CVE-2022-50225
📋 TL;DR
This CVE describes a race condition vulnerability in the RISC-V uprobe implementation in the Linux kernel. When handling user-space probes, improper clearing/setting of the SPIE (Supervisor Previous Interrupt Enable) bit can cause a page fault while interrupts are disabled, leading to a kernel warning and potential system instability. This affects systems running Linux kernels with RISC-V architecture support.
💻 Affected Systems
- Linux kernel
📦 What is this software?
Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →Linux Kernel by Linux
The Linux Kernel is the core component of the Linux operating system, serving as the critical interface between computer hardware and software processes. As the heart of millions of servers, cloud infrastructure, embedded systems, Android devices, and IoT deployments worldwide, the Linux Kernel mana...
Learn more about Linux Kernel →⚠️ Risk & Real-World Impact
Worst Case
Kernel panic or system crash due to the sleeping function being called from invalid context while interrupts are disabled, leading to denial of service.
Likely Case
Kernel warning messages in logs and potential system instability or crashes when uprobe functionality is used on RISC-V systems.
If Mitigated
Minor performance impact from kernel warnings, but system remains operational if uprobe functionality is not actively used.
🎯 Exploit Status
Requires local access and ability to trigger uprobe functionality. More of a stability issue than a security exploit.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Patches available in stable kernel trees (commits: 3811d51778900064d27d8c9a98f73410fb3b471d, 3dbe5829408bc1586f75b4667ef60e5aab0209c7, 73fc099eaefd9a92c83b6c07dad066411fd5a192, c71e000db8536d27ec410abb3e314896a78b4f19)
Vendor Advisory: https://git.kernel.org/stable/c/3811d51778900064d27d8c9a98f73410fb3b471d
Restart Required: Yes
Instructions:
1. Update to a patched Linux kernel version containing the fix commits. 2. For RISC-V specific distributions, check vendor updates. 3. Reboot system after kernel update.
🔧 Temporary Workarounds
Disable uprobe functionality
linuxDisable user-space probe functionality to prevent triggering the vulnerability
echo 0 > /sys/kernel/debug/tracing/uprobe_events
echo 0 > /sys/kernel/debug/tracing/events/uprobes/enable
🧯 If You Can't Patch
- Restrict access to debugfs and tracing functionality to prevent uprobe usage
- Monitor kernel logs for WARN messages related to sleeping functions called from invalid context
🔍 How to Verify
Check if Vulnerable:
Check if system is RISC-V architecture and if uprobe functionality is enabled: 'uname -m' should show riscv and check /sys/kernel/debug/tracing/uprobe_eventsCheck Version:
uname -rVerify Fix Applied:
Check kernel version includes the fix commits or verify with vendor that patch is applied📡 Detection & Monitoring
Log Indicators:
- Kernel WARN messages about 'sleeping function called from invalid context'
- References to 'arch_uprobe_pre_xol' or 'SR_SPIE' in kernel logs
- Page fault errors while interrupts are disabled
Network Indicators:
- None - this is a local kernel issue
SIEM Query:
source="kernel" AND ("sleeping function called from invalid context" OR "arch_uprobe" OR "SR_SPIE")