lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Wed, 7 Jun 2017 20:06:51 +0300 From: "Kirill A. Shutemov" <kirill@...temov.name> To: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com> Cc: jglisse@...hat.com, linux-mm@...ck.org, linux-kernel@...r.kernel.org, Andy Lutomirski <luto@...nel.org>, Ingo Molnar <mingo@...nel.org>, Logan Gunthorpe <logang@...tatee.com> Subject: Re: [PATCH] x86/mm/hotplug: fix BUG_ON() after hotremove by not freeing pud v2 On Wed, Jun 07, 2017 at 08:03:25PM +0300, Kirill A. Shutemov wrote: > On Wed, Jun 07, 2017 at 10:46:20AM -0400, jglisse@...hat.com wrote: > > From: Jérôme Glisse <jglisse@...hat.com> > > > > With commit af2cf278ef4f we no longer free pud so that we do not > > have synchronize all pgd on hotremove/vfree. But the new 5 level > > page table patchset reverted that for 4 level page table. > > > > This patch restore af2cf278ef4f and disable free_pud() if we are > > in the 4 level page table case thus avoiding BUG_ON() after hot- > > remove. > > > > af2cf278ef4f x86/mm/hotplug: Don't remove PGD entries in remove_pagetable() > > > > Changed since v1: > > - make free_pud() conditional on the number of page table > > level > > - improved commit message > > > > Signed-off-by: Jérôme Glisse <jglisse@...hat.com> > > Cc: Andy Lutomirski <luto@...nel.org> > > Cc: Ingo Molnar <mingo@...nel.org> > > Cc: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com> > > Cc: Logan Gunthorpe <logang@...tatee.com> > > > thus we now trigger a BUG_ON() l128 in sync_global_pgds() > > > > > > This patch remove free_pud() like in af2cf278ef4f > > --- > > arch/x86/mm/init_64.c | 11 +++++++++++ > > 1 file changed, 11 insertions(+) > > > > diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c > > index 95651dc..61028bc 100644 > > --- a/arch/x86/mm/init_64.c > > +++ b/arch/x86/mm/init_64.c > > @@ -771,6 +771,16 @@ static void __meminit free_pmd_table(pmd_t *pmd_start, pud_t *pud) > > spin_unlock(&init_mm.page_table_lock); > > } > > > > +/* > > + * For 4 levels page table we do not want to free puds but for 5 levels > > + * we should free them. This code also need to change to adapt for boot > > + * time switching between 4 and 5 level. > > + */ > > +#if CONFIG_PGTABLE_LEVELS == 4 > > +static inline void free_pud_table(pud_t *pud_start, p4d_t *p4d) > > +{ > > +} > > Just "if (CONFIG_PGTABLE_LEVELS > 4)" before calling free_pud_table(), but > okay -- I'll rework it anyway for boot-time switching. Err. "if (CONFIG_PGTABLE_LEVELS == 4)" obviously. -- Kirill A. Shutemov
Powered by blists - more mailing lists