CVE-2025-38261

/// Technical description

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

riscv: save the SR_SUM status over switches

When threads/tasks are switched we need to ensure the old execution's

SR_SUM state is saved and the new thread has the old SR_SUM state

restored.

The issue was seen under heavy load especially with the syz-stress tool

running, with crashes as follows in schedule_tail:

Unable to handle kernel access to user memory without uaccess routines

at virtual address 000000002749f0d0

Oops [#1]

Modules linked in:

CPU: 1 PID: 4875 Comm: syz-executor.0 Not tainted

5.12.0-rc2-syzkaller-00467-g0d7588ab9ef9 #0

Hardware name: riscv-virtio,qemu (DT)

epc : schedule_tail+0x72/0xb2 kernel/sched/core.c:4264

ra : task_pid_vnr include/linux/sched.h:1421 [inline]

ra : schedule_tail+0x70/0xb2 kernel/sched/core.c:4264

epc : ffffffe00008c8b0 ra : ffffffe00008c8ae sp : ffffffe025d17ec0

gp : ffffffe005d25378 tp : ffffffe00f0d0000 t0 : 0000000000000000

t1 : 0000000000000001 t2 : 00000000000f4240 s0

/// 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