From 1fee9db9b42d821e8007289d4eea74bdf85b1543 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 6 Jul 2021 11:38:59 +0100 Subject: irqchip/mips: Fix RCU violation when using irqdomain lookup on interrupt entry Since d4a45c68dc81 ("irqdomain: Protect the linear revmap with RCU"), any irqdomain lookup requires the RCU read lock to be held. This assumes that the architecture code will be structured such as irq_enter() will be called *before* the interrupt is looked up in the irq domain. However, this isn't the case for MIPS, and a number of drivers are structured to do it the other way around when handling an interrupt in their root irqchip (secondary irqchips are OK by construction). This results in a RCU splat on a lockdep-enabled kernel when the kernel takes an interrupt from idle, as reported by Guenter Roeck. Note that this could have fired previously if any driver had used tree-based irqdomain, which always had the RCU requirement. To solve this, provide a MIPS-specific helper (do_domain_IRQ()) as the pendent of do_IRQ() that will do thing in the right order (and maybe save some cycles in the process). Ideally, MIPS would be moved over to using handle_domain_irq(), but that's much more ambitious. Reported-by: Guenter Roeck Tested-by: Guenter Roeck [maz: add dependency on CONFIG_IRQ_DOMAIN after report from the kernelci bot] Signed-off-by: Marc Zyngier Cc: Thomas Bogendoerfer Cc: Serge Semin Link: https://lore.kernel.org/r/20210705172352.GA56304@roeck-us.net Link: https://lore.kernel.org/r/20210706110647.3979002-1-maz@kernel.org --- drivers/irqchip/irq-mips-gic.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'drivers/irqchip/irq-mips-gic.c') diff --git a/drivers/irqchip/irq-mips-gic.c b/drivers/irqchip/irq-mips-gic.c index b146e069bf5b..54c7092cc61d 100644 --- a/drivers/irqchip/irq-mips-gic.c +++ b/drivers/irqchip/irq-mips-gic.c @@ -169,8 +169,8 @@ static void gic_handle_shared_int(bool chained) generic_handle_domain_irq(gic_irq_domain, GIC_SHARED_TO_HWIRQ(intr)); else - do_IRQ(irq_find_mapping(gic_irq_domain, - GIC_SHARED_TO_HWIRQ(intr))); + do_domain_IRQ(gic_irq_domain, + GIC_SHARED_TO_HWIRQ(intr)); } } @@ -320,8 +320,8 @@ static void gic_handle_local_int(bool chained) generic_handle_domain_irq(gic_irq_domain, GIC_LOCAL_TO_HWIRQ(intr)); else - do_IRQ(irq_find_mapping(gic_irq_domain, - GIC_LOCAL_TO_HWIRQ(intr))); + do_domain_IRQ(gic_irq_domain, + GIC_LOCAL_TO_HWIRQ(intr)); } } -- cgit v1.2.3