CVE-2026-74379dax/kmem: account for partial discontiguous resource upon removal

Official description

In the Linux kernel, the following vulnerability has been resolved: dax/kmem: account for partial discontiguous resource upon removal When dev_dax_kmem_probe() partially succeeds (at least one range is mapped) but a subsequent range fails request_mem_region() or add_memory_driver_managed(), the probe silently continues, ultimately returning success, but with the corresponding range resource NULL'ed out. dev_dax_kmem_remove() iterates over all dax_device ranges regardless of if the underlying resource exists. When remove_memory() is called later, it returns 0 because the memory was never added which causes dev_dax_kmem_remove() to incorrectly assume the (nonexistent) resource can be removed and attempts cleanup on a NULL pointer. Fix this by skipping these ranges altogether, noting that these cases are considered success, such that the cleanup is still reached when all actually-added ranges are successfully removed.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/ef4fc53898bd6c4d0119cc6d419ebef7f2560f31
• https://git.kernel.org/stable/c/5d3139abb9d1671fa5e42c3d6d8cb3b05479c5bb
• https://git.kernel.org/stable/c/d47b0b8a69a13e06afafa54723f3e8c99b0c788f
• https://git.kernel.org/stable/c/799e54c510a03a65a57627018a817838d72f35bd
• https://git.kernel.org/stable/c/598ed7393a639c7547b28ff3e14db9f1ac37c132
• https://git.kernel.org/stable/c/30ea97affbcce236c57287c82dc6ef7a29c63b76
• https://git.kernel.org/stable/c/8aa442cfce79e2d69e72fc8e0c0864ac2971149d