diff --git a/mm/mmap.c b/mm/mmap.c index 3520c39304ba..d2856590427c 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -257,8 +257,11 @@ SYSCALL_DEFINE1(brk, unsigned long, brk) */ mas_set(&mas, oldbrk); next = mas_find(&mas, newbrk - 1 + PAGE_SIZE + stack_guard_gap); - if (next && newbrk + PAGE_SIZE > vm_start_gap(next)) - goto out; + if (next) { + vma_start_write(next); + if (newbrk + PAGE_SIZE > vm_start_gap(next)) + goto out; + } brkvma = mas_prev(&mas, mm->start_brk); /* Ok, looks good - let it rip. */ @@ -1027,10 +1030,17 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm, if (vm_flags & VM_SPECIAL) return NULL; + if (prev) + vma_start_write(prev); next = find_vma(mm, prev ? prev->vm_end : 0); + if (next) + vma_start_write(next); mid = next; - if (next && next->vm_end == end) /* cases 6, 7, 8 */ + if (next && next->vm_end == end) { /* cases 6, 7, 8 */ next = find_vma(mm, next->vm_end); + if (next) + vma_start_write(next); + } /* verify some invariant that must be enforced by the caller */ VM_WARN_ON(prev && addr <= prev->vm_start); @@ -2216,6 +2226,7 @@ int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma, int err; validate_mm_mt(mm); + vma_start_write(vma); if (vma->vm_ops && vma->vm_ops->may_split) { err = vma->vm_ops->may_split(vma, addr); if (err) @@ -2590,6 +2601,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr, /* Attempt to expand an old mapping */ /* Check next */ + if (next) + vma_start_write(next); if (next && next->vm_start == end && !vma_policy(next) && can_vma_merge_before(next, vm_flags, NULL, file, pgoff+pglen, NULL_VM_UFFD_CTX, NULL)) { @@ -2599,6 +2612,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr, } /* Check prev */ + if (prev) + vma_start_write(prev); if (prev && prev->vm_end == addr && !vma_policy(prev) && (vma ? can_vma_merge_after(prev, vm_flags, vma->anon_vma, file, pgoff, vma->vm_userfaultfd_ctx, NULL) : @@ -2976,6 +2991,8 @@ static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *vma, if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT)) return -ENOMEM; + if (vma) + vma_start_write(vma); /* * Expand the existing vma if possible; Note that singular lists do not * occur after forking, so the expand will only happen on new VMAs.