qede_rx_build_skb() and qede_tpa_rx_build_skb() do not check for a NULL return from qede_build_skb(). When it returns NULL under memory pressure, the functions still consume a BD from the ring before returning NULL. The callers then recycle additional BDs, resulting in one extra BD being consumed (off-by-one). This desynchronizes the BD ring, which can corrupt DMA page reference counts and lead to SLUB freelist corruption. Commit 4e910dbe3650 ("qede: confirm skb is allocated before using") added a NULL check inside qede_build_skb() to prevent a NULL pointer dereference, but did not address the missing NULL checks in the callers, making this off-by-one reachable. Fix this by adding NULL checks for the return value of qede_build_skb() in both qede_rx_build_skb() and qede_tpa_rx_build_skb(), returning NULL immediately before any BD ring manipulation. Fixes: 4e910dbe3650 ("qede: confirm skb is allocated before using") Signed-off-by: Shigeru Yoshida --- drivers/net/ethernet/qlogic/qede/qede_fp.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/net/ethernet/qlogic/qede/qede_fp.c b/drivers/net/ethernet/qlogic/qede/qede_fp.c index 33e18bb69774..c11e0d8f98aa 100644 --- a/drivers/net/ethernet/qlogic/qede/qede_fp.c +++ b/drivers/net/ethernet/qlogic/qede/qede_fp.c @@ -765,6 +765,9 @@ qede_tpa_rx_build_skb(struct qede_dev *edev, struct sk_buff *skb; skb = qede_build_skb(rxq, bd, len, pad); + if (unlikely(!skb)) + return NULL; + bd->page_offset += rxq->rx_buf_seg_size; if (bd->page_offset == PAGE_SIZE) { @@ -812,6 +815,8 @@ qede_rx_build_skb(struct qede_dev *edev, } skb = qede_build_skb(rxq, bd, len, pad); + if (unlikely(!skb)) + return NULL; if (unlikely(qede_realloc_rx_buffer(rxq, bd))) { /* Incr page ref count to reuse on allocation failure so -- 2.54.0