* Re: [uml-devel] UML regression with latest RC 4.11-rc2
2017-03-17 17:04 ` Anton Ivanov
@ 2017-03-17 17:10 ` Richard Weinberger
2017-03-17 17:25 ` Anton Ivanov
2017-03-17 17:33 ` Richard Weinberger
2 siblings, 0 replies; 8+ messages in thread
From: Richard Weinberger @ 2017-03-17 17:10 UTC (permalink / raw)
To: Anton Ivanov; +Cc: user-mode-linux-devel@lists.sourceforge.net
Anton,
Am 17.03.2017 um 18:04 schrieb Anton Ivanov:
> On 17/03/17 16:56, Richard Weinberger wrote:
>> Anton,
>>
>> On Fri, Mar 17, 2017 at 8:51 AM, Anton Ivanov
>> <anton.ivanov@kot-begemot.co.uk> wrote:
>>> Hi list, hi Richard
>>>
>>> There is an extra check in mm/mmap.c which now throws a WARN on every
>>> page in making UML unusable with the latest 4.11-rc2
>> Which WARN? Can you find the offending commit?
>
> mm/mmap.c line 1112
>
> I spent the day polishing the epoll patch so have not had the time to look at this.
>
> It works fine with the 3 warns there commented out.
Hm, it does not trigger here. Can you share your .config?
Thanks,
//richard
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [uml-devel] UML regression with latest RC 4.11-rc2
2017-03-17 17:04 ` Anton Ivanov
2017-03-17 17:10 ` Richard Weinberger
@ 2017-03-17 17:25 ` Anton Ivanov
2017-03-17 17:33 ` Richard Weinberger
2 siblings, 0 replies; 8+ messages in thread
From: Anton Ivanov @ 2017-03-17 17:25 UTC (permalink / raw)
To: user-mode-linux-devel
On 17/03/17 17:04, Anton Ivanov wrote:
> On 17/03/17 16:56, Richard Weinberger wrote:
>> Anton,
>>
>> On Fri, Mar 17, 2017 at 8:51 AM, Anton Ivanov
>> <anton.ivanov@kot-begemot.co.uk> wrote:
>>> Hi list, hi Richard
>>>
>>> There is an extra check in mm/mmap.c which now throws a WARN on every
>>> page in making UML unusable with the latest 4.11-rc2
>> Which WARN? Can you find the offending commit?
> mm/mmap.c line 1112
>
> I spent the day polishing the epoll patch so have not had the time to
> look at this.
>
> It works fine with the 3 warns there commented out.
It looks like the culprit is an SMP mmap race fix
e86f15ee64d8ee46255d964d55f74f5ba9af8c36
A.
>
> A.
>
>
> ------------------------------------------------------------------------------
> Check out the vibrant tech community on one of the world's most
> engaging tech sites, Slashdot.org! http://sdm.link/slashdot
> _______________________________________________
> User-mode-linux-devel mailing list
> User-mode-linux-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
>
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [uml-devel] UML regression with latest RC 4.11-rc2
2017-03-17 17:04 ` Anton Ivanov
2017-03-17 17:10 ` Richard Weinberger
2017-03-17 17:25 ` Anton Ivanov
@ 2017-03-17 17:33 ` Richard Weinberger
2017-03-17 17:44 ` Anton Ivanov
2 siblings, 1 reply; 8+ messages in thread
From: Richard Weinberger @ 2017-03-17 17:33 UTC (permalink / raw)
To: Anton Ivanov; +Cc: user-mode-linux-devel@lists.sourceforge.net
Am 17.03.2017 um 18:04 schrieb Anton Ivanov:
> On 17/03/17 16:56, Richard Weinberger wrote:
>> Anton,
>>
>> On Fri, Mar 17, 2017 at 8:51 AM, Anton Ivanov
>> <anton.ivanov@kot-begemot.co.uk> wrote:
>>> Hi list, hi Richard
>>>
>>> There is an extra check in mm/mmap.c which now throws a WARN on every
>>> page in making UML unusable with the latest 4.11-rc2
>> Which WARN? Can you find the offending commit?
>
> mm/mmap.c line 1112
Okay, this triggers since:
commit e86f15ee64d8ee46255d964d55f74f5ba9af8c36
Author: Andrea Arcangeli <aarcange@redhat.com>
Date: Fri Oct 7 17:01:28 2016 -0700
mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk
But you have to enable VM debugging to see it.
Thanks,
//richard
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [uml-devel] UML regression with latest RC 4.11-rc2
2017-03-17 17:33 ` Richard Weinberger
@ 2017-03-17 17:44 ` Anton Ivanov
2017-03-17 17:54 ` Richard Weinberger
0 siblings, 1 reply; 8+ messages in thread
From: Anton Ivanov @ 2017-03-17 17:44 UTC (permalink / raw)
To: Richard Weinberger; +Cc: user-mode-linux-devel@lists.sourceforge.net
On 17/03/17 17:33, Richard Weinberger wrote:
> Am 17.03.2017 um 18:04 schrieb Anton Ivanov:
>> On 17/03/17 16:56, Richard Weinberger wrote:
>>> Anton,
>>>
>>> On Fri, Mar 17, 2017 at 8:51 AM, Anton Ivanov
>>> <anton.ivanov@kot-begemot.co.uk> wrote:
>>>> Hi list, hi Richard
>>>>
>>>> There is an extra check in mm/mmap.c which now throws a WARN on every
>>>> page in making UML unusable with the latest 4.11-rc2
>>> Which WARN? Can you find the offending commit?
>> mm/mmap.c line 1112
> Okay, this triggers since:
>
> commit e86f15ee64d8ee46255d964d55f74f5ba9af8c36
> Author: Andrea Arcangeli <aarcange@redhat.com>
> Date: Fri Oct 7 17:01:28 2016 -0700
>
> mm: vma_merge: fix vm_page_prot SMP race condition against rmap_walk
>
> But you have to enable VM debugging to see it.
I have most debugging enabled to make sure I do not introduce any
re-entrancy in the IRQ handlers and/or have any allocations of the wrong
type where they do not belong.
We should probably submit a short patch #ifdef to turn this WARN() off
for UML
Brgds,
A.
>
> Thanks,
> //richard
>
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [uml-devel] UML regression with latest RC 4.11-rc2
2017-03-17 17:44 ` Anton Ivanov
@ 2017-03-17 17:54 ` Richard Weinberger
0 siblings, 0 replies; 8+ messages in thread
From: Richard Weinberger @ 2017-03-17 17:54 UTC (permalink / raw)
To: Anton Ivanov; +Cc: user-mode-linux-devel@lists.sourceforge.net
Anton,
Am 17.03.2017 um 18:44 schrieb Anton Ivanov:
>> But you have to enable VM debugging to see it.
>
> I have most debugging enabled to make sure I do not introduce any
> re-entrancy in the IRQ handlers and/or have any allocations of the wrong
> type where they do not belong.
>
> We should probably submit a short patch #ifdef to turn this WARN() off
> for UML
Not before we understand the root cause. :)
Thanks,
//richard
------------------------------------------------------------------------------
Check out the vibrant tech community on one of the world's most
engaging tech sites, Slashdot.org! http://sdm.link/slashdot
_______________________________________________
User-mode-linux-devel mailing list
User-mode-linux-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
^ permalink raw reply [flat|nested] 8+ messages in thread