From: Shigeru Yoshida Date: Tue, 30 Jun 2026 16:46:20 +0000 (+0900) Subject: qede: fix off-by-one in BD ring consumption on build_skb failure X-Git-Tag: v7.2-rc3~29^2~26 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a0a558ca7e75b49e71f8c545c30e8c005e6e4e2f;p=thirdparty%2Fkernel%2Flinux.git qede: fix off-by-one in BD ring consumption on build_skb failure 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: 8a8633978b84 ("qede: Add build_skb() support.") Signed-off-by: Shigeru Yoshida Reviewed-by: Jamie Bainbridge Link: https://patch.msgid.link/20260630164623.3152625-1-syoshida@redhat.com Signed-off-by: Paolo Abeni --- 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