3.16.7-ckt26 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> commit a6d9bb1c9605cd4f44e2d8290dc4d0e88f20292d upstream. This patch fixes a NULL pointer se_cmd->cmd_kref < 0 refcount bug during TMR LUN_RESET with active TMRs, triggered during se_cmd + se_tmr_req descriptor shutdown + release via core_tmr_drain_tmr_list(). To address this bug, go ahead and obtain a local kref_get_unless_zero(&se_cmd->cmd_kref) for active I/O to set CMD_T_ABORTED, and transport_wait_for_tasks() followed by the final target_put_sess_cmd() to drop the local ->cmd_kref. Also add two new checks within target_tmr_work() to avoid CMD_T_ABORTED -> TFO->queue_tm_rsp() callbacks ahead of invoking the backend -> fabric put in transport_cmd_check_stop_to_fabric(). For good measure, also change core_tmr_release_req() to use list_del_init() ahead of se_tmr_req memory free. Reviewed-by: Quinn Tran <quinn.tran@xxxxxxxxxx> Cc: Himanshu Madhani <himanshu.madhani@xxxxxxxxxx> Cc: Sagi Grimberg <sagig@xxxxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: Hannes Reinecke <hare@xxxxxxx> Cc: Andy Grover <agrover@xxxxxxxxxx> Cc: Mike Christie <mchristi@xxxxxxxxxx> Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx> [ luis: backported to 3.16: used Nicholas' backport to 3.14 ] Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx> --- drivers/target/target_core_tmr.c | 22 +++++++++++++++++++++- drivers/target/target_core_transport.c | 17 +++++++++++++++++ 2 files changed, 38 insertions(+), 1 deletion(-) diff --git a/drivers/target/target_core_tmr.c b/drivers/target/target_core_tmr.c index f7cd95e8111a..1b74be036149 100644 --- a/drivers/target/target_core_tmr.c +++ b/drivers/target/target_core_tmr.c @@ -76,7 +76,7 @@ void core_tmr_release_req( } spin_lock_irqsave(&dev->se_tmr_lock, flags); - list_del(&tmr->tmr_list); + list_del_init(&tmr->tmr_list); spin_unlock_irqrestore(&dev->se_tmr_lock, flags); kfree(tmr); @@ -181,9 +181,11 @@ static void core_tmr_drain_tmr_list( struct list_head *preempt_and_abort_list) { LIST_HEAD(drain_tmr_list); + struct se_session *sess; struct se_tmr_req *tmr_p, *tmr_pp; struct se_cmd *cmd; unsigned long flags; + bool rc; /* * Release all pending and outgoing TMRs aside from the received * LUN_RESET tmr.. @@ -209,17 +211,31 @@ static void core_tmr_drain_tmr_list( if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd)) continue; + sess = cmd->se_sess; + if (WARN_ON_ONCE(!sess)) + continue; + + spin_lock(&sess->sess_cmd_lock); spin_lock(&cmd->t_state_lock); if (!(cmd->transport_state & CMD_T_ACTIVE)) { spin_unlock(&cmd->t_state_lock); + spin_unlock(&sess->sess_cmd_lock); continue; } if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) { spin_unlock(&cmd->t_state_lock); + spin_unlock(&sess->sess_cmd_lock); continue; } + cmd->transport_state |= CMD_T_ABORTED; spin_unlock(&cmd->t_state_lock); + rc = kref_get_unless_zero(&cmd->cmd_kref); + spin_unlock(&sess->sess_cmd_lock); + if (!rc) { + printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n"); + continue; + } list_move_tail(&tmr_p->tmr_list, &drain_tmr_list); } spin_unlock_irqrestore(&dev->se_tmr_lock, flags); @@ -233,7 +249,11 @@ static void core_tmr_drain_tmr_list( (preempt_and_abort_list) ? "Preempt" : "", tmr_p, tmr_p->function, tmr_p->response, cmd->t_state); + cancel_work_sync(&cmd->work); + transport_wait_for_tasks(cmd); + transport_cmd_finish_abort(cmd, 1); + target_put_sess_cmd(cmd->se_sess, cmd); } } diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 9eeeb78bf604..4e0b86685369 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -2951,8 +2951,17 @@ static void target_tmr_work(struct work_struct *work) struct se_cmd *cmd = container_of(work, struct se_cmd, work); struct se_device *dev = cmd->se_dev; struct se_tmr_req *tmr = cmd->se_tmr_req; + unsigned long flags; int ret; + spin_lock_irqsave(&cmd->t_state_lock, flags); + if (cmd->transport_state & CMD_T_ABORTED) { + tmr->response = TMR_FUNCTION_REJECTED; + spin_unlock_irqrestore(&cmd->t_state_lock, flags); + goto check_stop; + } + spin_unlock_irqrestore(&cmd->t_state_lock, flags); + switch (tmr->function) { case TMR_ABORT_TASK: core_tmr_abort_task(dev, tmr, cmd->se_sess); @@ -2980,9 +2989,17 @@ static void target_tmr_work(struct work_struct *work) break; } + spin_lock_irqsave(&cmd->t_state_lock, flags); + if (cmd->transport_state & CMD_T_ABORTED) { + spin_unlock_irqrestore(&cmd->t_state_lock, flags); + goto check_stop; + } cmd->t_state = TRANSPORT_ISTATE_PROCESSING; + spin_unlock_irqrestore(&cmd->t_state_lock, flags); + cmd->se_tfo->queue_tm_rsp(cmd); +check_stop: transport_cmd_check_stop_to_fabric(cmd); } -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html