CVE-2026-23193: Use After Free

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

scsi: target: iscsi: Fix use-after-free in iscsit_dec_session_usage_count()

In iscsit_dec_session_usage_count(), the function calls complete() while holding the sess->session_usage_lock. Similar to the connection usage count logic, the waiter signaled by complete() (e.g., in the session release path) may wake up and free the iscsit_session structure immediately.

This creates a race condition where the current thread may attempt to execute spin_unlock_bh() on a session structure that has already been deallocated, resulting in a KASAN slab-use-after-free.

To resolve this, release the session_usage_lock before calling complete() to ensure all dereferences of the sess pointer are finished before the waiter is allowed to proceed with deallocation.