A recently patched vulnerability in the Linux kernel, CVE-2024-53134, could trigger kernel panics on impacted systems. The flaw resides in the imx93-blk-ctrl Power Management Domain driver, which is specific to some NXP i.MX93 embedded devices.

In this post, you'll learn what caused the bug, how it impacts systems, see the vulnerable code, the fixed code, and where to read the official patch. Simple explanations and actionable advice included.

The Root Cause

In the kernel driver responsible for disconnecting power domains on i.MX93 platforms, the code tried to loop through the number of domains, but used the wrong condition:

for (i = ; bc->onecell_data.num_domains; i++)

It should have been

for (i = ; i < bc->onecell_data.num_domains; i++)

This means the loop never ends, eventually exhausting system resources and causing a panic.

Why Is This Dangerous?

Whenever you remove the imx93-blk-ctrl driver (for example, during a device shutdown, unload, or reboot sequence), the driver could hang.

Services and applications relying on proper power management may never finish.

- In certain use cases, this could be exploited to crash the system remotely or locally, denying service.

Here’s the relevant section from the vulnerable driver

static int imx93_blk_ctrl_remove(struct platform_device *pdev)
{
    struct imx93_blk_ctrl *bc = platform_get_drvdata(pdev);
    int i;

    for (i = ; bc->onecell_data.num_domains; i++)
        pm_genpd_remove(bc->genpd_data.domains[i]);
    ...
}

Notice the faulty loop condition: it doesn’t use the iterator.

The corrected logic, as per the official kernel patch, is

for (i = ; i < bc->onecell_data.num_domains; i++)
    pm_genpd_remove(bc->genpd_data.domains[i]);

Also, to address the log warning

> "imx93-blk-ctrl 4ac10000.system-controller: Unbalanced pm_runtime_enable!"

The fix disables runtime PM during removal

pm_runtime_disable(&pdev->dev);

Exploiting CVE-2024-53134

It’s a denial of service bug, not an RCE or privilege escalation.

Exploit scenario:
An untrusted user (or malicious script) with the ability to manage kernel modules could rmmod the impacted module. If exploit code keeps removing and re-inserting the module, they can reliably hang the system.

Sample exploit command line

sudo rmmod imx93_blk_ctrl

On affected systems, the kernel would freeze or panic, requiring a power reset.

References and Patches

- Upstream Fix Commit
- NXP i.MX93 Documentation
- Kernel Power Domain Subsystem

Upgrade to a patched kernel: Make sure your kernel includes the fix from June 2024 or later.

- Restrict module management: Only root or trusted users should be able to load or unload kernel modules.

Monitor logs: Look for suspicious activity or Unbalanced pm_runtime_enable warnings.

- Test your hardware: If using an i.MX93 platform, perform removal of the driver and ensure no hangs occur.

Conclusion

CVE-2024-53134 highlights how a single typo can bring down embedded Linux systems. If your devices use the NXP i.MX93 series, double-check your kernel version and apply upgrades promptly. For general users, this bug is a reminder that kernel integrity is critical—automatic updates and strong security policies can prevent a simple loop from turning into a system-wide headache.

Stay safe!

If you want more technical updates like this, follow kernel.org and your hardware vendor’s security advisories.

Timeline

Published on: 12/04/2024 15:15:13 UTC
Last modified on: 12/11/2024 17:10:16 UTC