From: Jann Horn jannh@google.com
stable inclusion from stable-v4.19.259 commit 56fa5f3dd44a05a5eacd75ae9d00c5415046d371 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5UQH4 CVE: NA
--------------------------------
This is a stable-specific patch. I botched the stable-specific rewrite of commit b67fbebd4cf98 ("mmu_gather: Force tlb-flush VM_PFNMAP vmas"): As Hugh pointed out, unmap_region() actually operates on a list of VMAs, and the variable "vma" merely points to the first VMA in that list. So if we want to check whether any of the VMAs we're operating on is PFNMAP or MIXEDMAP, we have to iterate through the list and check each VMA.
Signed-off-by: Jann Horn jannh@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yongqiang Liu liuyongqiang13@huawei.com --- mm/mmap.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c index 8b5f3e45613e..0576cad8ccb6 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2898,6 +2898,7 @@ static void unmap_region(struct mm_struct *mm, { struct vm_area_struct *next = prev ? prev->vm_next : mm->mmap; struct mmu_gather tlb; + struct vm_area_struct *cur_vma;
lru_add_drain(); tlb_gather_mmu(&tlb, mm, start, end); @@ -2912,8 +2913,12 @@ static void unmap_region(struct mm_struct *mm, * concurrent flush in this region has to be coming through the rmap, * and we synchronize against that using the rmap lock. */ - if ((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) != 0) - tlb_flush_mmu(&tlb); + for (cur_vma = vma; cur_vma; cur_vma = cur_vma->vm_next) { + if ((cur_vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) != 0) { + tlb_flush_mmu(&tlb); + break; + } + }
free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, next ? next->vm_start : USER_PGTABLES_CEILING);