This is a note to let you know that I've just added the patch titled
IB/hfi1: Prevent kernel QP post send hard lockups
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ib-hfi1-prevent-kernel-qp-post-send-hard-lockups.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From b6eac931b9bb2bce4db7032c35b41e5e34ec22a5 Mon Sep 17 00:00:00 2001
From: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx>
Date: Sun, 9 Apr 2017 10:16:35 -0700
Subject: IB/hfi1: Prevent kernel QP post send hard lockups
From: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx>
commit b6eac931b9bb2bce4db7032c35b41e5e34ec22a5 upstream.
The driver progress routines can call cond_resched() when
a timeslice is exhausted and irqs are enabled.
If the ULP had been holding a spin lock without disabling irqs and
the post send directly called the progress routine, the cond_resched()
could yield allowing another thread from the same ULP to deadlock
on that same lock.
Correct by replacing the current hfi1_do_send() calldown with a unique
one for post send and adding an argument to hfi1_do_send() to indicate
that the send engine is running in a thread. If the routine is not
running in a thread, avoid calling cond_resched().
Fixes: Commit 831464ce4b74 ("IB/hfi1: Don't call cond_resched in atomic mode when sending packets")
Reviewed-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@xxxxxxxxx>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/infiniband/hw/hfi1/ruc.c | 26 ++++++++++++++++----------
drivers/infiniband/hw/hfi1/verbs.c | 4 ++--
drivers/infiniband/hw/hfi1/verbs.h | 6 ++++--
3 files changed, 22 insertions(+), 14 deletions(-)
--- a/drivers/infiniband/hw/hfi1/ruc.c
+++ b/drivers/infiniband/hw/hfi1/ruc.c
@@ -1,5 +1,5 @@
/*
- * Copyright(c) 2015, 2016 Intel Corporation.
+ * Copyright(c) 2015 - 2017 Intel Corporation.
*
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
@@ -833,23 +833,29 @@ void hfi1_make_ruc_header(struct rvt_qp
/* when sending, force a reschedule every one of these periods */
#define SEND_RESCHED_TIMEOUT (5 * HZ) /* 5s in jiffies */
+void hfi1_do_send_from_rvt(struct rvt_qp *qp)
+{
+ hfi1_do_send(qp, false);
+}
+
void _hfi1_do_send(struct work_struct *work)
{
struct iowait *wait = container_of(work, struct iowait, iowork);
struct rvt_qp *qp = iowait_to_qp(wait);
- hfi1_do_send(qp);
+ hfi1_do_send(qp, true);
}
/**
* hfi1_do_send - perform a send on a QP
* @work: contains a pointer to the QP
+ * @in_thread: true if in a workqueue thread
*
* Process entries in the send work queue until credit or queue is
* exhausted. Only allow one CPU to send a packet per QP.
* Otherwise, two threads could send packets out of order.
*/
-void hfi1_do_send(struct rvt_qp *qp)
+void hfi1_do_send(struct rvt_qp *qp, bool in_thread)
{
struct hfi1_pkt_state ps;
struct hfi1_qp_priv *priv = qp->priv;
@@ -917,8 +923,10 @@ void hfi1_do_send(struct rvt_qp *qp)
qp->s_hdrwords = 0;
/* allow other tasks to run */
if (unlikely(time_after(jiffies, timeout))) {
- if (workqueue_congested(cpu,
- ps.ppd->hfi1_wq)) {
+ if (!in_thread ||
+ workqueue_congested(
+ cpu,
+ ps.ppd->hfi1_wq)) {
spin_lock_irqsave(
&qp->s_lock,
ps.flags);
@@ -931,11 +939,9 @@ void hfi1_do_send(struct rvt_qp *qp)
*ps.ppd->dd->send_schedule);
return;
}
- if (!irqs_disabled()) {
- cond_resched();
- this_cpu_inc(
- *ps.ppd->dd->send_schedule);
- }
+ cond_resched();
+ this_cpu_inc(
+ *ps.ppd->dd->send_schedule);
timeout = jiffies + (timeout_int) / 8;
}
spin_lock_irqsave(&qp->s_lock, ps.flags);
--- a/drivers/infiniband/hw/hfi1/verbs.c
+++ b/drivers/infiniband/hw/hfi1/verbs.c
@@ -1,5 +1,5 @@
/*
- * Copyright(c) 2015, 2016 Intel Corporation.
+ * Copyright(c) 2015 - 2017 Intel Corporation.
*
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
@@ -1697,7 +1697,7 @@ int hfi1_register_ib_device(struct hfi1_
dd->verbs_dev.rdi.driver_f.qp_priv_free = qp_priv_free;
dd->verbs_dev.rdi.driver_f.free_all_qps = free_all_qps;
dd->verbs_dev.rdi.driver_f.notify_qp_reset = notify_qp_reset;
- dd->verbs_dev.rdi.driver_f.do_send = hfi1_do_send;
+ dd->verbs_dev.rdi.driver_f.do_send = hfi1_do_send_from_rvt;
dd->verbs_dev.rdi.driver_f.schedule_send = hfi1_schedule_send;
dd->verbs_dev.rdi.driver_f.schedule_send_no_lock = _hfi1_schedule_send;
dd->verbs_dev.rdi.driver_f.get_pmtu_from_attr = get_pmtu_from_attr;
--- a/drivers/infiniband/hw/hfi1/verbs.h
+++ b/drivers/infiniband/hw/hfi1/verbs.h
@@ -1,5 +1,5 @@
/*
- * Copyright(c) 2015, 2016 Intel Corporation.
+ * Copyright(c) 2015 - 2017 Intel Corporation.
*
* This file is provided under a dual BSD/GPLv2 license. When using or
* redistributing this file, you may do so under either license.
@@ -372,7 +372,9 @@ void hfi1_make_ruc_header(struct rvt_qp
void _hfi1_do_send(struct work_struct *work);
-void hfi1_do_send(struct rvt_qp *qp);
+void hfi1_do_send_from_rvt(struct rvt_qp *qp);
+
+void hfi1_do_send(struct rvt_qp *qp, bool in_thread);
void hfi1_send_complete(struct rvt_qp *qp, struct rvt_swqe *wqe,
enum ib_wc_status status);
Patches currently in stable-queue which might be from mike.marciniszyn@xxxxxxxxx are
queue-4.9/ib-hfi1-prevent-kernel-qp-post-send-hard-lockups.patch