• Kenji Kaneshige's avatar
    pciehp: fix NULL dereference in interrupt handler · dbd79aed
    Kenji Kaneshige authored
    Fix the following NULL dereference problem reported from Pierre Ossman
    and Ingo Molnar.
    
    pciehp: HPC vendor_id 8086 device_id 27d0 ss_vid 0 ss_did 0
    pciehp: pciehp_find_slot: slot (device=0x0) not found
    BUG: unable to handle kernel NULL pointer dereference at 0000000000000070
    IP: [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113
    PGD 0
    Oops: 0000 [1]
    CPU 0
    Modules linked in:
    Pid: 1, comm: swapper Tainted: G        W 2.6.26-rc3-sched-devel.git-00001-g2b99b26-dirty #170
    RIP: 0010:[<ffffffff80494a8b>]  [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113
    RSP: 0000:ffff81003f83fbb0  EFLAGS: 00010046
    RAX: 0000000000000039 RBX: 0000000000000000 RCX: 0000000000000000
    RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000046
    RBP: ffff81003f83fbd0 R08: 0000000000000001 R09: ffffffff80245103
    R10: 0000000000000020 R11: 0000000000000000 R12: ffff81003ea53a30
    R13: 0000000000000000 R14: 0000000000000011 R15: ffffffff80495926
    FS:  0000000000000000(0000) GS:ffffffff80be7400(0000) knlGS:0000000000000000
    CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
    CR2: 0000000000000070 CR3: 0000000000201000 CR4: 00000000000006a0
    DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
    DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
    Process swapper (pid: 1, threadinfo ffff81003f83e000, task ffff81003f840000)
    Stack:  0000000000000008 ffff81003f83fbf6 ffff81003ea53a30 0000000000000008
     ffff81003f83fc10 ffffffff80495ab4 0000000000000011 0000000000000002
     0000000000000202 0000000000000202 00000000fffffff4 ffff81003ea53a30
    Call Trace:
     [<ffffffff80495ab4>] pcie_isr+0x18e/0x1bc
     [<ffffffff80260831>] request_irq+0x106/0x12f
     [<ffffffff80495fb6>] pcie_init+0x15e/0x6cc
     [<ffffffff804933a3>] pciehp_probe+0x64/0x541
     [<ffffffff8048f4e7>] pcie_port_probe_service+0x4c/0x76
     [<ffffffff8054af70>] driver_probe_device+0xd4/0x1f0
     [<ffffffff8054b108>] __driver_attach+0x7c/0x7e
     [<ffffffff8054b08c>] ? __driver_attach+0x0/0x7e
     [<ffffffff8054a4b6>] bus_for_each_dev+0x53/0x7d
     [<ffffffff8054ad3c>] driver_attach+0x1c/0x1e
     [<ffffffff8054a9c2>] bus_add_driver+0xdd/0x25b
     [<ffffffff80c09d3d>] ? pcied_init+0x0/0x8b
     [<ffffffff8054b288>] driver_register+0x5f/0x13e
     [<ffffffff80c09d3d>] ? pcied_init+0x0/0x8b
     [<ffffffff8048f441>] pcie_port_service_register+0x47/0x49
     [<ffffffff80c09d52>] pcied_init+0x15/0x8b
     [<ffffffff80bf3938>] kernel_init+0x75/0x243
     [<ffffffff808639d2>] ? _spin_unlock_irq+0x2b/0x3a
     [<ffffffff80228d1f>] ? finish_task_switch+0x57/0x9a
     [<ffffffff8020c258>] child_rip+0xa/0x12
     [<ffffffff8020bcec>] ? restore_args+0x0/0x30
     [<ffffffff80bf38c3>] ? kernel_init+0x0/0x243
     [<ffffffff8020c24e>] ? child_rip+0x0/0x12
    
    Code: 83 80 00 00 00 48 39 f0 75 e1 0f b6 c9 48 c7 c2 00 0e 8d 80 48 c7 c6 8a 60 a6 80 48 c7 c7 10 db a8 80 31 c0 e8 3f 8d d9 ff 31 db <48> 8b 43 70 48 8d 75 ef 48 89 df ff 50 30 80 7d ef 00 74 37 48
    RIP  [<ffffffff80494a8b>] pciehp_handle_presence_change+0x7e/0x113
     RSP <ffff81003f83fbb0>
    CR2: 0000000000000070
    Kernel panic - not syncing: Fatal exception
    
    The situation under which it occurs is hw and timing related: it appears
    to happen on a system that has PCI hotplug hardware but with no active
    hotplug cards, and another interrupt in the same (shared) IRQ line
    arrives too early, before the hotplug-slot entry has been set up - as
    triggered by CONFIG_DEBUG_SHIRQ=y:
    
    This patch contains the following two fixes.
    
    (1) Clear all events bits in Slot Status register to prevent the pciehp
        driver from detecting the spurious events that would have been occur
        before pciehp loading.
    
    (2) Add check whether slot initialization had been already done.
    
    This is short term fix. We need more structural fixes to install
    interrupt handler after slot initialization is done.
    Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    Signed-off-by: default avatarKenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
    Signed-off-by: default avatarKristen Carlson Accardi <kristen.c.accardi@intel.com>
    Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
    dbd79aed
pciehp.h 7.04 KB