diff options
Diffstat (limited to 'mm/vmalloc.c')
| -rw-r--r-- | mm/vmalloc.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index f2481cb..195de42 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -244,11 +244,21 @@ struct page *vmalloc_to_page(const void *vmalloc_addr) */ VIRTUAL_BUG_ON(!is_vmalloc_or_module_addr(vmalloc_addr)); + /* + * Don't dereference bad PUD or PMD (below) entries. This will also + * identify huge mappings, which we may encounter on architectures + * that define CONFIG_HAVE_ARCH_HUGE_VMAP=y. Such regions will be + * identified as vmalloc addresses by is_vmalloc_addr(), but are + * not [unambiguously] associated with a struct page, so there is + * no correct value to return for them. + */ if (!pgd_none(*pgd)) { pud_t *pud = pud_offset(pgd, addr); - if (!pud_none(*pud)) { + WARN_ON_ONCE(pud_bad(*pud)); + if (!pud_none(*pud) && !pud_bad(*pud)) { pmd_t *pmd = pmd_offset(pud, addr); - if (!pmd_none(*pmd)) { + WARN_ON_ONCE(pmd_bad(*pmd)); + if (!pmd_none(*pmd) && !pmd_bad(*pmd)) { pte_t *ptep, pte; ptep = pte_offset_map(pmd, addr); |