2017-10-26 08:38:41

by Sander Eikelenboom

[permalink] [raw]
Subject: Re: ce56a86e2a ("x86/mm: Limit mmap() of /dev/mem to valid physical addresses"): kernel BUG at arch/x86/mm/physaddr.c:79!

On 26/10/17 00:02, Craig Bergstrom wrote:
> Thanks for the notification, my apologies for the breakage. I'll take a
> close look and see if I can figure out what went wrong.
>
> Sander, any chance you can send /proc/iomem and the inputs to the mmap call
> that fail on your affected system?

Hi Craig,

The output from /proc/iomem is simple to get and attached.
The mmap call is probably issued by qemu and will require more digging.

I don't know if there is that much time left for 4.14, since we are at
RC6 already.

--
Sander


>
>
> On Wed, Oct 25, 2017 at 2:50 PM, Boris Ostrovsky <[email protected]
>> wrote:
>
>> On 10/23/2017 10:44 PM, Fengguang Wu wrote:
>>> Greetings,
>>>
>>> 0day kernel testing robot got the below dmesg and the first bad commit is
>>>
>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>> master
>>>
>>> commit ce56a86e2ade45d052b3228cdfebe913a1ae7381
>>> Author: Craig Bergstrom <[email protected]>
>>> AuthorDate: Thu Oct 19 13:28:56 2017 -0600
>>> Commit: Ingo Molnar <[email protected]>
>>> CommitDate: Fri Oct 20 09:48:00 2017 +0200
>>>
>>> x86/mm: Limit mmap() of /dev/mem to valid physical addresses
>>
>> Also note
>> https://lists.xenproject.org/archives/html/xen-devel/2017-10/msg02935.html
>>
>> -boris
>>
>


Attachments:
proc-iomem (3.68 kB)

2017-10-26 08:13:24

by Sander Eikelenboom

[permalink] [raw]
Subject: Re: ce56a86e2a ("x86/mm: Limit mmap() of /dev/mem to valid physical addresses"): kernel BUG at arch/x86/mm/physaddr.c:79!

On 26/10/17 10:05, Sander Eikelenboom wrote:
> On 26/10/17 00:02, Craig Bergstrom wrote:
>> Thanks for the notification, my apologies for the breakage. I'll take a
>> close look and see if I can figure out what went wrong.
>>
>> Sander, any chance you can send /proc/iomem and the inputs to the mmap call
>> that fail on your affected system?
>
> Hi Craig,
>
> The output from /proc/iomem is simple to get and attached.
> The mmap call is probably issued by qemu and will require more digging.

Ahh grepping qemu gave a pointer, it's probably the code in:

http://xenbits.xen.org/gitweb/?p=qemu-xen.git;a=blob;f=hw/xen/xen_pt_msi.c;h=ff9a79f5d27ad7d74a1b22297be560feb455063c;hb=5cd7ce5dde3f228b3b669ed9ca432f588947bd40

around line 571, that would also explain why it's only this device that
has the problem, since it's the only one trying to use MSI(-X)
interrupts. Will see it i can add some logging to that function.

--
Sander


>
> I don't know if there is that much time left for 4.14, since we are at
> RC6 already.
>
> --
> Sander
>
>
>>
>>
>> On Wed, Oct 25, 2017 at 2:50 PM, Boris Ostrovsky <[email protected]
>>> wrote:
>>
>>> On 10/23/2017 10:44 PM, Fengguang Wu wrote:
>>>> Greetings,
>>>>
>>>> 0day kernel testing robot got the below dmesg and the first bad commit is
>>>>
>>>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
>>> master
>>>>
>>>> commit ce56a86e2ade45d052b3228cdfebe913a1ae7381
>>>> Author: Craig Bergstrom <[email protected]>
>>>> AuthorDate: Thu Oct 19 13:28:56 2017 -0600
>>>> Commit: Ingo Molnar <[email protected]>
>>>> CommitDate: Fri Oct 20 09:48:00 2017 +0200
>>>>
>>>> x86/mm: Limit mmap() of /dev/mem to valid physical addresses
>>>
>>> Also note
>>> https://lists.xenproject.org/archives/html/xen-devel/2017-10/msg02935.html
>>>
>>> -boris
>>>
>>
>


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