Bug 2463265 (CVE-2026-31689)

Summary: CVE-2026-31689 kernel: EDAC/mc: Fix error path ordering in edac_mc_alloc()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the EDAC/mc module of the Linux kernel. An error in the ordering of operations within the `edac_mc_alloc` function can lead to a situation where a device's release function is called before the device is fully initialized. This improper initialization can result in a kernel warning and potential system instability, leading to a denial of service.
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Description OSIDB Bzimport 2026-04-27 18:30:57 UTC 
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.
Comment 1 Keith Grant 2026-04-27 22:18:01 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026042757-CVE-2026-31689-9a00@gregkh/T