CVE-2026-90151

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

NFSv4: remove callback IDR entry on client allocation failure

nfs4allocclient() allocates an NFSv4.0 callback identifier before it

finishes setting up the client. If any later initialization step fails,

the error path frees the nfsclient directly with nfsfree_client(). That

bypasses nfsputclient(), which is where the callback IDR entry is

removed during normal teardown.

A failed allocation can therefore leave cbidentidr pointing at a freed

nfsclient. A later NFSv4.0 callback lookup by cbident would find the

stale pointer and take a reference to it.

Make the callback IDR removal helper callable by the allocation failure

path, and remove the callback identifier before freeing the client.

This was found by a local static-analysis checker for publish-before-free

lifetime bugs and confirmed by manual inspection.