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5fa5595072
Baoquan reported that after triggering a crash the subsequent crash-kernel
fails to boot about half of the time. It triggers a NULL pointer
dereference in the periodic tick code.
This happens because the legacy timer interrupt (IRQ0) is resent in
software which happens in soft interrupt (tasklet) context. In this context
get_irq_regs() returns NULL which leads to the NULL pointer dereference.
The reason for the resend is a spurious APIC interrupt on the IRQ0 vector
which is captured and leads to a resend when the legacy timer interrupt is
enabled. This is wrong because the legacy PIC interrupts are level
triggered and therefore should never be resent in software, but nothing
ever sets the IRQ_LEVEL flag on those interrupts, so the core code does not
know about their trigger type.
Ensure that IRQ_LEVEL is set when the legacy PCI interrupts are set up.
Fixes: a4633adcdb ("[PATCH] genirq: add genirq sw IRQ-retrigger")
Reported-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Baoquan He <bhe@redhat.com>
Link: https://lore.kernel.org/r/87mt6rjrra.ffs@tglx
108 lines
2.9 KiB
C
108 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/linkage.h>
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#include <linux/errno.h>
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#include <linux/signal.h>
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#include <linux/sched.h>
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#include <linux/ioport.h>
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#include <linux/interrupt.h>
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#include <linux/irq.h>
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#include <linux/timex.h>
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#include <linux/random.h>
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#include <linux/kprobes.h>
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#include <linux/init.h>
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#include <linux/kernel_stat.h>
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#include <linux/device.h>
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#include <linux/bitops.h>
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#include <linux/acpi.h>
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#include <linux/io.h>
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#include <linux/delay.h>
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#include <linux/pgtable.h>
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#include <linux/atomic.h>
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#include <asm/timer.h>
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#include <asm/hw_irq.h>
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#include <asm/desc.h>
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#include <asm/io_apic.h>
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#include <asm/acpi.h>
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#include <asm/apic.h>
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#include <asm/setup.h>
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#include <asm/i8259.h>
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#include <asm/traps.h>
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#include <asm/prom.h>
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/*
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* ISA PIC or low IO-APIC triggered (INTA-cycle or APIC) interrupts:
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* (these are usually mapped to vectors 0x30-0x3f)
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*/
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/*
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* The IO-APIC gives us many more interrupt sources. Most of these
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* are unused but an SMP system is supposed to have enough memory ...
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* sometimes (mostly wrt. hw bugs) we get corrupted vectors all
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* across the spectrum, so we really want to be prepared to get all
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* of these. Plus, more powerful systems might have more than 64
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* IO-APIC registers.
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*
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* (these are usually mapped into the 0x30-0xff vector range)
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*/
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DEFINE_PER_CPU(vector_irq_t, vector_irq) = {
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[0 ... NR_VECTORS - 1] = VECTOR_UNUSED,
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};
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void __init init_ISA_irqs(void)
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{
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struct irq_chip *chip = legacy_pic->chip;
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int i;
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/*
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* Try to set up the through-local-APIC virtual wire mode earlier.
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*
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* On some 32-bit UP machines, whose APIC has been disabled by BIOS
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* and then got re-enabled by "lapic", it hangs at boot time without this.
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*/
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init_bsp_APIC();
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legacy_pic->init(0);
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for (i = 0; i < nr_legacy_irqs(); i++) {
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irq_set_chip_and_handler(i, chip, handle_level_irq);
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irq_set_status_flags(i, IRQ_LEVEL);
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}
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}
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void __init init_IRQ(void)
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{
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int i;
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/*
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* On cpu 0, Assign ISA_IRQ_VECTOR(irq) to IRQ 0..15.
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* If these IRQ's are handled by legacy interrupt-controllers like PIC,
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* then this configuration will likely be static after the boot. If
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* these IRQs are handled by more modern controllers like IO-APIC,
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* then this vector space can be freed and re-used dynamically as the
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* irq's migrate etc.
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*/
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for (i = 0; i < nr_legacy_irqs(); i++)
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per_cpu(vector_irq, 0)[ISA_IRQ_VECTOR(i)] = irq_to_desc(i);
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BUG_ON(irq_init_percpu_irqstack(smp_processor_id()));
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x86_init.irqs.intr_init();
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}
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void __init native_init_IRQ(void)
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{
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/* Execute any quirks before the call gates are initialised: */
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x86_init.irqs.pre_vector_init();
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idt_setup_apic_and_irq_gates();
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lapic_assign_system_vectors();
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if (!acpi_ioapic && !of_ioapic && nr_legacy_irqs()) {
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/* IRQ2 is cascade interrupt to second interrupt controller */
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if (request_irq(2, no_action, IRQF_NO_THREAD, "cascade", NULL))
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pr_err("%s: request_irq() failed\n", "cascade");
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}
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}
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