3.16.82-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> commit df4393424af3fbdcd5c404077176082a8ce459c4 upstream. 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(); if (setaffinity_pending) { mask_ioapic(); ... move_affinity(); unmask_ioapic(); } So if setaffinity is pending the interrupt will be moved and then unconditionally unmasked at the ioapic level, which is wrong in two aspects: 1) It should be kept masked up to the point where the threaded handler finished. 2) The physical chip state and the software masked state are inconsistent Guard both the mask and the unmask with a check for the software masked state. If the line is marked masked then the ioapic line is also masked, so both mask_ioapic() and unmask_ioapic() can be skipped safely. Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Andy Shevchenko <andy.shevchenko@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Sebastian Siewior <bigeasy@xxxxxxxxxxxxx> Fixes: 3aa551c9b4c4 ("genirq: add threaded interrupt handler support") Link: https://lkml.kernel.org/r/20191017101938.321393687@xxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> [bwh: Backported to 3.16: Keep using {,un}mask_iopaic_irq()] Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- arch/x86/kernel/apic/io_apic.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -2377,9 +2377,10 @@ static bool io_apic_level_ack_pending(st static inline bool ioapic_irqd_mask(struct irq_data *data, struct irq_cfg *cfg) { - /* If we are moving the irq we need to mask it */ + /* If we are moving the IRQ we need to mask it */ if (unlikely(irqd_is_setaffinity_pending(data))) { - mask_ioapic(cfg); + if (!irqd_irq_masked(data)) + mask_ioapic(cfg); return true; } return false; @@ -2417,7 +2418,9 @@ static inline void ioapic_irqd_unmask(st */ if (!io_apic_level_ack_pending(cfg)) irq_move_masked_irq(data); - unmask_ioapic(cfg); + /* If the IRQ is masked in the core, leave it: */ + if (!irqd_irq_masked(data)) + unmask_ioapic(cfg); } } #else