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UBUNTU-CVE-2024-56640 High

UBUNTU-CVE-2024-56640

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.

Exploit probability Not scored
Published December 27, 2024
Required by Not available
Last source change August 17, 2026

02 / AFFECTED SOFTWARE

Affected packages

Ubuntu:Pro:FIPS-updates:20.04:LTS linux-aws-fips

69 explicit affected versions

Ubuntu:24.04:LTS linux-gkeop

8 explicit affected versions

Ubuntu:Pro:FIPS:20.04:LTS linux-aws-fips

1 explicit affected versions

Ubuntu:Pro:18.04:LTS linux-gcp-5.4

105 explicit affected versions

Ubuntu:18.04:LTS linux-gcp-5.3

13 explicit affected versions

Ubuntu:20.04:LTS linux-riscv-5.8

10 explicit affected versions

Ubuntu:20.04:LTS linux-oracle-5.13

12 explicit affected versions

Ubuntu:Pro:20.04:LTS linux-nvidia-tegra-5.15

15 explicit affected versions

Ubuntu:Pro:18.04:LTS linux-aws-5.4

103 explicit affected versions

Ubuntu:22.04:LTS linux-starfive-6.2

3 explicit affected versions

Ubuntu:20.04:LTS linux-riscv-5.11

13 explicit affected versions

Ubuntu:20.04:LTS linux-azure-fde

26 explicit affected versions

Ubuntu:22.04:LTS linux-riscv-6.8

15 explicit affected versions

Ubuntu:24.04:LTS linux-xilinx

7 explicit affected versions

Ubuntu:Pro:20.04:LTS linux-aws

117 explicit affected versions

Ubuntu:22.04:LTS linux-gcp

62 explicit affected versions

Ubuntu:22.04:LTS linux-nvidia-6.2

7 explicit affected versions

Ubuntu:Pro:Realtime:22.04:LTS linux-realtime

60 explicit affected versions

Ubuntu:22.04:LTS linux-hwe-6.5

13 explicit affected versions

Ubuntu:18.04:LTS linux-hwe

43 explicit affected versions

Ubuntu:Pro:FIPS-updates:20.04:LTS linux-gcp-fips

71 explicit affected versions

Ubuntu:Pro:20.04:LTS linux-kvm

113 explicit affected versions

Ubuntu:Pro:FIPS-updates:22.04:LTS linux-aws-fips

24 explicit affected versions

Ubuntu:20.04:LTS linux-azure-5.8

7 explicit affected versions

Ubuntu:22.04:LTS linux-gcp-6.2

12 explicit affected versions

Ubuntu:Pro:FIPS-preview:22.04:LTS linux-aws-fips

2 explicit affected versions

Ubuntu:20.04:LTS linux-gke

51 explicit affected versions

Ubuntu:22.04:LTS linux-gcp-5.19

8 explicit affected versions

Ubuntu:Pro:FIPS-updates:22.04:LTS linux-fips

26 explicit affected versions

Ubuntu:20.04:LTS linux-oracle-5.8

5 explicit affected versions

Ubuntu:22.04:LTS linux-riscv-5.19

8 explicit affected versions

Ubuntu:Pro:FIPS:20.04:LTS linux-gcp-fips

1 explicit affected versions

Ubuntu:22.04:LTS linux-hwe-6.2

10 explicit affected versions

Ubuntu:Pro:FIPS-updates:20.04:LTS linux-azure-fips

66 explicit affected versions

Ubuntu:22.04:LTS linux-starfive-5.19

7 explicit affected versions

Ubuntu:24.04:LTS linux-nvidia-6.11

2 explicit affected versions

Ubuntu:20.04:LTS linux-azure-5.15

54 explicit affected versions

Ubuntu:Pro:20.04:LTS linux-azure

110 explicit affected versions

Ubuntu:20.04:LTS linux-intel-iotg-5.15

43 explicit affected versions

Ubuntu:24.04:LTS linux-riscv

21 explicit affected versions

Ubuntu:22.04:LTS linux-raspi

60 explicit affected versions

Ubuntu:22.04:LTS linux-oracle-6.8

16 explicit affected versions

Ubuntu:22.04:LTS linux-starfive-6.5

11 explicit affected versions

Ubuntu:Pro:20.04:LTS linux-iot

47 explicit affected versions

Ubuntu:22.04:LTS linux-ibm

59 explicit affected versions

Ubuntu:18.04:LTS linux-oem

50 explicit affected versions

Ubuntu:18.04:LTS linux-aws-5.0

6 explicit affected versions

Ubuntu:20.04:LTS linux-aws-5.11

12 explicit affected versions

Ubuntu:22.04:LTS linux-oem-6.5

19 explicit affected versions

Ubuntu:20.04:LTS linux-raspi2

6 explicit affected versions

Ubuntu:22.04:LTS linux

69 explicit affected versions

Ubuntu:22.04:LTS linux-gkeop

54 explicit affected versions

Ubuntu:Pro:FIPS-updates:20.04:LTS linux-fips

85 explicit affected versions

Ubuntu:22.04:LTS linux-azure

62 explicit affected versions

Ubuntu:20.04:LTS linux-lowlatency-hwe-5.15

55 explicit affected versions

Ubuntu:22.04:LTS linux-riscv-6.5

10 explicit affected versions

Ubuntu:22.04:LTS linux-ibm-6.8

12 explicit affected versions

Ubuntu:24.04:LTS linux-oem-6.8

19 explicit affected versions

Ubuntu:22.04:LTS linux-gke

61 explicit affected versions

Ubuntu:22.04:LTS linux-azure-5.19

7 explicit affected versions

Ubuntu:Pro:20.04:LTS linux-gcp

118 explicit affected versions

Ubuntu:24.04:LTS linux-raspi-realtime

1 explicit affected versions

Ubuntu:22.04:LTS linux-gcp-6.5

13 explicit affected versions

Ubuntu:24.04:LTS linux-nvidia

18 explicit affected versions

Ubuntu:20.04:LTS linux-oem-5.14

35 explicit affected versions

Ubuntu:Pro:FIPS-updates:22.04:LTS linux-gcp-fips

21 explicit affected versions

Ubuntu:22.04:LTS linux-nvidia-tegra

19 explicit affected versions

Ubuntu:20.04:LTS linux-hwe-5.8

21 explicit affected versions

Ubuntu:20.04:LTS linux-gke-5.15

18 explicit affected versions

Ubuntu:Pro:FIPS-updates:22.04:LTS linux-azure-fips

20 explicit affected versions

Ubuntu:22.04:LTS linux-azure-fde

64 explicit affected versions

Ubuntu:24.04:LTS linux-oracle

21 explicit affected versions

Ubuntu:Pro:18.04:LTS linux-hwe-5.4

115 explicit affected versions

Ubuntu:20.04:LTS linux-hwe-5.13

16 explicit affected versions

Ubuntu:20.04:LTS linux-aws-5.13

13 explicit affected versions

Ubuntu:20.04:LTS linux-aws-5.8

4 explicit affected versions

Ubuntu:16.04:LTS linux-hwe-edge

23 explicit affected versions

Ubuntu:24.04:LTS linux

26 explicit affected versions

Ubuntu:22.04:LTS linux-lowlatency-hwe-6.2

10 explicit affected versions

Ubuntu:24.04:LTS linux-aws

22 explicit affected versions

Ubuntu:24.04:LTS linux-hwe-6.11

2 explicit affected versions

Ubuntu:18.04:LTS linux-oracle-5.0

7 explicit affected versions

Ubuntu:20.04:LTS linux-riscv

12 explicit affected versions

Ubuntu:24.04:LTS linux-azure-6.11

1 explicit affected versions

Ubuntu:20.04:LTS linux-riscv-5.15

52 explicit affected versions

Ubuntu:20.04:LTS linux-gcp-5.11

12 explicit affected versions

Ubuntu:22.04:LTS linux-azure-6.5

14 explicit affected versions

Ubuntu:22.04:LTS linux-intel-iot-realtime
Ubuntu:22.04:LTS linux-azure-fde-6.2

10 explicit affected versions

Ubuntu:20.04:LTS linux-intel-5.13

7 explicit affected versions

Ubuntu:24.04:LTS linux-nvidia-tegra

2 explicit affected versions

Ubuntu:Pro:18.04:LTS linux-azure-5.4

99 explicit affected versions

Ubuntu:20.04:LTS linux-oem-5.13

12 explicit affected versions

Ubuntu:Pro:20.04:LTS linux-raspi

101 explicit affected versions

Ubuntu:20.04:LTS linux-oracle-5.11

12 explicit affected versions

Ubuntu:Pro:Realtime:22.04:LTS linux-realtime-6.8

16 explicit affected versions

Ubuntu:22.04:LTS linux-nvidia-tegra-igx

15 explicit affected versions

Ubuntu:22.04:LTS linux-azure-6.8

13 explicit affected versions

Ubuntu:18.04:LTS linux-hwe-edge

10 explicit affected versions

Ubuntu:18.04:LTS linux-gke-5.4

37 explicit affected versions

Ubuntu:24.04:LTS linux-azure-nvidia

1 explicit affected versions

Ubuntu:22.04:LTS linux-oracle-6.5

13 explicit affected versions

Ubuntu:22.04:LTS linux-lowlatency-hwe-6.8

14 explicit affected versions

Ubuntu:20.04:LTS linux-oem-5.10

26 explicit affected versions

Ubuntu:20.04:LTS linux-gcp-5.13

13 explicit affected versions

Ubuntu:22.04:LTS linux-xilinx-zynqmp

12 explicit affected versions

Ubuntu:20.04:LTS linux-oem-5.6

29 explicit affected versions

Ubuntu:22.04:LTS linux-lowlatency

66 explicit affected versions

Ubuntu:24.04:LTS linux-nvidia-lowlatency

15 explicit affected versions

Ubuntu:22.04:LTS linux-gcp-6.8

16 explicit affected versions

Ubuntu:Pro:18.04:LTS linux-raspi-5.4

96 explicit affected versions

Ubuntu:22.04:LTS linux-aws

61 explicit affected versions

Ubuntu:18.04:LTS linux-gke-4.15

33 explicit affected versions

Ubuntu:22.04:LTS linux-riscv

23 explicit affected versions

Ubuntu:18.04:LTS linux-aws-5.3

10 explicit affected versions

Ubuntu:Pro:FIPS-updates:24.04:LTS linux-fips

1 explicit affected versions

Ubuntu:Nvidia-BlueField:24.04:LTS linux-bluefield

11 explicit affected versions

Ubuntu:20.04:LTS linux-hwe-5.11

12 explicit affected versions

Ubuntu:20.04:LTS linux-oracle-5.15

52 explicit affected versions

Ubuntu:22.04:LTS linux-nvidia

46 explicit affected versions

Ubuntu:22.04:LTS linux-oracle

62 explicit affected versions

Ubuntu:22.04:LTS linux-lowlatency-hwe-5.19

10 explicit affected versions

Ubuntu:22.04:LTS linux-oem-5.17

26 explicit affected versions

Ubuntu:24.04:LTS linux-azure

20 explicit affected versions

Ubuntu:Pro:FIPS-preview:22.04:LTS linux-azure-fips

1 explicit affected versions

Ubuntu:22.04:LTS linux-hwe-6.8

11 explicit affected versions

Ubuntu:24.04:LTS linux-raspi

23 explicit affected versions

Ubuntu:22.04:LTS linux-kvm

63 explicit affected versions

Ubuntu:24.04:LTS linux-gcp

24 explicit affected versions

Ubuntu:22.04:LTS linux-azure-6.2

13 explicit affected versions

Ubuntu:24.04:LTS linux-ibm

21 explicit affected versions

Ubuntu:Pro:18.04:LTS linux-ibm-5.4

73 explicit affected versions

Ubuntu:22.04:LTS linux-oem-6.0

16 explicit affected versions

Ubuntu:20.04:LTS linux-gcp-5.15

53 explicit affected versions

Ubuntu:22.04:LTS linux-azure-fde-5.19

3 explicit affected versions

Ubuntu:Pro:20.04:LTS linux

126 explicit affected versions

Ubuntu:Pro:FIPS:20.04:LTS linux-azure-fips

1 explicit affected versions

Ubuntu:24.04:LTS linux-gcp-6.11

1 explicit affected versions

Ubuntu:24.04:LTS linux-oem-6.11

9 explicit affected versions

Ubuntu:Pro:Realtime:24.04:LTS linux-raspi-realtime

20 explicit affected versions

Ubuntu:20.04:LTS linux-azure-5.13

12 explicit affected versions

Ubuntu:22.04:LTS linux-intel-iotg

49 explicit affected versions

Ubuntu:22.04:LTS linux-oem-6.1

27 explicit affected versions

Ubuntu:Nvidia-BlueField:22.04:LTS linux-bluefield

36 explicit affected versions

Ubuntu:Pro:20.04:LTS linux-oracle

115 explicit affected versions

Ubuntu:Pro:FIPS:20.04:LTS linux-fips

1 explicit affected versions

Ubuntu:22.04:LTS linux-nvidia-6.8

17 explicit affected versions

Ubuntu:Pro:Realtime:24.04:LTS linux-realtime

20 explicit affected versions

Ubuntu:22.04:LTS linux-lowlatency-hwe-6.5

13 explicit affected versions

Ubuntu:Pro:18.04:LTS linux-oracle-5.4

104 explicit affected versions

Ubuntu:20.04:LTS linux-azure-5.11

13 explicit affected versions

Ubuntu:Pro:20.04:LTS linux-bluefield

75 explicit affected versions

Ubuntu:Pro:20.04:LTS linux-xilinx-zynqmp

50 explicit affected versions

Ubuntu:18.04:LTS linux-azure

44 explicit affected versions

Ubuntu:18.04:LTS linux-azure-5.3

16 explicit affected versions

Ubuntu:22.04:LTS linux-hwe-5.19

11 explicit affected versions

Ubuntu:20.04:LTS linux-gkeop-5.15

45 explicit affected versions

Ubuntu:18.04:LTS linux-gkeop-5.4

37 explicit affected versions

Ubuntu:24.04:LTS linux-lowlatency

25 explicit affected versions

Ubuntu:22.04:LTS linux-aws-6.5

14 explicit affected versions

Ubuntu:18.04:LTS linux-gcp

38 explicit affected versions

Ubuntu:20.04:LTS linux-hwe-5.15

53 explicit affected versions

Ubuntu:18.04:LTS linux-oracle-5.3

9 explicit affected versions

Ubuntu:20.04:LTS linux-aws-5.15

51 explicit affected versions

Ubuntu:20.04:LTS linux-ibm-5.15

33 explicit affected versions

Ubuntu:20.04:LTS linux-gcp-5.8

4 explicit affected versions

Ubuntu:24.04:LTS linux-realtime

1 explicit affected versions

Ubuntu:Pro:FIPS-preview:22.04:LTS linux-fips

1 explicit affected versions

Ubuntu:Pro:FIPS-preview:22.04:LTS linux-gcp-fips

1 explicit affected versions

Ubuntu:22.04:LTS linux-aws-5.19

10 explicit affected versions

Ubuntu:22.04:LTS linux-allwinner-5.19

8 explicit affected versions

Ubuntu:24.04:LTS linux-gke

19 explicit affected versions

Ubuntu:Pro:20.04:LTS linux-ibm

83 explicit affected versions

Ubuntu:22.04:LTS linux-aws-6.2

14 explicit affected versions

Ubuntu:18.04:LTS linux-azure-edge

4 explicit affected versions

Ubuntu:20.04:LTS linux-gkeop

78 explicit affected versions

Ubuntu:22.04:LTS linux-nvidia-6.5

11 explicit affected versions

Ubuntu:22.04:LTS linux-realtime

1 explicit affected versions

Ubuntu:22.04:LTS linux-aws-6.8

14 explicit affected versions

03 / CONNECTIONS

Connected vulnerabilities

04 / EVIDENCE

Source records

Open Source Vulnerabilities UBUNTU-CVE-2024-56640

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.

View original source

05 / REFERENCES

Further evidence