Am 5. November 2024 17:18:13 UTC schrieb Peter Maydell
<peter.mayd...@linaro.org>:
>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-sta...@nongnu.org
>Fixes: 8d39f9ba14d64 ("hw/i386/pc: use qemu_get_nic_info() and
>pci_init_nic_devices()")
>Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
>---
>This shows up if you run "make check" on a ubsan build.
>---
> 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 2047633e4cf..1af1a1a1823 100644
>--- a/hw/i386/pc.c
>+++ b/hw/i386/pc.c
>@@ -1251,7 +1251,9 @@ 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);
>+ }
Reviewed-by: Bernhard Beschow <shen...@gmail.com>
>
> rom_reset_order_override();
> }
