From: Thomas Gleixner Date: Tue, 17 Jul 2018 18:25:31 +0200 Subject: [PATCH 013/342] x86/ioapic: Don't let setaffinity unmask threaded EOI interrupt too early Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=6d53bf26f7092895193d947150b8de66ea8e226a There is an issue with threaded interrupts which are marked ONESHOT and using the fasteoi handler. if (IS_ONESHOT()) mask_irq(); .... .... cond_unmask_eoi_irq() chip->irq_eoi(); So if setaffinity is pending then the interrupt will be moved and then unmasked, which is wrong as it should be kept masked up to the point where the threaded handler finished. It's not a real problem, the interrupt will just be able to fire before the threaded handler has finished, though the irq masked state will be wrong for a bit. The patch below should cure the issue. It also renames the horribly misnomed functions so it becomes clear what they are supposed to do. Signed-off-by: Thomas Gleixner [bigeasy: add the body of the patch, use the same functions in both ifdef paths (spotted by Andy Shevchenko)] Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/kernel/apic/io_apic.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index 677508baf95a..b1a7f453415f 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -1732,7 +1732,7 @@ static bool io_apic_level_ack_pending(struct mp_chip_data *data) return false; } -static inline bool ioapic_irqd_mask(struct irq_data *data) +static inline bool ioapic_prepare_move(struct irq_data *data) { /* If we are moving the IRQ we need to mask it */ if (unlikely(irqd_is_setaffinity_pending(data))) { @@ -1743,9 +1743,9 @@ static inline bool ioapic_irqd_mask(struct irq_data *data) return false; } -static inline void ioapic_irqd_unmask(struct irq_data *data, bool masked) +static inline void ioapic_finish_move(struct irq_data *data, bool moveit) { - if (unlikely(masked)) { + if (unlikely(moveit)) { /* Only migrate the irq if the ack has been received. * * On rare occasions the broadcast level triggered ack gets @@ -1780,11 +1780,11 @@ static inline void ioapic_irqd_unmask(struct irq_data *data, bool masked) } } #else -static inline bool ioapic_irqd_mask(struct irq_data *data) +static inline bool ioapic_prepare_move(struct irq_data *data) { return false; } -static inline void ioapic_irqd_unmask(struct irq_data *data, bool masked) +static inline void ioapic_finish_move(struct irq_data *data, bool moveit) { } #endif @@ -1793,11 +1793,11 @@ static void ioapic_ack_level(struct irq_data *irq_data) { struct irq_cfg *cfg = irqd_cfg(irq_data); unsigned long v; - bool masked; + bool moveit; int i; irq_complete_move(cfg); - masked = ioapic_irqd_mask(irq_data); + moveit = ioapic_prepare_move(irq_data); /* * It appears there is an erratum which affects at least version 0x11 @@ -1852,7 +1852,7 @@ static void ioapic_ack_level(struct irq_data *irq_data) eoi_ioapic_pin(cfg->vector, irq_data->chip_data); } - ioapic_irqd_unmask(irq_data, masked); + ioapic_finish_move(irq_data, moveit); } static void ioapic_ir_ack_level(struct irq_data *irq_data)