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

ksmbd: fix race condition between session lookup and expire

 Thread A                        +  Thread B
 ksmbd_session_lookup            |  smb2_sess_setup
   sess = xa_load                |
                                 |
                                 |    xa_erase(&conn->sessions, sess->id);
                                 |
                                 |    ksmbd_session_destroy(sess) --> kfree(sess)
                                 |
   // UAF!                       |
   sess->last_active = jiffies   |
                                 +

This patch add rwsem to fix race condition between ksmbd_session_lookup
and ksmbd_expire_session.

References:
http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2023-52480
https://www.cve.org/CVERecord?id=CVE-2023-52480
https://git.kernel.org/stable/c/18ced78b0ebccc2d16f426143dc56ab3aad666be
https://git.kernel.org/stable/c/53ff5cf89142b978b1a5ca8dc4d4425e6a09745f
https://git.kernel.org/stable/c/a2ca5fd3dbcc665e1169044fa0c9e3eba779202b
https://git.kernel.org/stable/c/c77fd3e25a51ac92b0f1b347a96eff6a0b4f066f