CVE-2025-39857: net/smc: fix one NULL pointer dereference in smc_ib_is_sg_need_sync()
In the Linux kernel, the following vulnerability has been resolved:
net/smc: fix one NULL pointer dereference in smcibissgneedsync()
BUG: kernel NULL pointer dereference, address: 00000000000002ec PGD 0 P4D 0 Oops: Oops: 0000 [#1] SMP PTI CPU: 28 UID: 0 PID: 343 Comm: kworker/28:1 Kdump: loaded Tainted: G OE 6.17.0-rc2+ #9 NONE Tainted: [O]=OOTMODULE, [E]=UNSIGNEDMODULE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014 Workqueue: smchswq smclistenwork [smc] RIP: 0010:smcibissgneedsync+0x9e/0xd0 [smc] ... Call Trace: <TASK> smcrbufmaplink+0x211/0x2a0 [smc] smcbufcreate+0x522/0x970 [smc] smcbufcreate+0x3a/0x110 [smc] smcfindrdmav2deviceserv+0x18f/0x240 [smc] ? smcvlanbytcpsk+0x7e/0xe0 [smc] smclistenfinddevice+0x1dd/0x2b0 [smc] smclistenwork+0x30f/0x580 [smc] processonework+0x18c/0x340 workerthread+0x242/0x360 kthread+0xe7/0x220 retfromfork+0x13a/0x160 retfromforkasm+0x1a/0x30 </TASK>
If the software RoCE device is used, ibdev->dmadevice is a null pointer. As a result, the problem occurs. Null pointer detection is added to prevent problems.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Update the Linux kernel so the smc driver includes the added NULL pointer detection in smc_ib_is_sg_need_sync() (net/smc: fix one NULL pointer dereference in smc_ib_is_sg_need_sync()) to prevent crashes when ibdev->dma_device is NULL for RoCE device usage.
Linux kernel (net/smc / smc module) Null pointer detection in smc_ib_is_sg_need_sync() = added
Event History
Frequently Asked Questions
What is the severity of CVE-2025-39857?
The severity of CVE-2025-39857 is classified as medium due to the potential for a NULL pointer dereference in the Linux kernel.
How do I fix CVE-2025-39857?
To fix CVE-2025-39857, ensure that you update to the latest version of the Linux kernel that has resolved this vulnerability.
What versions of the Linux kernel are affected by CVE-2025-39857?
CVE-2025-39857 affects specific versions of the Linux kernel, particularly those prior to the patch that addresses the NULL pointer dereference issue.
What impact does CVE-2025-39857 have on system stability?
CVE-2025-39857 can lead to system instability and crashes due to potential unexpected behaviors caused by the NULL pointer dereference.
Is CVE-2025-39857 exploitable remotely?
CVE-2025-39857 is primarily a local vulnerability, meaning it requires local access to exploit, rather than being directly exploitable remotely.