Scenario: * A DYNAMIC/OSMOCOM TS in PDCH mode is selected to be used for TCH/F, hence the TS is being switched to TCH/F: RF Channel Release is being transmitted and waiting to receive RF Channel release ACK. Hence, lchan is in state LCHAN_ST_WAIT_TS_READY, and there's a conn with an assignment FSM pointing to it in conn->assignment.new_lchan. lchan->conn also points to the related conn. * The BSSMAP SCCP link goes down (link lost), which will terminate the conn->fi of all conns related to the MSC peer going down. During that teardown, first gscon_pre_term()->gscon_release_lchans()-> assignment_reset() is called, which sets conn->assignment.new_lchan=NULL and calls lchan_release(). This path leaves conn->assignment.new_lchan->conn untouched! * Later in the call path, when finally the bsc_subscr is put() to 0 references and associated lchan gets its lchan_forget_conn() called, it will access lchan->conn which was not freed in the previous step mentioned above during assignment_reset().
This patch fixes the issue by adding a lchan_forget_conn() after the lchan_release() in assignment_reset(), to make sure the conn is no longer user by the lchan afterwards.
Related: OS#6936 Change-Id: Ifbb9a61cd8a40d953ef5c2b52f9be9ef0dffefa4 (cherry picked from commit 44efd5b20b50ab894ed32ada3340fb5507b4852b)
Scenario: * A DYNAMIC/OSMOCOM TS in PDCH mode is selected to be used for TCH/F, hence the TS is being switched to TCH/F: RF Channel Release is being transmitted and waiting to receive RF Channel release ACK. Hence, lchan is in state LCHAN_ST_WAIT_TS_READY, and there's a conn with an assignment FSM pointing to it in conn->assignment.new_lchan. lchan->conn also points to the related conn. * The BSSMAP SCCP link goes down (link lost), which will terminate the conn->fi of all conns related to the MSC peer going down. During that teardown, first gscon_pre_term()->gscon_release_lchans()-> assignment_reset() is called, which sets conn->assignment.new_lchan=NULL and calls lchan_release(). This path leaves conn->assignment.new_lchan->conn untouched! * Later in the call path, when finally the bsc_subscr is put() to 0 references and associated lchan gets its lchan_forget_conn() called, it will access lchan->conn which was not freed in the previous step mentioned above during assignment_reset().
This patch fixes the issue by adding a lchan_forget_conn() after the lchan_release() in assignment_reset(), to make sure the conn is no longer user by the lchan afterwards.
