Re: WARNING: at mm/mremap.c:211 move_page_tables in i386

[Naresh Kamboju]

On Sat, 11 Jul 2020 at 01:35, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> On Fri, Jul 10, 2020 at 10:48 AM Naresh Kamboju
> <naresh.kamboju@xxxxxxxxxx> wrote:

I have started bisecting this problem and found the first bad commit

commit 9f132f7e145506efc0744426cb338b18a54afc3b
Author: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
Date:   Thu Jan 3 15:28:41 2019 -0800

    mm: select HAVE_MOVE_PMD on x86 for faster mremap

    Moving page-tables at the PMD-level on x86 is known to be safe.  Enable
    this option so that we can do fast mremap when possible.

    Link: http://lkml.kernel.org/r/20181108181201.88826-4-joelaf@xxxxxxxxxx
    Signed-off-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
    Suggested-by: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
    Acked-by: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
    Cc: Julia Lawall <Julia.Lawall@xxxxxxx>
    Cc: Michal Hocko <mhocko@xxxxxxxxxx>
    Cc: William Kucharski <william.kucharski@xxxxxxxxxx>
    Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
    Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e260460210e1..6185d4f33296 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -172,6 +172,7 @@ config X86
  select HAVE_MEMBLOCK_NODE_MAP
  select HAVE_MIXED_BREAKPOINTS_REGS
  select HAVE_MOD_ARCH_SPECIFIC
+ select HAVE_MOVE_PMD
  select HAVE_NMI
  select HAVE_OPROFILE
  select HAVE_OPTPROBES


After reverting the above patch the reported kernel warning got fixed on
Linus mainline tree 5.8.0-rc4.

-- 
Linaro LKFT
https://lkft.linaro.org