Description

In the Linux kernel, the following vulnerability has been resolved: cxl/region: Avoid null pointer dereference in region lookup cxl_dpa_to_region() looks up a region based on a memdev and DPA. It wrongly assumes an endpoint found mapping the DPA is also of a fully assembled region. When not true it leads to a null pointer dereference looking up the region name. This appears during testing of region lookup after a failure to assemble a BIOS defined region or if the lookup raced with the assembly of the BIOS defined region. Failure to clean up BIOS defined regions that fail assembly is an issue in itself and a fix to that problem will alleviate some of the impact. It will not alleviate the race condition so let's harden this path. The behavior change is that the kernel oops due to a null pointer dereference is replaced with a dev_dbg() message noting that an endpoint was mapped. Additional comments are added so that future users of this function can more clearly understand what it provides.

Weaknesses 1

Affected Products 2

References 3

• git.kernel.org https://git.kernel.org/stable/c/285f2a08841432fc3e498b1cd00cce5216cdf189
  Patch
• git.kernel.org https://git.kernel.org/stable/c/a9e099e29e925f8b31cfe53e8a786b9796f8e453
  Patch
• git.kernel.org https://git.kernel.org/stable/c/b8a40a6dbfb0150c1081384caa9bbe28ce5d5060
  Patch

Remediation

• git.kernel.org https://git.kernel.org/stable/c/285f2a08841432fc3e498b1cd00cce5216cdf189
  Patch
• git.kernel.org https://git.kernel.org/stable/c/a9e099e29e925f8b31cfe53e8a786b9796f8e453
  Patch
• git.kernel.org https://git.kernel.org/stable/c/b8a40a6dbfb0150c1081384caa9bbe28ce5d5060
  Patch