Huawei EulerOS: CVE-2022-48921: kernel security update

Huawei EulerOS: CVE-2022-48921: kernel security update

Severity

4

CVSS

(AV:L/AC:M/Au:N/C:P/I:P/A:P)

Published

08/22/2024

Created

02/12/2025

Added

02/11/2025

Modified

02/11/2025

Description

In the Linux kernel, the following vulnerability has been resolved: sched/fair: Fix fault in reweight_entity Syzbot found a GPF in reweight_entity. This has been bisected to commit 4ef0c5c6b5ba ("kernel/sched: Fix sched_fork() access an invalid sched_task_group") There is a race between sched_post_fork() and setpriority(PRIO_PGRP) within a thread group that causes a null-ptr-deref in reweight_entity() in CFS. The scenario is that the main process spawns number of new threads, which then call setpriority(PRIO_PGRP, 0, -20), wait, and exit.For each of the new threads the copy_process() gets invoked, which adds the new task_struct and calls sched_post_fork() for it. In the above scenario there is a possibility that setpriority(PRIO_PGRP) and set_one_prio() will be called for a thread in the group that is just being created by copy_process(), and for which the sched_post_fork() has not been executed yet. This will trigger a null pointer dereference in reweight_entity(), as it will try to access the run queue pointer, which hasn't been set. Before the mentioned change the cfs_rq pointer for the taskhas been set in sched_fork(), which is called much earlier in copy_process(), before the new task is added to the thread_group.Now it is done in the sched_post_fork(), which is called after that.To fix the issue the remove the update_load param from the update_load param() function and call reweight_task() only if the task flag doesn't have the TASK_NEW flag set.

Solution(s)

• huawei-euleros-2_0_sp12-upgrade-bpftool
• huawei-euleros-2_0_sp12-upgrade-kernel
• huawei-euleros-2_0_sp12-upgrade-kernel-abi-stablelists
• huawei-euleros-2_0_sp12-upgrade-kernel-tools
• huawei-euleros-2_0_sp12-upgrade-kernel-tools-libs
• huawei-euleros-2_0_sp12-upgrade-python3-perf

References

• https://attackerkb.com/topics/cve-2022-48921
• CVE - 2022-48921
• EulerOS-SA-2025-1192