Re: [PATCH] powerpc/pseries: extract host bridge from pci_bus prior to bus removal
From: Daniel Axtens <hidden>
Date: 2021-04-16 07:15:09
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Hi Tyrel,
The pci_bus->bridge reference may no longer be valid after pci_bus_remove() resulting in passing a bad value to device_unregister() for the associated bridge device. Store the host_bridge reference in a separate variable prior to pci_bus_remove().
The patch certainly seems to do what you say. I'm not really up on the innards of PCI, so I'm struggling to figure out by what code path pci_bus_remove() might invalidate pci_bus->bridge? A quick look at pci_remove_bus was not very illuminating but I didn't chase down every call it made. Kind regards, Daniel
quoted hunk ↗ jump to hunk
Fixes: 7340056567e3 ("powerpc/pci: Reorder pci bus/bridge unregistration during PHB removal") Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com> --- arch/powerpc/platforms/pseries/pci_dlpar.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)diff --git a/arch/powerpc/platforms/pseries/pci_dlpar.c b/arch/powerpc/platforms/pseries/pci_dlpar.c index f9ae17e8a0f4..a8f9140a24fa 100644 --- a/arch/powerpc/platforms/pseries/pci_dlpar.c +++ b/arch/powerpc/platforms/pseries/pci_dlpar.c@@ -50,6 +50,7 @@ EXPORT_SYMBOL_GPL(init_phb_dynamic); int remove_phb_dynamic(struct pci_controller *phb) { struct pci_bus *b = phb->bus; + struct pci_host_bridge *host_bridge = to_pci_host_bridge(b->bridge); struct resource *res; int rc, i;@@ -76,7 +77,8 @@ int remove_phb_dynamic(struct pci_controller *phb) /* Remove the PCI bus and unregister the bridge device from sysfs */ phb->bus = NULL; pci_remove_bus(b); - device_unregister(b->bridge); + host_bridge->bus = NULL; + device_unregister(&host_bridge->dev); /* Now release the IO resource */ if (res->flags & IORESOURCE_IO)-- 2.27.0