On Tue, Oct 1, 2024 at 11:11 PM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote:
>
> On Thu, Sep 26, 2024 at 03:09:23PM +0200, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
> >
> > Since adding the PCI power control code, we may end up with a race
> > between the pwrctl platform device rescanning the bus and the host
> > controller probe function. The latter needs to take the rescan lock when
> > adding devices or may crash.
> >
> > Reported-by: Konrad Dybcio <konradybcio@xxxxxxxxxx>
> > Fixes: 4565d2652a37 ("PCI/pwrctl: Add PCI power control core code")
> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
> > ---
> > drivers/pci/probe.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> > index 4f68414c3086..f1615805f5b0 100644
> > --- a/drivers/pci/probe.c
> > +++ b/drivers/pci/probe.c
> > @@ -3105,7 +3105,9 @@ int pci_host_probe(struct pci_host_bridge *bridge)
> > list_for_each_entry(child, &bus->children, node)
> > pcie_bus_configure_settings(child);
> >
> > + pci_lock_rescan_remove();
> > pci_bus_add_devices(bus);
> > + pci_unlock_rescan_remove();
>
> Seems like we do need locking here, but don't we need a more
> comprehensive change? There are many other callers of
> pci_bus_add_devices(), and most of them look similarly unprotected.
>
