Messages in this thread Patch in this message | | | Date | Mon, 28 Feb 2022 17:40:39 -0000 | From | "irqchip-bot for Marc Zyngier" <> | Subject | [irqchip: irq/irqchip-next] irqchip/qcom-pdc: Fix broken locking |
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The following commit has been merged into the irq/irqchip-next branch of irqchip:
Commit-ID: bd9fce2e5ea12ee82821dbc725fa4f97f9094ba1 Gitweb: https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms/bd9fce2e5ea12ee82821dbc725fa4f97f9094ba1 Author: Marc Zyngier <maz@kernel.org> AuthorDate: Thu, 24 Feb 2022 10:12:25 Committer: Marc Zyngier <maz@kernel.org> CommitterDate: Mon, 28 Feb 2022 17:32:26
irqchip/qcom-pdc: Fix broken locking
pdc_enable_intr() serves as a primitive to qcom_pdc_gic_{en,dis}able, and has a raw spinlock for mutual exclusion, which is uses with interruptible primitives.
This means that this critical section can itself be interrupted. Should the interrupt also be a PDC interrupt, and the endpoint driver perform an irq_disable() on that interrupt, we end-up in a deadlock.
Fix this by using the irqsave/irqrestore variants of the locking primitives.
Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220224101226.88373-5-maz@kernel.org --- drivers/irqchip/qcom-pdc.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/irqchip/qcom-pdc.c b/drivers/irqchip/qcom-pdc.c index 837ca69..0cd20dd 100644 --- a/drivers/irqchip/qcom-pdc.c +++ b/drivers/irqchip/qcom-pdc.c @@ -55,17 +55,18 @@ static u32 pdc_reg_read(int reg, u32 i) static void pdc_enable_intr(struct irq_data *d, bool on) { int pin_out = d->hwirq; + unsigned long flags; u32 index, mask; u32 enable; index = pin_out / 32; mask = pin_out % 32; - raw_spin_lock(&pdc_lock); + raw_spin_lock_irqsave(&pdc_lock, flags); enable = pdc_reg_read(IRQ_ENABLE_BANK, index); enable = on ? ENABLE_INTR(enable, mask) : CLEAR_INTR(enable, mask); pdc_reg_write(IRQ_ENABLE_BANK, index, enable); - raw_spin_unlock(&pdc_lock); + raw_spin_unlock_irqrestore(&pdc_lock, flags); } static void qcom_pdc_gic_disable(struct irq_data *d)
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