diff options
| -rw-r--r-- | mm/mremap.c | 25 |
1 files changed, 19 insertions, 6 deletions
diff --git a/mm/mremap.c b/mm/mremap.c index fe587c5d6591..930f65c315c0 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -1027,16 +1027,29 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, } /* - * Function vma_merge() is called on the extension we are adding to - * the already existing vma, vma_merge() will merge this extension with - * the already existing vma (expand operation itself) and possibly also - * with the next vma if it becomes adjacent to the expanded vma and - * otherwise compatible. + * Function vma_merge() is called on the extension we + * are adding to the already existing vma, vma_merge() + * will merge this extension with the already existing + * vma (expand operation itself) and possibly also with + * the next vma if it becomes adjacent to the expanded + * vma and otherwise compatible. + * + * However, vma_merge() can currently fail due to + * is_mergeable_vma() check for vm_ops->close (see the + * comment there). Yet this should not prevent vma + * expanding, so perform a simple expand for such vma. + * Ideally the check for close op should be only done + * when a vma would be actually removed due to a merge. */ - vma = vma_merge(mm, vma, extension_start, extension_end, + if (!vma->vm_ops || !vma->vm_ops->close) { + vma = vma_merge(mm, vma, extension_start, extension_end, vma->vm_flags, vma->anon_vma, vma->vm_file, extension_pgoff, vma_policy(vma), vma->vm_userfaultfd_ctx, anon_vma_name(vma)); + } else if (vma_adjust(vma, vma->vm_start, addr + new_len, + vma->vm_pgoff, NULL)) { + vma = NULL; + } if (!vma) { vm_unacct_memory(pages); ret = -ENOMEM; |