CVE-2024-56640

/// Technical description

In 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 [s

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References