From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Marc Zyngier <maz@kernel.org>,
x86@kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
linux-pci@vger.kernel.org, Keith Busch <kbusch@kernel.org>,
Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>
Subject: [patch 5/7] genirq: Sanitize state handling in check_irq_resend()
Date: Fri, 06 Mar 2020 14:03:46 +0100 [thread overview]
Message-ID: <20200306130623.882129117@linutronix.de> (raw)
In-Reply-To: 20200306130341.199467200@linutronix.de
The code sets IRQS_REPLAY unconditionally whether the resend happens or
not. That doesn't have bad side effects right now, but inconsistent state
is always a latent source of problems.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/irq/resend.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)
--- a/kernel/irq/resend.c
+++ b/kernel/irq/resend.c
@@ -93,6 +93,8 @@ static int irq_sw_resend(struct irq_desc
*/
int check_irq_resend(struct irq_desc *desc)
{
+ int err = 0;
+
/*
* We do not resend level type interrupts. Level type interrupts
* are resent by hardware when they are still active. Clear the
@@ -106,13 +108,17 @@ int check_irq_resend(struct irq_desc *de
if (desc->istate & IRQS_REPLAY)
return -EBUSY;
- if (desc->istate & IRQS_PENDING) {
- desc->istate &= ~IRQS_PENDING;
- desc->istate |= IRQS_REPLAY;
+ if (!(desc->istate & IRQS_PENDING))
+ return 0;
- if (!desc->irq_data.chip->irq_retrigger ||
- !desc->irq_data.chip->irq_retrigger(&desc->irq_data))
- return irq_sw_resend(desc);
- }
- return 0;
+ desc->istate &= ~IRQS_PENDING;
+
+ if (!desc->irq_data.chip->irq_retrigger ||
+ !desc->irq_data.chip->irq_retrigger(&desc->irq_data))
+ err = irq_sw_resend(desc);
+
+ /* If the retrigger was successfull, mark it with the REPLAY bit */
+ if (!err)
+ desc->istate |= IRQS_REPLAY;
+ return err;
}
next prev parent reply other threads:[~2020-03-06 13:09 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-06 13:03 [patch 0/7] genirq/PCI: Sanitize interrupt injection Thomas Gleixner
2020-03-06 13:03 ` [patch 1/7] genirq/debugfs: Add missing sanity checks to " Thomas Gleixner
2020-03-06 13:15 ` Marc Zyngier
2020-03-06 13:03 ` [patch 2/7] genirq: Add protection against unsafe usage of generic_handle_irq() Thomas Gleixner
2020-03-06 13:36 ` Marc Zyngier
2020-03-06 13:03 ` [patch 3/7] x86/apic/vector: Force interupt handler invocation to irq context Thomas Gleixner
2020-03-06 13:03 ` [patch 4/7] genirq: Add return value to check_irq_resend() Thomas Gleixner
2020-03-06 13:44 ` Marc Zyngier
2020-03-06 13:03 ` Thomas Gleixner [this message]
2020-03-06 13:46 ` [patch 5/7] genirq: Sanitize state handling in check_irq_resend() Marc Zyngier
2020-03-06 13:03 ` [patch 6/7] genirq: Provide interrupt injection mechanism Thomas Gleixner
2020-03-06 13:52 ` Marc Zyngier
2020-03-06 18:34 ` Kuppuswamy Sathyanarayanan
2020-03-06 13:03 ` [patch 7/7] PCI/AER: Fix the broken interrupt injection Thomas Gleixner
2020-03-06 18:32 ` Kuppuswamy Sathyanarayanan
2020-03-06 19:29 ` Kuppuswamy Sathyanarayanan
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