From bd0e501e1a4813fa36a4cf9842aaf430323a03c3 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Tue, 5 Nov 2024 17:18:13 +0000 Subject: [PATCH] hw/i386/pc: Don't try to init PCI NICs if there is no PCI bus The 'isapc' machine type has no PCI bus, but pc_nic_init() still calls pci_init_nic_devices() passing it a NULL bus pointer. This causes the clang sanitizer to complain: $ ./build/clang/qemu-system-i386 -M isapc ../../hw/pci/pci.c:1866:39: runtime error: member access within null pointer of type 'PCIBus' (aka 'struct PCIBus') SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../../hw/pci/pci.c:1866:39 in This is because pci_init_nic_devices() does &bus->qbus which is undefined behaviour on a NULL pointer even though we're not actually dereferencing the pointer. (We don't actually crash as a result, so if you aren't running a sanitizer build then there are no user-visible effects.) Make pc_nic_init() avoid trying to initialize PCI NICs on a non-PCI system. Cc: qemu-stable@nongnu.org Fixes: 8d39f9ba14d64 ("hw/i386/pc: use qemu_get_nic_info() and pci_init_nic_devices()") Signed-off-by: Peter Maydell Link: https://lore.kernel.org/r/20241105171813.3031969-1-peter.maydell@linaro.org Signed-off-by: Paolo Bonzini --- hw/i386/pc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/hw/i386/pc.c b/hw/i386/pc.c index 830614d930..f9147fecbd 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -1252,7 +1252,9 @@ void pc_nic_init(PCMachineClass *pcmc, ISABus *isa_bus, PCIBus *pci_bus) } /* Anything remaining should be a PCI NIC */ - pci_init_nic_devices(pci_bus, mc->default_nic); + if (pci_bus) { + pci_init_nic_devices(pci_bus, mc->default_nic); + } rom_reset_order_override(); }