* Re: [PATCH] mm: get rid of WARN if failed to cow user pages
[not found] <20191225054227.gii6ctjkuddjnprs@xzhoux.usersys.redhat.com>
@ 2020-01-15 6:02 ` Dan Williams
2020-02-18 21:09 ` Jeff Moyer
0 siblings, 1 reply; 3+ messages in thread
From: Dan Williams @ 2020-01-15 6:02 UTC (permalink / raw)
To: Murphy Zhou
Cc: linux-nvdimm, Jia He, Linux MM, Shutemov, Kirill,
Linux Kernel Mailing List
[ drop Ross, add Kirill, linux-mm, and lkml ]
On Tue, Dec 24, 2019 at 9:42 PM Murphy Zhou <jencce.kernel@gmail.com> wrote:
>
> By running xfstests with fsdax enabled, generic/437 always hits this
> warning[1] since this commit:
>
> commit 83d116c53058d505ddef051e90ab27f57015b025
> Author: Jia He <justin.he@arm.com>
> Date: Fri Oct 11 22:09:39 2019 +0800
>
> mm: fix double page fault on arm64 if PTE_AF is cleared
>
> Looking at the test program[2] generic/437 uses, it's pretty easy
> to hit this warning. Remove this WARN as it seems not necessary.
This is not sufficient justification. Does this same test fail without
DAX? If not, why not? At a minimum you need to explain why this is not
indicating a problem.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] mm: get rid of WARN if failed to cow user pages
2020-01-15 6:02 ` [PATCH] mm: get rid of WARN if failed to cow user pages Dan Williams
@ 2020-02-18 21:09 ` Jeff Moyer
2020-02-19 1:58 ` Murphy Zhou
0 siblings, 1 reply; 3+ messages in thread
From: Jeff Moyer @ 2020-02-18 21:09 UTC (permalink / raw)
To: Dan Williams
Cc: Murphy Zhou, linux-nvdimm, Jia He, Linux MM, Shutemov, Kirill,
Linux Kernel Mailing List
Dan Williams <dan.j.williams@intel.com> writes:
> [ drop Ross, add Kirill, linux-mm, and lkml ]
>
> On Tue, Dec 24, 2019 at 9:42 PM Murphy Zhou <jencce.kernel@gmail.com> wrote:
>>
>> By running xfstests with fsdax enabled, generic/437 always hits this
>> warning[1] since this commit:
>>
>> commit 83d116c53058d505ddef051e90ab27f57015b025
>> Author: Jia He <justin.he@arm.com>
>> Date: Fri Oct 11 22:09:39 2019 +0800
>>
>> mm: fix double page fault on arm64 if PTE_AF is cleared
>>
>> Looking at the test program[2] generic/437 uses, it's pretty easy
>> to hit this warning. Remove this WARN as it seems not necessary.
>
> This is not sufficient justification. Does this same test fail without
> DAX? If not, why not? At a minimum you need to explain why this is not
> indicating a problem.
I ran into this, too, and Kirill has posted a patch[1] to fix the issue.
Note that it's a potential data corrupter, so just removing the warning
is NOT the right approach. :)
-Jeff
[1] https://lore.kernel.org/linux-mm/20200218154151.13349-1-kirill.shutemov@linux.intel.com/T/#u
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] mm: get rid of WARN if failed to cow user pages
2020-02-18 21:09 ` Jeff Moyer
@ 2020-02-19 1:58 ` Murphy Zhou
0 siblings, 0 replies; 3+ messages in thread
From: Murphy Zhou @ 2020-02-19 1:58 UTC (permalink / raw)
To: Jeff Moyer
Cc: Dan Williams, Murphy Zhou, linux-nvdimm, Jia He, Linux MM,
Shutemov, Kirill, Linux Kernel Mailing List
On Tue, Feb 18, 2020 at 04:09:30PM -0500, Jeff Moyer wrote:
> Dan Williams <dan.j.williams@intel.com> writes:
>
> > [ drop Ross, add Kirill, linux-mm, and lkml ]
> >
> > On Tue, Dec 24, 2019 at 9:42 PM Murphy Zhou <jencce.kernel@gmail.com> wrote:
> >>
> >> By running xfstests with fsdax enabled, generic/437 always hits this
> >> warning[1] since this commit:
> >>
> >> commit 83d116c53058d505ddef051e90ab27f57015b025
> >> Author: Jia He <justin.he@arm.com>
> >> Date: Fri Oct 11 22:09:39 2019 +0800
> >>
> >> mm: fix double page fault on arm64 if PTE_AF is cleared
> >>
> >> Looking at the test program[2] generic/437 uses, it's pretty easy
> >> to hit this warning. Remove this WARN as it seems not necessary.
> >
> > This is not sufficient justification. Does this same test fail without
> > DAX? If not, why not? At a minimum you need to explain why this is not
> > indicating a problem.
>
> I ran into this, too, and Kirill has posted a patch[1] to fix the issue.
> Note that it's a potential data corrupter, so just removing the warning
> is NOT the right approach. :)
Agree :) Thanks!
>
> -Jeff
>
> [1] https://lore.kernel.org/linux-mm/20200218154151.13349-1-kirill.shutemov@linux.intel.com/T/#u
>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-02-19 1:58 UTC | newest]
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2020-01-15 6:02 ` [PATCH] mm: get rid of WARN if failed to cow user pages Dan Williams
2020-02-18 21:09 ` Jeff Moyer
2020-02-19 1:58 ` Murphy Zhou
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