Hello, While fuzzing, I found an input that triggers an assertion failure in pci_bus_get_irq_level through ich9_lpc_update_apic:
int pci_bus_get_irq_level(PCIBus *, int): Assertion `irq_num < bus->nirq' failed. #8 0x7fc7d4fa4091 in __assert_fail /build/glibc-GwnBeO/glibc-2.30/assert/assert.c:101:3 #9 0x5557c8639fe1 in pci_bus_get_irq_level hw/pci/pci.c:268:5 #10 0x5557c6b05693 in ich9_lpc_update_apic hw/isa/lpc_ich9.c:250:14 #11 0x5557c6b09167 in ich9_set_sci hw/isa/lpc_ich9.c:355:9 #12 0x5557c7c96f42 in qemu_set_irq hw/core/irq.c:44:5 #13 0x5557c7959379 in acpi_update_sci hw/acpi/core.c:723:5 #14 0x5557c7977dc3 in ich9_pm_update_sci_fn hw/acpi/ich9.c:56:5 #15 0x5557c795a80f in acpi_pm_evt_write hw/acpi/core.c:456:9 #16 0x5557c671a17b in memory_region_write_accessor memory.c:496:5 I can reproduce it in a qemu 5.0 build using: cat << EOF | qemu-system-i386 -M pc-q35-5.0 -display none -nodefaults -nographic -qtest stdio outl 0xcf8 0x8400f841 outl 0xcfc 0xebed205d outl 0x5d02 0xedf82049 EOF I also uploaded the above trace, in case the formatting is broken: curl https://paste.debian.net/plain/1146096 | qemu-system-i386 -M pc-q35-5.0 -display none -nodefaults -nographic -qtest stdio Please let me know if I can provide any further info. -Alex