net/mlx5e: RX, Fix XDP multi-buf frag counting for legacy RQ_CVE-2026-43464

{
    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/mlx5e: RX, Fix XDP multi-buf frag counting for legacy RQ\n\nXDP multi-buf programs can modify the layout of the XDP buffer when the\nprogram calls bpf_xdp_pull_data() or bpf_xdp_adjust_tail(). The\nreferenced commit in the fixes tag corrected the assumption in the mlx5\ndriver that the XDP buffer layout doesn't change during a program\nexecution. However, this fix introduced another issue: the dropped\nfragments still need to be counted on the driver side to avoid page\nfragment reference counting issues.\n\nSuch issue can be observed with the\ntest_xdp_native_adjst_tail_shrnk_data selftest when using a payload of\n3600 and shrinking by 256 bytes (an upcoming selftest patch): the last\nfragment gets released by the XDP code but doesn't get tracked by the\ndriver. This results in a negative pp_ref_count during page release and\nthe following splat:\n\n  WARNING: include/net/page_pool/helpers.h:297 at mlx5e_page_release_fragmented.isra.0+0x4a/0x50 [mlx5_core], CPU#12: ip/3137\n  Modules linked in: [...]\n  CPU: 12 UID: 0 PID: 3137 Comm: ip Not tainted 6.19.0-rc3+ #12 NONE\n  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014\n  RIP: 0010:mlx5e_page_release_fragmented.isra.0+0x4a/0x50 [mlx5_core]\n  [...]\n  Call Trace:\n   <TASK>\n   mlx5e_dealloc_rx_wqe+0xcb/0x1a0 [mlx5_core]\n   mlx5e_free_rx_descs+0x7f/0x110 [mlx5_core]\n   mlx5e_close_rq+0x50/0x60 [mlx5_core]\n   mlx5e_close_queues+0x36/0x2c0 [mlx5_core]\n   mlx5e_close_channel+0x1c/0x50 [mlx5_core]\n   mlx5e_close_channels+0x45/0x80 [mlx5_core]\n   mlx5e_safe_switch_params+0x1a5/0x230 [mlx5_core]\n   mlx5e_change_mtu+0xf3/0x2f0 [mlx5_core]\n   netif_set_mtu_ext+0xf1/0x230\n   do_setlink.isra.0+0x219/0x1180\n   rtnl_newlink+0x79f/0xb60\n   rtnetlink_rcv_msg+0x213/0x3a0\n   netlink_rcv_skb+0x48/0xf0\n   netlink_unicast+0x24a/0x350\n   netlink_sendmsg+0x1ee/0x410\n   __sock_sendmsg+0x38/0x60\n   ____sys_sendmsg+0x232/0x280\n   ___sys_sendmsg+0x78/0xb0\n   __sys_sendmsg+0x5f/0xb0\n   [...]\n   do_syscall_64+0x57/0xc50\n\nThis patch fixes the issue by doing page frag counting on all the\noriginal XDP buffer fragments for all relevant XDP actions (XDP_TX ,\nXDP_REDIRECT and XDP_PASS). This is basically reverting to the original\ncounting before the commit in the fixes tag.\n\nAs frag_page is still pointing to the original tail, the nr_frags\nparameter to xdp_update_skb_frags_info() needs to be calculated\nin a different way to reflect the new nr_frags.",
    "published": "2026-05-08T14:22:26.039Z",
    "modified": "2026-05-11T06:34:51.018Z",
    "type": "cve",
    "title": "net/mlx5e: RX, Fix XDP multi-buf frag counting for legacy RQ",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/c74557495efb4bd0adefdfc8678ecdbc82a06da3\nhttps://git.kernel.org/stable/c/03cb50e5b74fce8bf6d92b860371b66253cf0f8d\nhttps://git.kernel.org/stable/c/a6413e6f6c9d9bb9833324cb3753582f7bc0f2fa",
    "id": "CVE-2026-43464",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux afd5ba577c10639f62e8120df67dc70ea4b61176\nLinux Linux afd5ba577c10639f62e8120df67dc70ea4b61176\nLinux Linux afd5ba577c10639f62e8120df67dc70ea4b61176\nLinux Linux 72328f25755ee966724f46e3a0e8e59bef2091ba\nLinux Linux 0049fd63881505566824e88cfa624638f921c808\nLinux Linux d969645b9b7810289bf3c353ea06957373756b8e\nLinux Linux 6.18",
    "sourceHref": "",
    "cvss": {
        "score": 7.5,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
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            "baseScore": 0,
            "baseSeverity": "",
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            "privilegesRequired": "",
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    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "afd5ba577c10639f62e8120df67dc70ea4b61176",
    "vendor": "Linux",
    "ai_description": "",
    "ai_severity": "",
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    "ai_score": 0
}