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hw/i386/pc: Don't try to init PCI NICs if there is no PCI bus

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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 <peter.maydell@linaro.org>
Link: https://lore.kernel.org/r/20241105171813.3031969-1-peter.maydell@linaro.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Peter Maydell 2024-11-05 17:18:13 +00:00 committed by Paolo Bonzini
parent 88dd060db9
commit bd0e501e1a
1 changed files with 3 additions and 1 deletions
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4
hw/i386/pc.c
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@ -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();
}