• Prarit Bhargava's avatar
    x86: AMD Northbridge: Verify NB's node is online · 303fc087
    Prarit Bhargava authored
    
    
    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: [<ffffffff8120bf3f>] find_next_bit+0x77/0x9c
      [...]
      [<ffffffff8120bbde>] cpumask_next_and+0x2e/0x3b
      [<ffffffff81225c62>] pci_device_probe+0x8e/0xf5
      [<ffffffff812b9be6>] ? driver_sysfs_add+0x47/0x6c
      [<ffffffff812b9da5>] driver_probe_device+0xd9/0x1f9
      [<ffffffff812b9f1d>] __driver_attach+0x58/0x7c
      [<ffffffff812b9ec5>] ? __driver_attach+0x0/0x7c
      [<ffffffff812b9298>] bus_for_each_dev+0x54/0x89
      [<ffffffff812b9b4f>] driver_attach+0x19/0x1b
      [<ffffffff812b97ae>] bus_add_driver+0xd3/0x23d
      [<ffffffff812ba1e7>] driver_register+0x98/0x109
      [<ffffffff81225ed0>] __pci_register_driver+0x63/0xd3
      [<ffffffff81072776>] ? up_read+0x26/0x2a
      [<ffffffffa0081000>] ? k8temp_init+0x0/0x20 [k8temp]
      [<ffffffffa008101e>] k8temp_init+0x1e/0x20 [k8temp]
      [<ffffffff8100a073>] do_one_initcall+0x6d/0x185
      [<ffffffff8108d765>] sys_init_module+0xd3/0x236
      [<ffffffff81011ac2>] 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: default avatarPrarit Bhargava <prarit@redhat.com>
    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: default avatarIngo Molnar <mingo@elte.hu>
    303fc087