Re: [PATCH] PCI, x86: clear initial value for root info resources

On Tue, Sep 18, 2012 at 5:49 PM, Yinghai Lu [off-list ref] wrote:

On Tue, Sep 18, 2012 at 3:46 PM, Bjorn Helgaas [off-list ref] wrote:

quoted

On Fri, Sep 14, 2012 at 6:48 PM, Yinghai Lu [off-list ref] wrote:

quoted

Found one system one root bus hot remove get panic.
Panic happens when try to release hostbridge resource.

It turns out that resource get reject during put into resource tree
because of conflicts.
Also that resource parent pointer have random value.

That invalid value cause it pass through check __release_pci_root_info
and panic in release_resource.

Try to use kzalloc instead.

Don't we need the same fix for ia64 in pci_acpi_scan_root()?  Here's
what it does:

        if (windows) {
                controller->window =
                        kmalloc_node(sizeof(*controller->window) * windows,
                                     GFP_KERNEL, controller->node);

yes, but they don't support pci_set_host_bridge_release yet. so they
should not meet this problem yet.

Why should we wait to fix that bug until later?  I'm not interested in
debugging this in the future.  If you fix a bug, you should always try
to fix other occurrences of the same bug at the same time.