CVE-2026-72339qede: fix off-by-one in BD ring consumption on build_skb failure

Official description

In the Linux kernel, the following vulnerability has been resolved: 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.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/ecc05d4b20220a09c9c69584fc46ca55248a374a
• https://git.kernel.org/stable/c/07be8b8adf91b7ada4c3dacce064d572a6066421
• https://git.kernel.org/stable/c/1624aa100c0b218181aa74e3696a389b509298cb
• https://git.kernel.org/stable/c/0bf78df2d3ecb1f4964ff42a7327d25845955153
• https://git.kernel.org/stable/c/814a5edac8c9fc04051808d5faaa93768e989281
• https://git.kernel.org/stable/c/b066420e57f3402a52c998678b4678252ac9bb63
• https://git.kernel.org/stable/c/982d6d6bc059c5dff37a2201c2f08c14bcfcbd20
• https://git.kernel.org/stable/c/a0a558ca7e75b49e71f8c545c30e8c005e6e4e2f