4.14-stable review patch. If anyone has any objections, please let me know.
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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) {