CVE-2025-71072

/// Technical description

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

shmem: fix recovery on rename failures

maple_tree insertions can fail if we are seriously short on memory;

simple_offset_rename() does not recover well if it runs into that.

The same goes for simple_offset_rename_exchange().

Moreover, shmem_whiteout() expects that if it succeeds, the caller will

progress to d_move(), i.e. that shmem_rename2() won't fail past the

successful call of shmem_whiteout().

Not hard to fix, fortunately - mtree_store() can't fail if the index we

are trying to store into is already present in the tree as a singleton.

For simple_offset_rename_exchange() that's enough - we just need to be

careful about the order of operations.

For simple_offset_rename() solution is to preinsert the target into the

tree for new_dir; the rest can be done without any potentially failing

operations.

That preinsertion has to be done in shmem_rename2() rather than in

simple_offset_rename() itself - otherwise we'd

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References