[PATCH V5 0/4] PCI/ASPM: reconfigure ASPM following hotplug for POLICY_DEFAULT
Patel, Mayurkumar
mayurkumar.patel at intel.com
Wed Mar 29 13:16:19 PDT 2017
>On 3/29/2017 1:27 PM, Patel, Mayurkumar wrote:
>> Hi Kaya
>>
>>>
>>> On 3/28/2017 9:04 AM, Sinan Kaya wrote:
>>>> On 3/28/2017 8:52 AM, Sinan Kaya wrote:
>>>>> On 3/28/2017 2:02 AM, Patel, Mayurkumar wrote:
>>>>>> Thanks for your patches. I am seeing kernel panic after applying
>>>>>> these patches (on top of latest kernel) each time during early boot in pci_aspm_init() (any hints already?) function.
>>>>>> Need to check if it's something related to my local setup or it's because of these changes.
>>>>>> For now I don't have more details why it crashes but I will dig in further and I will provide
>>>>>> you more data as soon as I have it.
>>>>>>
>>>>>
>>>>> Interesting, I retested Qemu and I don't see an issue.
>>>>> Can you share your bootlog when you see the crash?
>>>>>
>>>> Thinking more...
>>>>
>>>> Can you add this to the top of pci_aspm_init() and try again?
>>>>
>>>> if (!pci_is_pcie(pdev))
>>>> return -EINVAL;
>>>>
>>>
>>> Did this help?
>>
>> No, It did not helped. I tested without your patches and no panic seen.
>
>I think you have a mixture of old and new patches or a mixture of old/new object files.
>pci_function_0() is no longer getting called from pci_aspm_init(). This was done in V4 of the patch.
>
>>
>> I found with your patch in pci_aspm_init() call, pdev->subordinate is not valid which causes a crash in
>> pci_function_0().
>> I tentatively started validating pdev->subordinate pointer and proceeding pci_aspm_init() without allocating link->downstream pointer,
>> then I got another following issue during boot. I will further debug it but if you have any other suggestion or some other clicks in your
>mind
>> what this could be I could try that too.
>>
>
>I think you have a mixture of old and new patches or a mixture of old/new object files.
>
>> [ 2.339374] pcie_get_aspm_reg+0x39/0x1a0
>> [ 2.387312] pcie_aspm_init_link_state+0x2aa/0x900
>> [ 2.444611] ? pci_device_add+0x20a/0x300
>
>This was also done in V4 of the patch. This was replaced by pci_aspm_init() in V5 and
>there is no call from device_add path into pci_aspm_init() function. The
>pcie_aspm_init_link_state() gets called from the pci_scan_slot() as it used to be.
>
>Can you try it on a clean tree with the following patches?
>
>https://patchwork.codeaurora.org/patch/207667/
>https://patchwork.codeaurora.org/patch/207653/
>https://patchwork.codeaurora.org/patch/207669/
>https://patchwork.codeaurora.org/patch/207651/
>
>The only change you should need on top of this is this.
>
>--- a/drivers/pci/pcie/aspm.c
>+++ b/drivers/pci/pcie/aspm.c
>@@ -847,6 +847,9 @@ int pci_aspm_init(struct pci_dev *pdev)
> if (!pdev->has_secondary_link)
> return 0;
>
>+ if (!pci_is_pcie(pdev))
>+ return -EINVAL;
>+
> link = alloc_pcie_link_state(pdev);
> if (!link)
> return -ENOMEM;
>
>
Actually, I have taken same patches of yours which proposed and applied it correctly. Will try it with clean
build if that helps.
But what I could understand from following patch is https://patchwork.codeaurora.org/patch/207653/
We still have a flow of pci_aspm_init() -> alloc_pcie_link_state() -> pci_function_0()
Where I see the first Kernel NULL pointer crash while accessing pdev->subordinate in pci_function_0() function.
To mitigate that I included following code in it.
@@ -430,8 +439,11 @@ static struct pci_dev *pci_function_0(struct pci_bus *linkbus)
{
struct pci_dev *child;
+ if (!linkbus)
+ return NULL;
+
list_for_each_entry(child, &linkbus->devices, bus_list)
if (PCI_FUNC(child->devfn) == 0)
return child;
return NULL;
Then I start seeing following error as pdev-> downstream stays NULL.
>
>> [ 0.835443] BUG: unable to handle kernel NULL pointer dereference at 000000000000003e
>> [ 0.929138] IP: pcie_capability_read_dword+0x82/0x1a0
>> [ 0.989555] PGD 0
>> [ 0.989556]
>> [ 1.031360] Oops: 0000 [#1] SMP
>> [ 1.068901] Modules linked in:
>> [ 1.105403] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 4.11.0-rc4-aspmtestv6 #24
>> [ 1.192861] Hardware name: /IC97, BIOS IV97R903 02/25/2016
>> [ 1.261600] task: ffff9141435c8000 task.stack: ffffa6b8418c0000
>> [ 1.332419] RIP: 0010:pcie_capability_read_dword+0x82/0x1a0
>> [ 1.399077] RSP: 0000:ffffa6b8418c39b0 EFLAGS: 00010246
>> [ 1.461575] RAX: 0000000000000000 RBX: 000000000000000c RCX: ffffffff85e5be08
>> [ 1.546954] RDX: ffffa6b8418c39ec RSI: 000000000000000c RDI: 0000000000000000
>> [ 1.632332] RBP: ffffa6b8418c39d8 R08: 0000000000000001 R09: 0000000000000171
>> [ 1.717707] R10: 0000000000000000 R11: 0000000000000170 R12: 0000000000000000
>> [ 1.803085] R13: ffffa6b8418c39ec R14: ffff914142e370c0 R15: 0000000000000000
>> [ 1.888462] FS: 0000000000000000(0000) GS:ffff914155c80000(0000) knlGS:0000000000000000
>> [ 1.985278] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> [ 2.054017] CR2: 000000000000003e CR3: 0000000300e09000 CR4: 00000000003406e0
>> [ 2.139396] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>> [ 2.224772] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>> [ 2.310150] Call Trace:
>> [ 2.339374] pcie_get_aspm_reg+0x39/0x1a0
>> [ 2.387312] pcie_aspm_init_link_state+0x2aa/0x900
>> [ 2.444611] ? pci_device_add+0x20a/0x300
>> [ 2.492554] pci_scan_slot+0xd7/0x110
>> [ 2.536335] pci_scan_child_bus+0x30/0x180
>> [ 2.585313] pci_scan_bridge+0x3f0/0x670
>> [ 2.632215] ? pci_scan_single_device+0x6d/0xd0
>> [ 2.686394] pci_scan_child_bus+0x9f/0x180
>> [ 2.735375] acpi_pci_root_create+0x182/0x1de
>> [ 2.787475] pci_acpi_scan_root+0x15f/0x1b0
>> [ 2.837493] acpi_pci_root_add+0x3bf/0x4c4
>> [ 2.886474] acpi_bus_attach+0xdf/0x18e
>> [ 2.932336] acpi_bus_attach+0x135/0x18e
>> [ 2.979234] acpi_bus_attach+0x135/0x18e
>> [ 3.026135] acpi_bus_scan+0x6e/0x8d
>> [ 3.068877] ? acpi_sleep_proc_init+0x28/0x28
>> [ 3.120976] acpi_scan_init+0xda/0x237
>> [ 3.165795] ? acpi_sleep_proc_init+0x28/0x28
>> [ 3.217895] acpi_init+0x2be/0x347
>>
>>>
>>> --
>>> Sinan Kaya
>>> Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
>>> Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
>> Intel Deutschland GmbH
>> Registered Address: Am Campeon 10-12, 85579 Neubiberg, Germany
>> Tel: +49 89 99 8853-0, www.intel.de
>> Managing Directors: Christin Eisenschmid, Christian Lamprechter
>> Chairperson of the Supervisory Board: Nicole Lau
>> Registered Office: Munich
>> Commercial Register: Amtsgericht Muenchen HRB 186928
>>
>>
>
>
>--
>Sinan Kaya
>Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
>Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
Intel Deutschland GmbH
Registered Address: Am Campeon 10-12, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de
Managing Directors: Christin Eisenschmid, Christian Lamprechter
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928
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