This is a note to let you know that I've just added the patch titled

target: Fix quiese during transport_write_pending_qf endless loop

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: target-fix-quiese-during-transport_write_pending_qf-endless-loop.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 9574a497df2bbc0a676b609ce0dd24d237cee3a6 Mon Sep 17 00:00:00 2001

From: Nicholas Bellinger nab@linux-iscsi.org Date: Fri, 29 Sep 2017 16:43:11 -0700 Subject: target: Fix quiese during transport_write_pending_qf endless loop

From: Nicholas Bellinger nab@linux-iscsi.org

commit 9574a497df2bbc0a676b609ce0dd24d237cee3a6 upstream.

This patch fixes a potential end-less loop during QUEUE_FULL, where cmd->se_tfo->write_pending() callback fails repeatedly but __transport_wait_for_tasks() has already been invoked to quiese the outstanding se_cmd descriptor.

To address this bug, this patch adds a CMD_T_STOP|CMD_T_ABORTED check within transport_write_pending_qf() and invokes the existing se_cmd->t_transport_stop_comp to signal quiese completion back to __transport_wait_for_tasks().

Cc: Mike Christie mchristi@redhat.com Cc: Hannes Reinecke hare@suse.com Cc: Bryant G. Ly bryantly@linux.vnet.ibm.com Cc: Michael Cyr mikecyr@linux.vnet.ibm.com Cc: Potnuri Bharat Teja bharat@chelsio.com Cc: Sagi Grimberg sagi@grimberg.me Signed-off-by: Nicholas Bellinger nab@linux-iscsi.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- drivers/target/target_core_transport.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)

--- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -2575,7 +2575,20 @@ EXPORT_SYMBOL(transport_generic_new_cmd)

static void transport_write_pending_qf(struct se_cmd *cmd) { + unsigned long flags; int ret; + bool stop; + + spin_lock_irqsave(&cmd->t_state_lock, flags); + stop = (cmd->transport_state & (CMD_T_STOP | CMD_T_ABORTED)); + spin_unlock_irqrestore(&cmd->t_state_lock, flags); + + if (stop) { + pr_debug("%s:%d CMD_T_STOP|CMD_T_ABORTED for ITT: 0x%08llx\n", + __func__, __LINE__, cmd->tag); + complete_all(&cmd->t_transport_stop_comp); + return; + }

ret = cmd->se_tfo->write_pending(cmd); if (ret) {

Patches currently in stable-queue which might be from nab@linux-iscsi.org are

queue-4.14/target-fix-null-pointer-regression-in-core_tmr_drain_tmr_list.patch queue-4.14/iscsi-target-make-task_reassign-use-proper-se_cmd-cmd_kref.patch queue-4.14/target-fix-queue_full-scsi-task-attribute-handling.patch queue-4.14/target-fix-buffer-offset-in-core_scsi3_pri_read_full_status.patch queue-4.14/iscsi-target-fix-non-immediate-tmr-reference-leak.patch queue-4.14/target-fix-caw_sem-leak-in-transport_generic_request_failure.patch queue-4.14/target-avoid-early-cmd_t_pre_execute-failures-during-abort_task.patch queue-4.14/target-fix-quiese-during-transport_write_pending_qf-endless-loop.patch