4.8-stable review patch. If anyone has any objections, please let me know.
------------------ From: Nicholas Bellinger <[email protected]> commit 527268df31e57cf2b6d417198717c6d6afdb1e3e upstream. This patch fixes a regression in >= v4.1.y code where the original SCF_ACK_KREF assignment in target_get_sess_cmd() was dropped upstream in commit 054922bb, but the series for addressing TMR ABORT_TASK + LUN_RESET with fabric session reinstatement in commit febe562c20 still depends on this code in transport_cmd_finish_abort(). The regression manifests itself as a se_cmd->cmd_kref +1 leak, where ABORT_TASK + LUN_RESET can hang indefinately for a specific I_T session for drivers using SCF_ACK_KREF, resulting in hung kthreads. This patch has been verified with v4.1.y code. Reported-by: Vaibhav Tandon <[email protected]> Tested-by: Vaibhav Tandon <[email protected]> Cc: Vaibhav Tandon <[email protected]> Signed-off-by: Nicholas Bellinger <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/target/target_core_transport.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -2547,8 +2547,10 @@ int target_get_sess_cmd(struct se_cmd *s * fabric acknowledgement that requires two target_put_sess_cmd() * invocations before se_cmd descriptor release. */ - if (ack_kref) + if (ack_kref) { kref_get(&se_cmd->cmd_kref); + se_cmd->se_cmd_flags |= SCF_ACK_KREF; + } spin_lock_irqsave(&se_sess->sess_cmd_lock, flags); if (se_sess->sess_tearing_down) {
