Dear RT folks!
I'm pleased to announce the v4.8.14-rt9 patch set.
Changes since v4.8.14-rt8:
- If a network interface is removed we move all skbs which are active to
a list and free it later. The hunk where the list was cleaned up was
lost and is back.
- bnx2x and a few others could corrupt their ->poll_list. Patch by
Steven Rostedt.
- A missing RCU section in the workqueue code could lead to a "use after
free" condition if the workqueue was removed. Reported by John Keeping.
Known issues
- CPU hotplug got a little better but can deadlock.
The delta patch against v4.8.14-rt9 is appended below and can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.8/incr/patch-4.8.14-rt8-rt9.patch.xz
You can get this release via the git tree at:
git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git v4.8.14-rt9
The RT patch against v4.8.14 can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.8/patch-4.8.14-rt9.patch.xz
The split quilt queue is available at:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/4.8/patches-4.8.14-rt9.tar.xz
Sebastian
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -395,7 +395,19 @@ typedef enum rx_handler_result rx_handler_result_t;
typedef rx_handler_result_t rx_handler_func_t(struct sk_buff **pskb);
void __napi_schedule(struct napi_struct *n);
+
+/*
+ * When PREEMPT_RT_FULL is defined, all device interrupt handlers
+ * run as threads, and they can also be preempted (without PREEMPT_RT
+ * interrupt threads can not be preempted). Which means that calling
+ * __napi_schedule_irqoff() from an interrupt handler can be preempted
+ * and can corrupt the napi->poll_list.
+ */
+#ifdef CONFIG_PREEMPT_RT_FULL
+#define __napi_schedule_irqoff(n) __napi_schedule(n)
+#else
void __napi_schedule_irqoff(struct napi_struct *n);
+#endif
static inline bool napi_disable_pending(struct napi_struct *n)
{
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1127,9 +1127,11 @@ static void put_pwq_unlocked(struct pool_workqueue *pwq)
* As both pwqs and pools are RCU protected, the
* following lock operations are safe.
*/
+ rcu_read_lock();
local_spin_lock_irq(pendingb_lock, &pwq->pool->lock);
put_pwq(pwq);
local_spin_unlock_irq(pendingb_lock, &pwq->pool->lock);
+ rcu_read_unlock();
}
}
diff --git a/localversion-rt b/localversion-rt
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt8
+-rt9
diff --git a/net/core/dev.c b/net/core/dev.c
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4912,6 +4912,7 @@ void __napi_schedule(struct napi_struct *n)
}
EXPORT_SYMBOL(__napi_schedule);
+#ifndef CONFIG_PREEMPT_RT_FULL
/**
* __napi_schedule_irqoff - schedule for receive
* @n: entry to schedule
@@ -4923,6 +4924,7 @@ void __napi_schedule_irqoff(struct napi_struct *n)
____napi_schedule(this_cpu_ptr(&softnet_data), n);
}
EXPORT_SYMBOL(__napi_schedule_irqoff);
+#endif
void __napi_complete(struct napi_struct *n)
{
@@ -5212,13 +5214,21 @@ static void net_rx_action(struct softirq_action *h)
struct softnet_data *sd = this_cpu_ptr(&softnet_data);
unsigned long time_limit = jiffies + 2;
int budget = netdev_budget;
+ struct sk_buff_head tofree_q;
+ struct sk_buff *skb;
LIST_HEAD(list);
LIST_HEAD(repoll);
+ __skb_queue_head_init(&tofree_q);
+
local_irq_disable();
+ skb_queue_splice_init(&sd->tofree_queue, &tofree_q);
list_splice_init(&sd->poll_list, &list);
local_irq_enable();
+ while ((skb = __skb_dequeue(&tofree_q)))
+ kfree_skb(skb);
+
for (;;) {
struct napi_struct *n;
--
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