Hey SJ,
Thanks a lot for reporting!
On Tue, Apr 30, 2024 at 4:20 AM SeongJae Park <sj@xxxxxxxxxx> wrote:
>
> Hi Lance,
>
> On Mon, 29 Apr 2024 21:23:07 +0800 Lance Yang <ioworker0@xxxxxxxxx> wrote:
>
> > In preparation for supporting try_to_unmap_one() to unmap PMD-mapped
> > folios, start the pagewalk first, then call split_huge_pmd_address()
> > to split the folio.
> >
> > Suggested-by: David Hildenbrand <david@xxxxxxxxxx>
> > Signed-off-by: Lance Yang <ioworker0@xxxxxxxxx>
> > ---
> > include/linux/huge_mm.h | 2 ++
> > mm/huge_memory.c | 42 +++++++++++++++++++++--------------------
> > mm/rmap.c | 26 +++++++++++++++++++------
> > 3 files changed, 44 insertions(+), 26 deletions(-)
> >
> [...]
> > diff --git a/mm/rmap.c b/mm/rmap.c
> > index 7e2575d669a9..e42f436c7ff3 100644
> > --- a/mm/rmap.c
> > +++ b/mm/rmap.c
> > @@ -1636,9 +1636,6 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
> > if (flags & TTU_SYNC)
> > pvmw.flags = PVMW_SYNC;
> >
> > - if (flags & TTU_SPLIT_HUGE_PMD)
> > - split_huge_pmd_address(vma, address, false, folio);
> > -
> > /*
> > * For THP, we have to assume the worse case ie pmd for invalidation.
> > * For hugetlb, it could be much worse if we need to do pud
> > @@ -1650,6 +1647,10 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
> > range.end = vma_address_end(&pvmw);
> > mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm,
> > address, range.end);
> > + if (flags & TTU_SPLIT_HUGE_PMD) {
> > + range.start = address & HPAGE_PMD_MASK;
> > + range.end = (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE;
> > + }
>
> I found the latest mm-unstable fails one[1] of my build configuration
> with below error message. And 'git bisect' points this patch.
Thanks for taking time to 'git bisect' and identify this bug!
>
> CC mm/rmap.o
> In file included from <command-line>:
> .../linux/mm/rmap.c: In function 'try_to_unmap_one':
> .../linux/include/linux/compiler_types.h:460:38: error: call to '__compiletime_assert_455' declared with attribute error: BUILD_BUG failed
> 460 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> | ^
> .../linux/include/linux/compiler_types.h:441:4: note: in definition of macro '__compiletime_assert'
> 441 | prefix ## suffix(); \
> | ^~~~~~
> .../linux/include/linux/compiler_types.h:460:2: note: in expansion of macro '_compiletime_assert'
> 460 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
> | ^~~~~~~~~~~~~~~~~~~
> .../linux/include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
> 39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
> | ^~~~~~~~~~~~~~~~~~
> .../linux/include/linux/build_bug.h:59:21: note: in expansion of macro 'BUILD_BUG_ON_MSG'
> 59 | #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
> | ^~~~~~~~~~~~~~~~
> .../linux/include/linux/huge_mm.h:97:28: note: in expansion of macro 'BUILD_BUG'
> 97 | #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
> | ^~~~~~~~~
> .../linux/include/linux/huge_mm.h:104:34: note: in expansion of macro 'HPAGE_PMD_SHIFT'
> 104 | #define HPAGE_PMD_SIZE ((1UL) << HPAGE_PMD_SHIFT)
> | ^~~~~~~~~~~~~~~
> .../linux/include/linux/huge_mm.h:103:27: note: in expansion of macro 'HPAGE_PMD_SIZE'
> 103 | #define HPAGE_PMD_MASK (~(HPAGE_PMD_SIZE - 1))
> | ^~~~~~~~~~~~~~
> .../linux/mm/rmap.c:1651:27: note: in expansion of macro 'HPAGE_PMD_MASK'
> 1651 | range.start = address & HPAGE_PMD_MASK;
> | ^~~~~~~~~~~~~~
>
> I haven't looked into the code yet, but seems this code need to handle
> CONFIG_PGTABLE_HAS_HUGE_LEAVES undefined case? May I ask your opinion?
>
> [1] https://github.com/awslabs/damon-tests/blob/next/corr/tests/build_arm64.sh
I'll fix this bug and rebuild using the config you've provided above.
Thanks again for reporting!
Lance
>
>
> Thanks,
> SJ
> [...]
