Messages in this thread Patch in this message | | | From | Steven Price <> | Subject | Re: [PATCH v15 00/23] Generic page walk and ptdump | Date | Wed, 6 Nov 2019 15:05:29 +0000 |
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On 06/11/2019 13:31, Qian Cai wrote: > > >> On Nov 4, 2019, at 2:35 PM, Qian Cai <cai@lca.pw> 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@arm.com/ >>> * 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; }
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