CVE-2025-21803
📋 TL;DR
This CVE describes a race condition vulnerability in the Linux kernel's LoongArch architecture during S3 suspend operations. The issue causes kernel warnings and potential system instability when resuming from sleep, affecting systems running vulnerable Linux kernel versions with LoongArch CPUs.
💻 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
System crash or kernel panic during resume from suspend, leading to data loss or corruption and requiring physical intervention to reboot.
Likely Case
Kernel warnings in system logs and potential temporary system instability during resume from suspend, but no persistent damage.
If Mitigated
Minor performance impact during suspend/resume operations with proper patching.
🎯 Exploit Status
Exploitation requires local access and ability to trigger S3 suspend state. This appears to be a stability bug rather than a security vulnerability with traditional exploit potential.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Kernel versions containing commits 194d26a5a43c26dc98a9b4e2c1d521dcb84dd1bf, 26c0a2d93af55d30a46d5f45d3e9c42cde730168, 8682a71a7f6de7c683f31b4334b04e19685a05f9, or d49ab6857d98266010f3446c9c2063014db5b654
Vendor Advisory: https://git.kernel.org/stable/c/194d26a5a43c26dc98a9b4e2c1d521dcb84dd1bf
Restart Required: Yes
Instructions:
1. Update to a patched Linux kernel version from your distribution vendor. 2. For custom kernels, apply the relevant kernel commits. 3. Reboot the system to load the new kernel.
🔧 Temporary Workarounds
Disable S3 Suspend
linuxPrevent the system from entering S3 suspend state where the vulnerability triggers.
echo deep > /sys/power/mem_sleep
echo 0 > /sys/power/pm_test
Disable ACPI Wakeup GPEs
linuxDisable the specific ACPI functionality that causes the race condition.
echo 0 > /sys/firmware/acpi/interrupts/gpe_all
🧯 If You Can't Patch
- Disable S3 suspend functionality entirely
- Restrict physical and console access to affected systems
🔍 How to Verify
Check if Vulnerable:
Check kernel version and architecture: uname -r and uname -m. If running LoongArch and vulnerable kernel version, system is affected.Check Version:
uname -rVerify Fix Applied:
Verify kernel version includes the fix commits: grep -q '194d26a5a43c26dc98a9b4e2c1d521dcb84dd1bf\|26c0a2d93af55d30a46d5f45d3e9c42cde730168\|8682a71a7f6de7c683f31b4334b04e19685a05f9\|d49ab6857d98266010f3446c9c2063014db5b654' /proc/version📡 Detection & Monitoring
Log Indicators:
- WARNING messages in kernel logs about ktime_get+0xbc/0xc8 during suspend/resume
- Stack traces showing enable_gpe_wakeup() and acpi_enable_all_wakeup_gpes() calls
Network Indicators:
- None - this is a local kernel issue
SIEM Query:
source="kernel" AND "WARNING" AND "ktime_get" AND "suspend"