diff options
| author | Marc Zyngier <maz@kernel.org> | 2021-07-06 11:38:59 +0100 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2021-07-09 10:18:58 +0100 |
| commit | 1fee9db9b42d821e8007289d4eea74bdf85b1543 (patch) | |
| tree | 6f5b28725cd0b60ac05ccc13b073328b13eec4a2 /drivers/irqchip/irq-mips-gic.c | |
| parent | 0e3c1f30b03599f2ee8ff3327eca53c99564ba13 (diff) | |
| download | linux-1fee9db9b42d821e8007289d4eea74bdf85b1543.tar.bz2 | |
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 <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
[maz: add dependency on CONFIG_IRQ_DOMAIN after report from the kernelci bot]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Serge Semin <fancer.lancer@gmail.com>
Link: https://lore.kernel.org/r/20210705172352.GA56304@roeck-us.net
Link: https://lore.kernel.org/r/20210706110647.3979002-1-maz@kernel.org
Diffstat (limited to 'drivers/irqchip/irq-mips-gic.c')
| -rw-r--r-- | drivers/irqchip/irq-mips-gic.c | 8 |
1 files changed, 4 insertions, 4 deletions
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)); } } |