Hello Dominik Dingel,
This is a semi-automatic email about new static checker warnings.
The patch 7d735b9ae82d: "s390/mm: hugetlb pages within a gmap can not
be freed" from Jul 13, 2018, leads to the following Smatch complaint:
arch/s390/mm/gmap.c:718 gmap_discard()
error: we previously assumed 'vma' could be null (see line 715)
arch/s390/mm/gmap.c
700 for (gaddr = from; gaddr < to;
701 gaddr = (gaddr + PMD_SIZE) & PMD_MASK) {
702 /* Find the vm address for the guest address */
703 vmaddr = (unsigned long)
704 radix_tree_lookup(&gmap->guest_to_host,
705 gaddr >> PMD_SHIFT);
706 if (!vmaddr)
707 continue;
708 vmaddr |= gaddr & ~PMD_MASK;
709 /* Find vma in the parent mm */
710 vma = find_vma(gmap->mm, vmaddr);
711 /*
712 * We do not discard pages that are backed by
713 * hugetlbfs, so we don't have to refault them.
714 */
715 if (vma && is_vm_hugetlb_page(vma))
^^^
The patch adds a new check
716 continue;
717 size = min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK));
718 zap_page_range(vma, vmaddr, size);
^^^
but if "vma" is NULL we are toasted here anyway.
719 }
720 up_read(&gmap->mm->mmap_sem);
regards,
dan carpenter
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