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author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-08 11:10:17 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-05-08 11:10:17 -0700 |
commit | 9692df0581eae29abcc925ca3c12babc6c194741 (patch) | |
tree | 098072c4998eb4fe81c83e5300b639c3376e7f7a /kernel | |
parent | ede4c6d78a32f9b7dfdb12d5edf8c8c4c84c729a (diff) | |
parent | 8707898e22fd665bc1d7b18b809be4b56ce25bdd (diff) | |
download | linux-9692df0581eae29abcc925ca3c12babc6c194741.tar.bz2 |
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
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/irq/internals.h | 2 | ||||
-rw-r--r-- | kernel/irq/irqdesc.c | 2 | ||||
-rw-r--r-- | kernel/irq/manage.c | 39 |
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; |