From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?unknown-8bit?q?Bj=C3=B6rn_T=C3=B6pel?= Date: Tue, 25 Aug 2020 11:16:29 +0200 Subject: [Intel-wired-lan] [PATCH net 3/3] ice: avoid premature Rx buffer reuse In-Reply-To: <20200825091629.12949-1-bjorn.topel@gmail.com> References: <20200825091629.12949-1-bjorn.topel@gmail.com> Message-ID: <20200825091629.12949-4-bjorn.topel@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: intel-wired-lan@osuosl.org List-ID: From: Bj?rn T?pel The page recycle code, incorrectly, relied on that a page fragment could not be freed inside xdp_do_redirect(). This assumption leads to that page fragments that are used by the stack/XDP redirect can be reused and overwritten. To avoid this, store the page count prior invoking xdp_do_redirect(). Fixes: efc2214b6047 ("ice: Add support for XDP") Signed-off-by: Bj?rn T?pel --- drivers/net/ethernet/intel/ice/ice_txrx.c | 31 ++++++++++++++++------- 1 file changed, 22 insertions(+), 9 deletions(-) diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.c b/drivers/net/ethernet/intel/ice/ice_txrx.c index 9d0d6b0025cf..03a88c8f17b7 100644 --- a/drivers/net/ethernet/intel/ice/ice_txrx.c +++ b/drivers/net/ethernet/intel/ice/ice_txrx.c @@ -768,7 +768,8 @@ ice_rx_buf_adjust_pg_offset(struct ice_rx_buf *rx_buf, unsigned int size) * pointing to; otherwise, the DMA mapping needs to be destroyed and * page freed */ -static bool ice_can_reuse_rx_page(struct ice_rx_buf *rx_buf) +static bool ice_can_reuse_rx_page(struct ice_rx_buf *rx_buf, + int rx_buf_pgcnt) { unsigned int pagecnt_bias = rx_buf->pagecnt_bias; struct page *page = rx_buf->page; @@ -779,7 +780,7 @@ static bool ice_can_reuse_rx_page(struct ice_rx_buf *rx_buf) #if (PAGE_SIZE < 8192) /* if we are only owner of page we can reuse it */ - if (unlikely((page_count(page) - pagecnt_bias) > 1)) + if (unlikely((rx_buf_pgcnt - pagecnt_bias) > 1)) return false; #else #define ICE_LAST_OFFSET \ @@ -859,6 +860,15 @@ ice_reuse_rx_page(struct ice_ring *rx_ring, struct ice_rx_buf *old_buf) new_buf->pagecnt_bias = old_buf->pagecnt_bias; } +static int ice_rx_buf_page_count(struct ice_rx_buf *rx_buf) +{ +#if (PAGE_SIZE < 8192) + return page_count(rx_buf->page); +#else + return 0; +#endif +} + /** * ice_get_rx_buf - Fetch Rx buffer and synchronize data for use * @rx_ring: Rx descriptor ring to transact packets on @@ -870,11 +880,13 @@ ice_reuse_rx_page(struct ice_ring *rx_ring, struct ice_rx_buf *old_buf) */ static struct ice_rx_buf * ice_get_rx_buf(struct ice_ring *rx_ring, struct sk_buff **skb, - const unsigned int size) + const unsigned int size, + int *rx_buf_pgcnt) { struct ice_rx_buf *rx_buf; rx_buf = &rx_ring->rx_buf[rx_ring->next_to_clean]; + *rx_buf_pgcnt = ice_rx_buf_page_count(rx_buf); prefetchw(rx_buf->page); *skb = rx_buf->skb; @@ -1017,7 +1029,7 @@ ice_construct_skb(struct ice_ring *rx_ring, struct ice_rx_buf *rx_buf, * of the rx_buf. It will either recycle the buffer or unmap it and free * the associated resources. */ -static void ice_put_rx_buf(struct ice_ring *rx_ring, struct ice_rx_buf *rx_buf) +static void ice_put_rx_buf(struct ice_ring *rx_ring, struct ice_rx_buf *rx_buf, int rx_buf_pgcnt) { u16 ntc = rx_ring->next_to_clean + 1; @@ -1028,7 +1040,7 @@ static void ice_put_rx_buf(struct ice_ring *rx_ring, struct ice_rx_buf *rx_buf) if (!rx_buf) return; - if (ice_can_reuse_rx_page(rx_buf)) { + if (ice_can_reuse_rx_page(rx_buf, rx_buf_pgcnt)) { /* hand second half of page back to the ring */ ice_reuse_rx_page(rx_ring, rx_buf); } else { @@ -1088,6 +1100,7 @@ int ice_clean_rx_irq(struct ice_ring *rx_ring, int budget) unsigned int xdp_res, xdp_xmit = 0; struct bpf_prog *xdp_prog = NULL; struct xdp_buff xdp; + int rx_buf_pgcnt; bool failure; xdp.rxq = &rx_ring->xdp_rxq; @@ -1125,7 +1138,7 @@ int ice_clean_rx_irq(struct ice_ring *rx_ring, int budget) dma_rmb(); if (rx_desc->wb.rxdid == FDIR_DESC_RXDID || !rx_ring->netdev) { - ice_put_rx_buf(rx_ring, NULL); + ice_put_rx_buf(rx_ring, NULL, 0); cleaned_count++; continue; } @@ -1134,7 +1147,7 @@ int ice_clean_rx_irq(struct ice_ring *rx_ring, int budget) ICE_RX_FLX_DESC_PKT_LEN_M; /* retrieve a buffer from the ring */ - rx_buf = ice_get_rx_buf(rx_ring, &skb, size); + rx_buf = ice_get_rx_buf(rx_ring, &skb, size, &rx_buf_pgcnt); if (!size) { xdp.data = NULL; @@ -1174,7 +1187,7 @@ int ice_clean_rx_irq(struct ice_ring *rx_ring, int budget) total_rx_pkts++; cleaned_count++; - ice_put_rx_buf(rx_ring, rx_buf); + ice_put_rx_buf(rx_ring, rx_buf, rx_buf_pgcnt); continue; construct_skb: if (skb) { @@ -1193,7 +1206,7 @@ int ice_clean_rx_irq(struct ice_ring *rx_ring, int budget) break; } - ice_put_rx_buf(rx_ring, rx_buf); + ice_put_rx_buf(rx_ring, rx_buf, rx_buf_pgcnt); cleaned_count++; /* skip if it is NOP desc */ -- 2.25.1