> On Dec 3, 2019, at 6:02 AM, David Hildenbrand <david@xxxxxxxxxx> wrote: > > On 06.11.19 16:05, Steven Price wrote: >> On 06/11/2019 13:31, Qian Cai wrote: >>> >>> >>>> On Nov 4, 2019, at 2:35 PM, Qian Cai <cai@xxxxxx> wrote: >>>> >>>> On Fri, 2019-11-01 at 14:09 +0000, Steven Price wrote: >> [...] >>>>> Changes since v14: >>>>> https://lore.kernel.org/lkml/20191028135910.33253-1-steven.price@xxxxxxx/ >>>>> * Switch walk_page_range() into two functions, the existing >>>>> walk_page_range() now still requires VMAs (and treats areas without a >>>>> VMA as a 'hole'). The new walk_page_range_novma() ignores VMAs and >>>>> will report the actual page table layout. This fixes the previous >>>>> breakage of /proc/<pid>/pagemap >>>>> * New patch at the end of the series which reduces the 'level' numbers >>>>> by 1 to simplify the code slightly >>>>> * Added tags >>>> >>>> Does this new version also take care of this boot crash seen with v14? Suppose >>>> it is now breaking CONFIG_EFI_PGT_DUMP=y? The full config is, >>>> >>>> https://raw.githubusercontent.com/cailca/linux-mm/master/x86.config >>>> >>> >>> V15 is indeed DOA here. >> >> Thanks for finding this, it looks like EFI causes issues here. The below fixes >> this for me (booting in QEMU). >> >> Andrew: do you want me to send out the entire series again for this fix, or >> can you squash this into mm-pagewalk-allow-walking-without-vma.patch? >> >> Thanks, >> >> Steve >> >> ---8<--- >> diff --git a/mm/pagewalk.c b/mm/pagewalk.c >> index c7529dc4f82b..70dcaa23598f 100644 >> --- a/mm/pagewalk.c >> +++ b/mm/pagewalk.c >> @@ -90,7 +90,7 @@ static int walk_pmd_range(pud_t *pud, unsigned long addr, unsigned long end, >> split_huge_pmd(walk->vma, pmd, addr); >> if (pmd_trans_unstable(pmd)) >> goto again; >> - } else if (pmd_leaf(*pmd)) { >> + } else if (pmd_leaf(*pmd) || !pmd_present(*pmd)) { >> continue; >> } >> >> @@ -141,7 +141,7 @@ static int walk_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end, >> split_huge_pud(walk->vma, pud, addr); >> if (pud_none(*pud)) >> goto again; >> - } else if (pud_leaf(*pud)) { >> + } else if (pud_leaf(*pud) || !pud_present(*pud)) { >> continue; >> } >> >> > > Even with this fix, booting for me under QEMU fails. See > > https://lore.kernel.org/linux-mm/b7ce62f2-9a48-6e48-6685-003431e521aa@xxxxxxxxxx/ > Yes, for some reasons, this starts to crash on almost all arches here, so it might be worth for Andrew to revert those in the meantime while allowing Steven to rework.
