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| author | Ingo Molnar <mingo@kernel.org> | 2020-07-31 11:58:05 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-07-31 12:16:09 +0200 |
| commit | 28cff52eaeb5c43144d0c730080aff0d6bc1e5d5 (patch) | |
| tree | a55a41b99503a5c96314908b9f30db37e301d64d /mm/mmap.c | |
| parent | 92c209ac6d3d35783c16c8a717547183e6e11162 (diff) | |
| parent | d8b9faec54ae4bc2fff68bcd0befa93ace8256ce (diff) | |
| download | lwn-28cff52eaeb5c43144d0c730080aff0d6bc1e5d5.tar.gz lwn-28cff52eaeb5c43144d0c730080aff0d6bc1e5d5.zip | |
Merge branch 'linus' into locking/core, to resolve conflict
Conflicts:
arch/arm/include/asm/percpu.h
As Stephen Rothwell noted, there's a conflict between this commit
in locking/core:
a21ee6055c30 ("lockdep: Change hardirq{s_enabled,_context} to per-cpu variables")
and this fresh upstream commit:
aa54ea903abb ("ARM: percpu.h: fix build error")
a21ee6055c30 is a simpler solution to the dependency problem and doesn't
further increase header hell - so this conflict resolution effectively
reverts aa54ea903abb and uses the a21ee6055c30 solution.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 16 |
1 files changed, 14 insertions, 2 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 59a4682ebf3f..8c7ca737a19b 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2620,7 +2620,7 @@ static void unmap_region(struct mm_struct *mm, * Create a list of vma's touched by the unmap, removing them from the mm's * vma list as we go.. */ -static void +static bool detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, struct vm_area_struct *prev, unsigned long end) { @@ -2645,6 +2645,17 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, /* Kill the cache */ vmacache_invalidate(mm); + + /* + * Do not downgrade mmap_lock if we are next to VM_GROWSDOWN or + * VM_GROWSUP VMA. Such VMAs can change their size under + * down_read(mmap_lock) and collide with the VMA we are about to unmap. + */ + if (vma && (vma->vm_flags & VM_GROWSDOWN)) + return false; + if (prev && (prev->vm_flags & VM_GROWSUP)) + return false; + return true; } /* @@ -2825,7 +2836,8 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len, } /* Detach vmas from rbtree */ - detach_vmas_to_be_unmapped(mm, vma, prev, end); + if (!detach_vmas_to_be_unmapped(mm, vma, prev, end)) + downgrade = false; if (downgrade) mmap_write_downgrade(mm); |