Answer in brief
CVE-2024-56640 records a Unknown severity vulnerability in net/smc: fix LGR and link use-after-free issue. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 <f502a88fdd415647a1f2dc45fac71b9c522a052b || >=3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 <0cf598548a6c36d90681d53c6b77d52363f2f295 || >=3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 <673d606683ac70bc074ca6676b938bff18635226 || >=3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 <6f0ae06a234a78ae137064f2c89135ac078a00eb || >=3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 <2c7f14ed9c19ec0f149479d1c2842ec1f9bf76d7 | f502a88fdd415647a1f2dc45fac71b9c522a052b, 0cf598548a6c36d90681d53c6b77d52363f2f295, 673d606683ac70bc074ca6676b938bff18635226, 6f0ae06a234a78ae137064f2c89135ac078a00eb, 2c7f14ed9c19ec0f149479d1c2842ec1f9bf76d7 |
| Linux/Linuxgeneric | 4.18 | Not reported |
Published upstream
Dec 27, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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 [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.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2024-56640 records a Unknown severity vulnerability in net/smc: fix LGR and link use-after-free issue. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 <f502a88fdd415647a1f2dc45fac71b9c522a052b || >=3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 <0cf598548a6c36d90681d53c6b77d52363f2f295 || >=3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 <673d606683ac70bc074ca6676b938bff18635226 || >=3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 <6f0ae06a234a78ae137064f2c89135ac078a00eb || >=3b2dec2603d5b06ad3af71c1164ca0b92df3d2a8 <2c7f14ed9c19ec0f149479d1c2842ec1f9bf76d7 | f502a88fdd415647a1f2dc45fac71b9c522a052b, 0cf598548a6c36d90681d53c6b77d52363f2f295, 673d606683ac70bc074ca6676b938bff18635226, 6f0ae06a234a78ae137064f2c89135ac078a00eb, 2c7f14ed9c19ec0f149479d1c2842ec1f9bf76d7 |
| Linux/Linuxgeneric | 4.18 | Not reported |
Published upstream
Dec 27, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
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 [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.
Quoted source text, attributed separately from HOL analysis.