CVE-2026-90164smb/server: abort initialization when proc setup fails

Official description

In the Linux kernel, the following vulnerability has been resolved: smb/server: abort initialization when proc setup fails ksmbd_server_init() calls ksmbd_proc_init() before creating the remaining proc entries and server subsystems. ksmbd_proc_init() tears down partial state on a procfs or percpu_counter allocation failure, but returns void, so ksmbd_server_init() continues as if the counters were usable. Once userspace starts the server, server_ctrl_handle_init() calls ksmbd_proc_reset(), which reaches percpu_counter_set() with a NULL per-CPU counters pointer on SMP systems. The later ksmbd_proc_create() calls also receive a NULL parent and may create entries in the /proc root; ksmbd_proc_cleanup() cannot remove those entries because ksmbd_proc_fs is NULL.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/fb4ba2bdfc1de8866e7c8e00df99f4b03ff42f09
• https://git.kernel.org/stable/c/db97f3763727d652112ae70038d4e17b3ce277bb