In the Linux kernel, the following vulnerability has been resolved:

net/smc: fix one NULL pointer dereference in smc_ib_is_sg_need_sync()

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]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
Workqueue: smc_hs_wq smc_listen_work [smc]
RIP: 0010:smc_ib_is_sg_need_sync+0x9e/0xd0 [smc]
...
Call Trace:

smcr_buf_map_link+0x211/0x2a0 [smc]
__smc_buf_create+0x522/0x970 [smc]
smc_buf_create+0x3a/0x110 [smc]
smc_find_rdma_v2_device_serv+0x18f/0x240 [smc]
? smc_vlan_by_tcpsk+0x7e/0xe0 [smc]
smc_listen_find_device+0x1dd/0x2b0 [smc]
smc_listen_work+0x30f/0x580 [smc]
process_one_work+0x18c/0x340
worker_thread+0x242/0x360
kthread+0xe7/0x220
ret_from_fork+0x13a/0x160
ret_from_fork_asm+0x1a/0x30

If the software RoCE device is used, ibdev->dma_device is a null pointer.
As a result, the problem occurs. Null pointer detection is added to
prevent problems.

References

• https://nvd.nist.gov/vuln/detail/CVE-2025-39857
• https://git.kernel.org/stable/c/0cdf1fd8fc59d44a48c694324611136910301ef9
• https://git.kernel.org/stable/c/34f17cbe027050b8d5316ea1b6f9bd7c378e92de
• https://git.kernel.org/stable/c/ba1e9421cf1a8369d25c3832439702a015d6b5f9
• https://git.kernel.org/stable/c/eb929910bd4b4165920fa06a87b22cc6cae92e0e
• https://git.kernel.org/stable/c/f18d9b3abf9c6587372cc702f963a7592277ed56
• https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html