diff options
| author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-07-27 11:49:37 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-07-27 11:49:37 +0200 |
| commit | 65a9bde6ed484880987a6d88de6e372eca52059f (patch) | |
| tree | a192e1a8a54d334f457413f9c16041ffdf11533d /mm/mmap.c | |
| parent | 860e73b49cd933c708e3e1e1e07cdea81b6acd1c (diff) | |
| parent | 92ed301919932f777713b9172e525674157e983d (diff) | |
Merge 5.8-rc7 into char-misc-next
This should resolve the merge/build issues reported when trying to
create linux-next.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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); |