From ef4cb70a4c22bf301cd757dcc838dc8ca9526477 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Tue, 2 Mar 2021 18:14:53 +0200 Subject: [PATCH 1/2] genirq/irq_sim: Fix typos in kernel doc (fnode -> fwnode) Fix typos in kernel doc, otherwise validation script complains: .../irq_sim.c:170: warning: Function parameter or member 'fwnode' not described in 'irq_domain_create_sim' .../irq_sim.c:170: warning: Excess function parameter 'fnode' description in 'irq_domain_create_sim' .../irq_sim.c:240: warning: Function parameter or member 'fwnode' not described in 'devm_irq_domain_create_sim' .../irq_sim.c:240: warning: Excess function parameter 'fnode' description in 'devm_irq_domain_create_sim' Signed-off-by: Andy Shevchenko Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20210302161453.28540-1-andriy.shevchenko@linux.intel.com --- kernel/irq/irq_sim.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/irq/irq_sim.c b/kernel/irq/irq_sim.c index 48006608baf0..40880c350b95 100644 --- a/kernel/irq/irq_sim.c +++ b/kernel/irq/irq_sim.c @@ -159,7 +159,7 @@ static const struct irq_domain_ops irq_sim_domain_ops = { * irq_domain_create_sim - Create a new interrupt simulator irq_domain and * allocate a range of dummy interrupts. * - * @fnode: struct fwnode_handle to be associated with this domain. + * @fwnode: struct fwnode_handle to be associated with this domain. * @num_irqs: Number of interrupts to allocate. * * On success: return a new irq_domain object. @@ -228,7 +228,7 @@ static void devm_irq_domain_release_sim(struct device *dev, void *res) * a managed device. * * @dev: Device to initialize the simulator object for. - * @fnode: struct fwnode_handle to be associated with this domain. + * @fwnode: struct fwnode_handle to be associated with this domain. * @num_irqs: Number of interrupts to allocate * * On success: return a new irq_domain object. From 81e2073c175b887398e5bca6c004efa89983f58d Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 17 Mar 2021 15:38:52 +0100 Subject: [PATCH 2/2] genirq: Disable interrupts for force threaded handlers With interrupt force threading all device interrupt handlers are invoked from kernel threads. Contrary to hard interrupt context the invocation only disables bottom halfs, but not interrupts. This was an oversight back then because any code like this will have an issue: thread(irq_A) irq_handler(A) spin_lock(&foo->lock); interrupt(irq_B) irq_handler(B) spin_lock(&foo->lock); This has been triggered with networking (NAPI vs. hrtimers) and console drivers where printk() happens from an interrupt which interrupted the force threaded handler. Now people noticed and started to change the spin_lock() in the handler to spin_lock_irqsave() which affects performance or add IRQF_NOTHREAD to the interrupt request which in turn breaks RT. Fix the root cause and not the symptom and disable interrupts before invoking the force threaded handler which preserves the regular semantics and the usefulness of the interrupt force threading as a general debugging tool. For not RT this is not changing much, except that during the execution of the threaded handler interrupts are delayed until the handler returns. Vs. scheduling and softirq processing there is no difference. For RT kernels there is no issue. Fixes: 8d32a307e4fa ("genirq: Provide forced interrupt threading") Reported-by: Johan Hovold Signed-off-by: Thomas Gleixner Reviewed-by: Johan Hovold Acked-by: Sebastian Andrzej Siewior Link: https://lore.kernel.org/r/20210317143859.513307808@linutronix.de --- kernel/irq/manage.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index dec3f73e8db9..21ea370fccda 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -1142,11 +1142,15 @@ irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action) irqreturn_t ret; local_bh_disable(); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_disable(); ret = action->thread_fn(action->irq, action->dev_id); if (ret == IRQ_HANDLED) atomic_inc(&desc->threads_handled); irq_finalize_oneshot(desc, action); + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) + local_irq_enable(); local_bh_enable(); return ret; }