GHSA-MXWC-7773-PQQC
Vulnerability from github – Published: 2024-12-27 15:31 – Updated: 2025-11-03 21:31In the Linux kernel, the following vulnerability has been resolved:
net/smc: fix LGR and link use-after-free issue
We encountered a LGR/link use-after-free issue, which manifested as the LGR/link refcnt reaching 0 early and entering the clear process, making resource access unsafe.
refcount_t: addition on 0; use-after-free. WARNING: CPU: 14 PID: 107447 at lib/refcount.c:25 refcount_warn_saturate+0x9c/0x140 Workqueue: events smc_lgr_terminate_work [smc] Call trace: refcount_warn_saturate+0x9c/0x140 __smc_lgr_terminate.part.45+0x2a8/0x370 [smc] smc_lgr_terminate_work+0x28/0x30 [smc] process_one_work+0x1b8/0x420 worker_thread+0x158/0x510 kthread+0x114/0x118
or
refcount_t: underflow; use-after-free. WARNING: CPU: 6 PID: 93140 at lib/refcount.c:28 refcount_warn_saturate+0xf0/0x140 Workqueue: smc_hs_wq smc_listen_work [smc] Call trace: refcount_warn_saturate+0xf0/0x140 smcr_link_put+0x1cc/0x1d8 [smc] smc_conn_free+0x110/0x1b0 [smc] smc_conn_abort+0x50/0x60 [smc] smc_listen_find_device+0x75c/0x790 [smc] smc_listen_work+0x368/0x8a0 [smc] process_one_work+0x1b8/0x420 worker_thread+0x158/0x510 kthread+0x114/0x118
It is caused by repeated release of LGR/link refcnt. One suspect is that smc_conn_free() is called repeatedly because some smc_conn_free() from server listening path are not protected by sock lock.
e.g.
Calls under socklock | smc_listen_work
lock_sock(sk) | smc_conn_abort smc_conn_free | - smc_conn_free - smcr_link_put | - smcr_link_put (duplicated) release_sock(sk)
So here add sock lock protection in smc_listen_work() path, making it exclusive with other connection operations.
{
"affected": [],
"aliases": [
"CVE-2024-56640"
],
"database_specific": {
"cwe_ids": [
"CWE-416"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-12-27T15:15:23Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: fix LGR and link use-after-free issue\n\nWe encountered a LGR/link use-after-free issue, which manifested as\nthe LGR/link refcnt reaching 0 early and entering the clear process,\nmaking resource access unsafe.\n\n refcount_t: addition on 0; use-after-free.\n WARNING: CPU: 14 PID: 107447 at lib/refcount.c:25 refcount_warn_saturate+0x9c/0x140\n Workqueue: events smc_lgr_terminate_work [smc]\n Call trace:\n refcount_warn_saturate+0x9c/0x140\n __smc_lgr_terminate.part.45+0x2a8/0x370 [smc]\n smc_lgr_terminate_work+0x28/0x30 [smc]\n process_one_work+0x1b8/0x420\n worker_thread+0x158/0x510\n kthread+0x114/0x118\n\nor\n\n refcount_t: underflow; use-after-free.\n WARNING: CPU: 6 PID: 93140 at lib/refcount.c:28 refcount_warn_saturate+0xf0/0x140\n Workqueue: smc_hs_wq smc_listen_work [smc]\n Call trace:\n refcount_warn_saturate+0xf0/0x140\n smcr_link_put+0x1cc/0x1d8 [smc]\n smc_conn_free+0x110/0x1b0 [smc]\n smc_conn_abort+0x50/0x60 [smc]\n smc_listen_find_device+0x75c/0x790 [smc]\n smc_listen_work+0x368/0x8a0 [smc]\n process_one_work+0x1b8/0x420\n worker_thread+0x158/0x510\n kthread+0x114/0x118\n\nIt is caused by repeated release of LGR/link refcnt. One suspect is that\nsmc_conn_free() is called repeatedly because some smc_conn_free() from\nserver listening path are not protected by sock lock.\n\ne.g.\n\nCalls under socklock | smc_listen_work\n-------------------------------------------------------\nlock_sock(sk) | smc_conn_abort\nsmc_conn_free | \\- smc_conn_free\n\\- smcr_link_put | \\- smcr_link_put (duplicated)\nrelease_sock(sk)\n\nSo here add sock lock protection in smc_listen_work() path, making it\nexclusive with other connection operations.",
"id": "GHSA-mxwc-7773-pqqc",
"modified": "2025-11-03T21:31:56Z",
"published": "2024-12-27T15:31:55Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-56640"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0cf598548a6c36d90681d53c6b77d52363f2f295"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2c7f14ed9c19ec0f149479d1c2842ec1f9bf76d7"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/673d606683ac70bc074ca6676b938bff18635226"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6f0ae06a234a78ae137064f2c89135ac078a00eb"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f502a88fdd415647a1f2dc45fac71b9c522a052b"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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