* linux-next: build failure after merge of the final tree
@ 2011-12-17 4:22 Stephen Rothwell
2011-12-17 4:27 ` Stephen Rothwell
2011-12-19 17:38 ` [PATCH] mm: Fix BUILD_BUG assertion in pmdp_clear_flush_young() David Daney
0 siblings, 2 replies; 6+ messages in thread
From: Stephen Rothwell @ 2011-12-17 4:22 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-next, linux-kernel, David Daney, Paul Mundt
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Hi ,
After merging the final tree, today's linux-next build (sh
edosk7705_defconfig and lots of other sh configs) failed like this:
mm/pgtable-generic.c: In function 'pmdp_clear_flush_young':
mm/pgtable-generic.c:76: error: call to '__build_bug_failed' declared with attribute error: BUILD_BUG failed
This is the
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
in pmdp_clear_flush_young().
Exposed by commit 835cea45a4a0 ("hugetlb: replace BUG() with BUILD_BUG()
for dummy definitions") from the akpm tree but I don't know the root
cause.
This may have a fix somewhere (if it is sh specific) but the current sh
tree in linux-next
(git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6.git) does
not exist.
--
Cheers,
Stephen Rothwell sfr@canb.auug.org.au
http://www.canb.auug.org.au/~sfr/
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^ permalink raw reply [flat|nested] 6+ messages in thread* Re: linux-next: build failure after merge of the final tree
2011-12-17 4:22 linux-next: build failure after merge of the final tree Stephen Rothwell
@ 2011-12-17 4:27 ` Stephen Rothwell
2011-12-19 17:38 ` [PATCH] mm: Fix BUILD_BUG assertion in pmdp_clear_flush_young() David Daney
1 sibling, 0 replies; 6+ messages in thread
From: Stephen Rothwell @ 2011-12-17 4:27 UTC (permalink / raw)
To: Andrew Morton; +Cc: linux-next, linux-kernel, David Daney, Paul Mundt
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Hi,
On Sat, 17 Dec 2011 15:22:53 +1100 Stephen Rothwell <sfr@canb.auug.org.au> wrote:
>
> After merging the final tree, today's linux-next build (sh
> edosk7705_defconfig and lots of other sh configs) failed like this:
>
> mm/pgtable-generic.c: In function 'pmdp_clear_flush_young':
> mm/pgtable-generic.c:76: error: call to '__build_bug_failed' declared with attribute error: BUILD_BUG failed
>
> This is the
>
> VM_BUG_ON(address & ~HPAGE_PMD_MASK);
>
> in pmdp_clear_flush_young().
>
> Exposed by commit 835cea45a4a0 ("hugetlb: replace BUG() with BUILD_BUG()
> for dummy definitions") from the akpm tree but I don't know the root
> cause.
>
> This may have a fix somewhere (if it is sh specific) but the current sh
> tree in linux-next
> (git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6.git) does
> not exist.
We are getting the same for all the cris config builds.
--
Cheers,
Stephen Rothwell sfr@canb.auug.org.au
http://www.canb.auug.org.au/~sfr/
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^ permalink raw reply [flat|nested] 6+ messages in thread* [PATCH] mm: Fix BUILD_BUG assertion in pmdp_clear_flush_young()
2011-12-17 4:22 linux-next: build failure after merge of the final tree Stephen Rothwell
2011-12-17 4:27 ` Stephen Rothwell
@ 2011-12-19 17:38 ` David Daney
2011-12-19 19:29 ` David Rientjes
1 sibling, 1 reply; 6+ messages in thread
From: David Daney @ 2011-12-19 17:38 UTC (permalink / raw)
To: Andrew Morton, Stephen Rothwell, Paul Mundt
Cc: linux-kernel, David Rientjes, David Daney
From: David Daney <david.daney@cavium.com>
It has been reported that when building for sh:
mm/pgtable-generic.c: In function 'pmdp_clear_flush_young':
mm/pgtable-generic.c:76: error: call to '__build_bug_failed' declared with attribute error: BUILD_BUG failed
Adding some ugle #ifdeffery will probably fix this issue.
Signed-off-by: David Daney <david.daney@cavium.com>
---
This is completely untested, but may be the best fix for this. Linus
and others have expressed a dislike for using BUG() to detect what
should be dead code paths at runtime, but it seems to be the state of
the art here.
mm/pgtable-generic.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index eb663fb..73784c8 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -70,7 +70,7 @@ int pmdp_clear_flush_young(struct vm_area_struct *vma,
unsigned long address, pmd_t *pmdp)
{
int young;
-#ifndef CONFIG_TRANSPARENT_HUGEPAGE
+#if !defined(CONFIG_HUGETLB_PAGE) || !defined(CONFIG_TRANSPARENT_HUGEPAGE)
BUG();
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
--
1.7.2.3
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] mm: Fix BUILD_BUG assertion in pmdp_clear_flush_young()
2011-12-19 17:38 ` [PATCH] mm: Fix BUILD_BUG assertion in pmdp_clear_flush_young() David Daney
@ 2011-12-19 19:29 ` David Rientjes
2011-12-19 19:52 ` David Daney
0 siblings, 1 reply; 6+ messages in thread
From: David Rientjes @ 2011-12-19 19:29 UTC (permalink / raw)
To: David Daney
Cc: Andrew Morton, Stephen Rothwell, Paul Mundt, linux-kernel, David Daney
On Mon, 19 Dec 2011, David Daney wrote:
> From: David Daney <david.daney@cavium.com>
>
> It has been reported that when building for sh:
>
> mm/pgtable-generic.c: In function 'pmdp_clear_flush_young':
> mm/pgtable-generic.c:76: error: call to '__build_bug_failed' declared with attribute error: BUILD_BUG failed
>
> Adding some ugle #ifdeffery will probably fix this issue.
>
It won't, CONFIG_HUGETLB_PAGE has nothing at all to do with this.
> Signed-off-by: David Daney <david.daney@cavium.com>
> ---
>
> This is completely untested, but may be the best fix for this. Linus
> and others have expressed a dislike for using BUG() to detect what
> should be dead code paths at runtime, but it seems to be the state of
> the art here.
>
The problem here is that HPAGE_PMD_MASK is being referenced without
CONFIG_TRANSPARENT_HUGEPAGE. pmdp_clear_flush_young() is only applicable
with that config option enabled. So rather than trying to minimize lines
captured under an #ifdef by placing the BUG() directly in the function for
asm-generic, you'll need to wrap pmd_clear_flush_young() with
#ifdef CONFIG_TRANSPARENT_HUGEPAGE and define its equivalent for
CONFIG_TRANSPARENT_HUGEPAGE=n that breaks the build if not enabled.
> mm/pgtable-generic.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
> index eb663fb..73784c8 100644
> --- a/mm/pgtable-generic.c
> +++ b/mm/pgtable-generic.c
> @@ -70,7 +70,7 @@ int pmdp_clear_flush_young(struct vm_area_struct *vma,
> unsigned long address, pmd_t *pmdp)
> {
> int young;
> -#ifndef CONFIG_TRANSPARENT_HUGEPAGE
> +#if !defined(CONFIG_HUGETLB_PAGE) || !defined(CONFIG_TRANSPARENT_HUGEPAGE)
> BUG();
> #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
> VM_BUG_ON(address & ~HPAGE_PMD_MASK);
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] mm: Fix BUILD_BUG assertion in pmdp_clear_flush_young()
2011-12-19 19:29 ` David Rientjes
@ 2011-12-19 19:52 ` David Daney
2011-12-19 20:34 ` David Rientjes
0 siblings, 1 reply; 6+ messages in thread
From: David Daney @ 2011-12-19 19:52 UTC (permalink / raw)
To: David Rientjes
Cc: Andrew Morton, Stephen Rothwell, Paul Mundt, linux-kernel, David Daney
On 12/19/2011 11:29 AM, David Rientjes wrote:
> On Mon, 19 Dec 2011, David Daney wrote:
>
>> From: David Daney<david.daney@cavium.com>
>>
>> It has been reported that when building for sh:
>>
>> mm/pgtable-generic.c: In function 'pmdp_clear_flush_young':
>> mm/pgtable-generic.c:76: error: call to '__build_bug_failed' declared with attribute error: BUILD_BUG failed
>>
>> Adding some ugle #ifdeffery will probably fix this issue.
>>
>
> It won't, CONFIG_HUGETLB_PAGE has nothing at all to do with this.
>
Sorry for the noise. You are correct.
>> Signed-off-by: David Daney<david.daney@cavium.com>
>> ---
>>
>> This is completely untested, but may be the best fix for this. Linus
>> and others have expressed a dislike for using BUG() to detect what
>> should be dead code paths at runtime, but it seems to be the state of
>> the art here.
>>
>
> The problem here is that HPAGE_PMD_MASK is being referenced without
> CONFIG_TRANSPARENT_HUGEPAGE. pmdp_clear_flush_young() is only applicable
> with that config option enabled. So rather than trying to minimize lines
> captured under an #ifdef by placing the BUG() directly in the function for
> asm-generic, you'll need to wrap pmd_clear_flush_young() with
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE and define its equivalent for
> CONFIG_TRANSPARENT_HUGEPAGE=n that breaks the build if not enabled.
>
That does sound like a better option.
I still think having the BUILD_BUG defined as we do in Andrew Morton's
tree is the correct approach, and I don't want to see that reverted
because of this ugliness.
Really this is hackery that should be cleaned up as you suggest, instead
of being papered over with this BUG() thing. I can't test SH things,
otherwise I might look at it. The SH maintainers should probably take a
look instead.
David Daney
>> mm/pgtable-generic.c | 2 +-
>> 1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
>> index eb663fb..73784c8 100644
>> --- a/mm/pgtable-generic.c
>> +++ b/mm/pgtable-generic.c
>> @@ -70,7 +70,7 @@ int pmdp_clear_flush_young(struct vm_area_struct *vma,
>> unsigned long address, pmd_t *pmdp)
>> {
>> int young;
>> -#ifndef CONFIG_TRANSPARENT_HUGEPAGE
>> +#if !defined(CONFIG_HUGETLB_PAGE) || !defined(CONFIG_TRANSPARENT_HUGEPAGE)
>> BUG();
>> #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>> VM_BUG_ON(address& ~HPAGE_PMD_MASK);
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] mm: Fix BUILD_BUG assertion in pmdp_clear_flush_young()
2011-12-19 19:52 ` David Daney
@ 2011-12-19 20:34 ` David Rientjes
0 siblings, 0 replies; 6+ messages in thread
From: David Rientjes @ 2011-12-19 20:34 UTC (permalink / raw)
To: David Daney
Cc: Andrew Morton, Stephen Rothwell, Paul Mundt, linux-kernel, David Daney
On Mon, 19 Dec 2011, David Daney wrote:
> > The problem here is that HPAGE_PMD_MASK is being referenced without
> > CONFIG_TRANSPARENT_HUGEPAGE. pmdp_clear_flush_young() is only applicable
> > with that config option enabled. So rather than trying to minimize lines
> > captured under an #ifdef by placing the BUG() directly in the function for
> > asm-generic, you'll need to wrap pmd_clear_flush_young() with
> > #ifdef CONFIG_TRANSPARENT_HUGEPAGE and define its equivalent for
> > CONFIG_TRANSPARENT_HUGEPAGE=n that breaks the build if not enabled.
> >
>
> That does sound like a better option.
>
> I still think having the BUILD_BUG defined as we do in Andrew Morton's tree is
> the correct approach, and I don't want to see that reverted because of this
> ugliness.
>
Agreed, the problem here is that we have existing code, such as
pmdp_clear_flush_young() that is calling BUG() at runtime for
non-supported configurations. So when BUILD_BUG_ON() for HPAGE_PMD_MASK
and friends was introduced, it detects improper use that needs to be fixed
and you've found one of those cases.
> Really this is hackery that should be cleaned up as you suggest, instead of
> being papered over with this BUG() thing. I can't test SH things, otherwise I
> might look at it. The SH maintainers should probably take a look instead.
>
It's not only about sh, this will affect any architecture that uses the
generic version of pmdp_clear_flush_young(), which is everything except
x86.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2011-12-19 20:34 UTC | newest]
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2011-12-17 4:22 linux-next: build failure after merge of the final tree Stephen Rothwell
2011-12-17 4:27 ` Stephen Rothwell
2011-12-19 17:38 ` [PATCH] mm: Fix BUILD_BUG assertion in pmdp_clear_flush_young() David Daney
2011-12-19 19:29 ` David Rientjes
2011-12-19 19:52 ` David Daney
2011-12-19 20:34 ` David Rientjes
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