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.

Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Reported-by: Zhaojuan Guo <zguo@redhat.com>
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Link: https://patch.msgid.link/20260112165352.138606-3-mlombard@redhat.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

0 files changed, 0 insertions, 0 deletions