From mboxrd@z Thu Jan 1 00:00:00 1970 From: sboyd@codeaurora.org (Stephen Boyd) Date: Mon, 04 Aug 2014 16:22:39 -0700 Subject: [PATCH] irqchip: gic: Allow gic_arch_extn hooks to call into scheduler In-Reply-To: References: <1407191616-31829-1-git-send-email-sboyd@codeaurora.org> Message-ID: <53E015BF.4060701@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 08/04/14 16:20, Nicolas Pitre wrote: > On Mon, 4 Aug 2014, Stephen Boyd wrote: > >> diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c >> index 7c131cf7cc13..824c1e2ac403 100644 >> --- a/drivers/irqchip/irq-gic.c >> +++ b/drivers/irqchip/irq-gic.c >> @@ -72,6 +72,8 @@ struct gic_chip_data { >> }; >> >> static DEFINE_RAW_SPINLOCK(irq_controller_lock); >> +/* Synchronize switching CPU interface and sending SGIs */ >> +static DEFINE_RAW_SPINLOCK(gic_sgi_lock); > I'd suggest moving this below gic_cpu_map[] definition for the comment > block right above it to also apply to this lock. Ok. > >> >> /* >> * The GIC mapping of CPU interfaces does not necessarily match >> @@ -658,7 +660,7 @@ static void gic_raise_softirq(const struct cpumask *mask, unsigned int irq) >> int cpu; >> unsigned long flags, map = 0; >> >> - raw_spin_lock_irqsave(&irq_controller_lock, flags); >> + raw_spin_lock_irqsave(&gic_sgi_lock, flags); >> >> /* Convert our logical CPU mask into a physical one. */ >> for_each_cpu(cpu, mask) >> @@ -673,7 +675,7 @@ static void gic_raise_softirq(const struct cpumask *mask, unsigned int irq) >> /* this always happens on GIC0 */ >> writel_relaxed(map << 16 | irq, gic_data_dist_base(&gic_data[0]) + GIC_DIST_SOFTINT); >> >> - raw_spin_unlock_irqrestore(&irq_controller_lock, flags); >> + raw_spin_unlock_irqrestore(&gic_sgi_lock, flags); >> } >> #endif >> >> @@ -742,6 +744,7 @@ void gic_migrate_target(unsigned int new_cpu_id) >> cur_target_mask = 0x01010101 << cur_cpu_id; >> ror_val = (cur_cpu_id - new_cpu_id) & 31; >> >> + raw_spin_lock(&gic_sgi_lock); >> raw_spin_lock(&irq_controller_lock); > According to your call trace, you would now take irq_controller_lock and > then gic_sgi_lock. Here you're doing it in the opposite order with an > AB-BA deadlock potential. I'd suggest reversing them here. > Ah thanks. I guess I didn't see it on lockdep because this code never runs. Actually I don't think we need to hold it across this piece of code at all. See v2. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation