUTOSEL 5.17 18/23] net: atlantic: fix "frag[0] not initialized"

Sasha Levin
2022-05-18T12:28:40Z

From: Grant Grundler <grundler@chromium.org>

[ Upstream commit 62e0ae0f4020250f961cf8d0103a4621be74e077 ]

In aq_ring_rx_clean(), if buff->is_eop is not set AND
buff->len < AQ_CFG_RX_HDR_SIZE, then hdr_len remains equal to
buff->len and skb_add_rx_frag(xxx, *0*, ...) is not called.

The loop following this code starts calling skb_add_rx_frag() starting
with i=1 and thus frag[0] is never initialized. Since i is initialized
to zero at the top of the primary loop, we can just reference and
post-increment i instead of hardcoding the 0 when calling
skb_add_rx_frag() the first time.

Reported-by: Aashay Shringarpure <aashay@google.com>
Reported-by: Yi Chou <yich@google.com>
Reported-by: Shervin Oloumi <enlightened@google.com>
Signed-off-by: Grant Grundler <grundler@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/aquantia/atlantic/aq_ring.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
index 77e76c9efd32..440423b0e8ea 100644
--- a/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
+++ b/drivers/net/ethernet/aquantia/atlantic/aq_ring.c
@@ -446,7 +446,7 @@ int aq_ring_rx_clean(struct aq_ring_s *self,
ALIGN(hdr_len, sizeof(long)));

if (buff->len - hdr_len > 0) {
- skb_add_rx_frag(skb, 0, buff->rxdata.page,
+ skb_add_rx_frag(skb, i++, buff->rxdata.page,
buff->rxdata.pg_off + hdr_len,
buff->len - hdr_len,
AQ_CFG_RX_FRAME_MAX);
@@ -455,7 +455,6 @@ int aq_ring_rx_clean(struct aq_ring_s *self,

if (!buff->is_eop) {
buff_ = buff;
- i = 1U;
do {
next_ = buff_->next;
buff_ = &self->buff_ring[next_];
--
2.35.1