From 303fc0870f8fbfabe260c5c32b18e53458d597ea Mon Sep 17 00:00:00 2001 From: Prarit Bhargava Date: Thu, 12 Nov 2009 13:09:31 -0500 Subject: [PATCH] x86: AMD Northbridge: Verify NB's node is online Fix panic seen on some IBM and HP systems on 2.6.32-rc6: BUG: unable to handle kernel NULL pointer dereference at (null) IP: [] find_next_bit+0x77/0x9c [...] [] cpumask_next_and+0x2e/0x3b [] pci_device_probe+0x8e/0xf5 [] ? driver_sysfs_add+0x47/0x6c [] driver_probe_device+0xd9/0x1f9 [] __driver_attach+0x58/0x7c [] ? __driver_attach+0x0/0x7c [] bus_for_each_dev+0x54/0x89 [] driver_attach+0x19/0x1b [] bus_add_driver+0xd3/0x23d [] driver_register+0x98/0x109 [] __pci_register_driver+0x63/0xd3 [] ? up_read+0x26/0x2a [] ? k8temp_init+0x0/0x20 [k8temp] [] k8temp_init+0x1e/0x20 [k8temp] [] do_one_initcall+0x6d/0x185 [] sys_init_module+0xd3/0x236 [] system_call_fastpath+0x16/0x1b I put in a printk and commented out the set_dev_node() call when and got this output: quirk_amd_nb_node: current numa_node = 0x0, would set to val & 7 = 0x0 quirk_amd_nb_node: current numa_node = 0x0, would set to val & 7 = 0x1 quirk_amd_nb_node: current numa_node = 0x0, would set to val & 7 = 0x2 quirk_amd_nb_node: current numa_node = 0x0, would set to val & 7 = 0x3 I.e. the issue appears to be that the HW has set val to a valid value, however, the system is only configured for a single node -- 0, the others are offline. Check to see if the node is actually online before setting the numa node for an AMD northbridge in quirk_amd_nb_node(). Signed-off-by: Prarit Bhargava Cc: bhavna.sarathy@amd.com Cc: jbarnes@virtuousgeek.org Cc: andreas.herrmann3@amd.com LKML-Reference: <20091112180933.12532.98685.sendpatchset@prarit.bos.redhat.com> [ v2: clean up the code and add comments ] Signed-off-by: Ingo Molnar --- arch/x86/kernel/quirks.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/quirks.c b/arch/x86/kernel/quirks.c index 6c3b2c6fd772..18093d7498f0 100644 --- a/arch/x86/kernel/quirks.c +++ b/arch/x86/kernel/quirks.c @@ -499,6 +499,7 @@ static void __init quirk_amd_nb_node(struct pci_dev *dev) { struct pci_dev *nb_ht; unsigned int devfn; + u32 node; u32 val; devfn = PCI_DEVFN(PCI_SLOT(dev->devfn), 0); @@ -507,7 +508,13 @@ static void __init quirk_amd_nb_node(struct pci_dev *dev) return; pci_read_config_dword(nb_ht, 0x60, &val); - set_dev_node(&dev->dev, val & 7); + node = val & 7; + /* + * Some hardware may return an invalid node ID, + * so check it first: + */ + if (node_online(node)) + set_dev_node(&dev->dev, node); pci_dev_put(nb_ht); } -- 2.39.2