CVE-2022-49090
In the Linux kernel, the following vulnerability has been resolved: arch/arm64: Fix topology initialization for core scheduling Arm64 systems rely on store_cpu_topology() to call update_siblings_masks() to transfer the toplogy to the various cpu masks.
Does this matter?
Lower severity and a low EPSS score (0.24%). Track it; it rarely justifies an emergency change on its own.
Description
In the Linux kernel, the following vulnerability has been resolved: arch/arm64: Fix topology initialization for core scheduling Arm64 systems rely on store_cpu_topology() to call update_siblings_masks() to transfer the toplogy to the various cpu masks. This needs to be done before the call to notify_cpu_starting() which tells the scheduler about each cpu found, otherwise the core scheduling data structures are setup in a way that does not match the actual topology. With smt_mask not setup correctly we bail on `cpumask_weight(smt_mask) == 1` for !leaders in: notify_cpu_starting() cpuhp_invoke_callback_range() sched_cpu_starting() sched_core_cpu_starting() which leads to rq->core not being correctly set for !leader-rq's. Without this change stress-ng (which enables core scheduling in its prctl tests in newer versions -- i.e. with PR_SCHED_CORE support) causes a warning and then a crash (trimmed for legibility): [ 1853.805168] ------------[ cut here ]------------ [ 1853.809784] task_rq(b)->core != rq->core [ 1853.809792] WARNING: CPU: 117 PID: 0 at kernel/sched/fair.c:11102 cfs_prio_less+0x1b4/0x1c4 ... [ 1854.015210] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010 ... [ 1854.231256] Call trace: [ 1854.233689] pick_next_task+0x3dc/0x81c [ 1854.237512] __schedule+0x10c/0x4cc [ 1854.240988] schedule_idle+0x34/0x54
- CVSS 3.1
- 5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.24% probability · 15th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-476
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/5524cbb1bfcdff0cad0aaa9f94e6092002a07259Patch
- https://git.kernel.org/stable/c/790c1567582bda8f1153015436e3330a7c6eb278Patch
- https://git.kernel.org/stable/c/87f5d66daa5f457449bb95d6b8d18bb7596aa627Patch
- https://git.kernel.org/stable/c/c78a1b2d0bff678570c8dc9f14035606f5e5257dPatch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.