CVE-2017-18174

What it actually does

Double free vulnerability triggered when amd_gpio_remove calls pinctrl_unregister, freeing kernel memory structures twice and corrupting allocator state.

Why it matters to the business

Kernel memory corruption can cause system crashes, denial of service, or potential arbitrary code execution, disrupting operations on affected Linux systems with AMD GPIO hardware.

How an attack unfolds

An attacker with the ability to trigger device removal or driver unload on an AMD-based system invokes amd_gpio_remove, which calls pinctrl_unregister and performs the double free, leading to memory corruption that may be leveraged for privilege escalation or crashes.

How to fix it

Update the Linux kernel to a version containing commit 251e22abde21833b3d29577e4d8c7aaccd650eee or later; rebuild and deploy the fixed kernel image across all affected systems.

How to confirm the fix worked

Verify the running kernel source contains commit 251e22abde21833b3d29577e4d8c7aaccd650eee, confirm pinctrl-amd.c no longer performs the double-free sequence, and test device removal paths on AMD hardware.

Typical attack path

1. Identify or control an AMD platform running a vulnerable kernel with pinctrl-amd loaded.
2. Trigger amd_gpio_remove via module unload, device hot-unplug, or driver error path.
3. pinctrl_unregister executes and frees resources.
4. Subsequent free in amd_gpio_remove causes double-free corruption.
5. Attacker manipulates freed memory for code execution or causes denial of service.

How to detect it

Review kernel logs for double-free warnings, slab corruption reports, or oops traces referencing pinctrl-amd.c or amd_gpio_remove; inspect for unexpected module unloads or device removal events on AMD platforms.

What your security team should do

• Prioritize kernel upgrades on all AMD-based Linux systems within the next patch cycle.
• Restrict unprivileged module loading and device management capabilities until patched.
• Monitor for kernel oops or panic logs related to pinctrl-amd after applying updates.