Messages in this thread | | | From | Song Liu <> | Subject | Re: [PATCH] x86/mm/pti: in pti_clone_pgtable() don't increase addr by PUD_SIZE | Date | Tue, 20 Aug 2019 13:21:34 +0000 |
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> On Aug 20, 2019, at 4:16 AM, Thomas Gleixner <tglx@linutronix.de> wrote: > > On Tue, 20 Aug 2019, Peter Zijlstra wrote: >> What that code wants to do is skip to the end of the pud, a pmd_size >> increase will not do that. And right below this, there's a second >> instance of this exact pattern. >> >> Did I get the below right? >> >> --- >> diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c >> index b196524759ec..32b20b3cb227 100644 >> --- a/arch/x86/mm/pti.c >> +++ b/arch/x86/mm/pti.c >> @@ -330,12 +330,14 @@ pti_clone_pgtable(unsigned long start, unsigned long end, >> >> pud = pud_offset(p4d, addr); >> if (pud_none(*pud)) { >> + addr &= PUD_MASK; >> addr += PUD_SIZE; > > round_up(addr, PUD_SIZE);
I guess we need "round_up(addr + PMD_SIZE, PUD_SIZE)".
Thanks, Song
> > perhaps? > >> continue; >> } >> >> pmd = pmd_offset(pud, addr); >> if (pmd_none(*pmd)) { >> + addr &= PMD_MASK; >> addr += PMD_SIZE; >> continue; >> } >>
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