TLDRVuln - Cybersecurity Vulnerabilities Made Simple

In the Linux kernel, the following vulnerability has been resolved:

EDAC/mc: Fix error path ordering in edac_mc_alloc()

When the mci->pvt_info allocation in edac_mc_alloc() fails, the error path

will call put_device() which will end up calling the device's release

function.

However, the init ordering is wrong such that device_initialize() happens

*after* the failed allocation and thus the device itself and the release

function pointer are not initialized yet when they're called:

MCE: In-kernel MCE decoding enabled.

------------[ cut here ]------------

kobject: '(null)': is not initialized, yet kobject_put() is being called.

WARNING: lib/kobject.c:734 at kobject_put, CPU#22: systemd-udevd

CPU: 22 UID: 0 PID: 538 Comm: systemd-udevd Not tainted 7.0.0-rc1+ #2 PREEMPT(full)

RIP: 0010:kobject_put

Call Trace:

<TASK>

edac_mc_alloc+0xbe/0xe0 [edac_core]

amd64_edac_init+0x7a4/0xff0 [amd64_edac]

? __pfx_amd64_edac_init+0x10/0x10 [amd64_edac]

do_one_initcall

...

Reorder the calling sequence so that the device is initialized and thus the

release function pointer is properly set before it can be used.

This was found by Claude while reviewing another EDAC patch.