CVE-2026-90151NFSv4: remove callback IDR entry on client allocation failure

Official description

In the Linux kernel, the following vulnerability has been resolved: NFSv4: remove callback IDR entry on client allocation failure nfs4_alloc_client() allocates an NFSv4.0 callback identifier before it finishes setting up the client. If any later initialization step fails, the error path frees the nfs_client directly with nfs_free_client(). That bypasses nfs_put_client(), which is where the callback IDR entry is removed during normal teardown. A failed allocation can therefore leave cb_ident_idr pointing at a freed nfs_client. A later NFSv4.0 callback lookup by cb_ident 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.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/68c721391b761dbe38d5b0094d2bb6e8489ad92b
• https://git.kernel.org/stable/c/9bfdd0f591307b5198826a0e7a5b2f35f87acd2d
• https://git.kernel.org/stable/c/7c4812eb96bdcafb31a65b12f2aa96659429d1d4
• https://git.kernel.org/stable/c/fc95ca82d5ae598c428ab5a00ae69f8526d59371
• https://git.kernel.org/stable/c/80b1c3d5a881f7d9081aa9f46da9742878a0f893
• https://git.kernel.org/stable/c/3f2387e8bfbc4efda5d77c3a11a028d0a119c48f
• https://git.kernel.org/stable/c/5891c03e150920618db0e9c4ea2d772abacdcfd1
• https://git.kernel.org/stable/c/d05c2007b3d84ccba11dc6e9cb3202768cc72f14