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authorLinus Torvalds <torvalds@linux-foundation.org>2022-05-08 11:10:17 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-05-08 11:10:17 -0700
commit9692df0581eae29abcc925ca3c12babc6c194741 (patch)
tree098072c4998eb4fe81c83e5300b639c3376e7f7a
parentede4c6d78a32f9b7dfdb12d5edf8c8c4c84c729a (diff)
parent8707898e22fd665bc1d7b18b809be4b56ce25bdd (diff)
Merge tag 'irq-urgent-2022-05-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fix from Thomas Gleixner: "A fix for the threaded interrupt core. A quick sequence of request/free_irq() can result in a hang because the interrupt thread did not reach the thread function and got stopped in the kthread core already. That leaves a state active counter arround which makes a invocation of synchronized_irq() on that interrupt hang forever. Ensure that the thread reached the thread function in request_irq() to prevent that" * tag 'irq-urgent-2022-05-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: genirq: Synchronize interrupt thread startup
-rw-r--r--kernel/irq/internals.h2
-rw-r--r--kernel/irq/irqdesc.c2
-rw-r--r--kernel/irq/manage.c39
3 files changed, 33 insertions, 10 deletions
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index 99cbdf55a8bd..f09c60393e55 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -29,12 +29,14 @@ extern struct irqaction chained_action;
* IRQTF_WARNED - warning "IRQ_WAKE_THREAD w/o thread_fn" has been printed
* IRQTF_AFFINITY - irq thread is requested to adjust affinity
* IRQTF_FORCED_THREAD - irq action is force threaded
+ * IRQTF_READY - signals that irq thread is ready
*/
enum {
IRQTF_RUNTHREAD,
IRQTF_WARNED,
IRQTF_AFFINITY,
IRQTF_FORCED_THREAD,
+ IRQTF_READY,
};
/*
diff --git a/kernel/irq/irqdesc.c b/kernel/irq/irqdesc.c
index 939d21cd55c3..0099b87dd853 100644
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -407,6 +407,7 @@ static struct irq_desc *alloc_desc(int irq, int node, unsigned int flags,
lockdep_set_class(&desc->lock, &irq_desc_lock_class);
mutex_init(&desc->request_mutex);
init_rcu_head(&desc->rcu);
+ init_waitqueue_head(&desc->wait_for_threads);
desc_set_defaults(irq, desc, node, affinity, owner);
irqd_set(&desc->irq_data, flags);
@@ -575,6 +576,7 @@ int __init early_irq_init(void)
raw_spin_lock_init(&desc[i].lock);
lockdep_set_class(&desc[i].lock, &irq_desc_lock_class);
mutex_init(&desc[i].request_mutex);
+ init_waitqueue_head(&desc[i].wait_for_threads);
desc_set_defaults(i, &desc[i], node, NULL, NULL);
}
return arch_early_irq_init();
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index c03f71d5ec10..e3e245a4fd70 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1249,6 +1249,31 @@ static void irq_wake_secondary(struct irq_desc *desc, struct irqaction *action)
}
/*
+ * Internal function to notify that a interrupt thread is ready.
+ */
+static void irq_thread_set_ready(struct irq_desc *desc,
+ struct irqaction *action)
+{
+ set_bit(IRQTF_READY, &action->thread_flags);
+ wake_up(&desc->wait_for_threads);
+}
+
+/*
+ * Internal function to wake up a interrupt thread and wait until it is
+ * ready.
+ */
+static void wake_up_and_wait_for_irq_thread_ready(struct irq_desc *desc,
+ struct irqaction *action)
+{
+ if (!action || !action->thread)
+ return;
+
+ wake_up_process(action->thread);
+ wait_event(desc->wait_for_threads,
+ test_bit(IRQTF_READY, &action->thread_flags));
+}
+
+/*
* Interrupt handler thread
*/
static int irq_thread(void *data)
@@ -1259,6 +1284,8 @@ static int irq_thread(void *data)
irqreturn_t (*handler_fn)(struct irq_desc *desc,
struct irqaction *action);
+ irq_thread_set_ready(desc, action);
+
sched_set_fifo(current);
if (force_irqthreads() && test_bit(IRQTF_FORCED_THREAD,
@@ -1683,8 +1710,6 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
}
if (!shared) {
- init_waitqueue_head(&desc->wait_for_threads);
-
/* Setup the type (level, edge polarity) if configured: */
if (new->flags & IRQF_TRIGGER_MASK) {
ret = __irq_set_trigger(desc,
@@ -1780,14 +1805,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
irq_setup_timings(desc, new);
- /*
- * Strictly no need to wake it up, but hung_task complains
- * when no hard interrupt wakes the thread up.
- */
- if (new->thread)
- wake_up_process(new->thread);
- if (new->secondary)
- wake_up_process(new->secondary->thread);
+ wake_up_and_wait_for_irq_thread_ready(desc, new);
+ wake_up_and_wait_for_irq_thread_ready(desc, new->secondary);
register_irq_proc(irq, desc);
new->dir = NULL;