Hello Pratyush,

>commit 2d070eab2e82 "mm: consider zone which is not fully populated to
>have holes" added a new flag SECTION_IS_ONLINE and therefore
>SECTION_MAP_MASK has been changed. We are not able to find correct
>mem_map in makedumpfile for kernel version v4.13-rc1 and onward because
>of the above kernel change.
>
>This patch fixes the MASK value keeping the code backward compatible
>
>Signed-off-by: Pratyush Anand <[email protected]>
>---
> makedumpfile.c | 5 ++++-
> makedumpfile.h | 4 +++-
> 2 files changed, 7 insertions(+), 2 deletions(-)
>
>diff --git a/makedumpfile.c b/makedumpfile.c
>index 30230a15a2e7..7350e5b5af95 100644
>--- a/makedumpfile.c
>+++ b/makedumpfile.c
>@@ -3304,7 +3304,10 @@ section_mem_map_addr(unsigned long addr)
>               return NOT_KV_ADDR;
>       }
>       map = ULONG(mem_section + OFFSET(mem_section.section_mem_map));
>-      map &= SECTION_MAP_MASK;
>+      if (info->kernel_version <= KERNEL_VERSION(4, 12, 0))

I think this condition should be "< KERNEL_VERSION(4, 13, 0)",
actually v4.12.7 doesn't have SECTION_IS_ONLINE.

Thanks,
Atsushi Kumagai

>+              map &= SECTION_MAP_MASK_4_12;
>+      else
>+              map &= SECTION_MAP_MASK;
>       free(mem_section);
>
>       return map;
>diff --git a/makedumpfile.h b/makedumpfile.h
>index 8a05794843fb..322f28c632b0 100644
>--- a/makedumpfile.h
>+++ b/makedumpfile.h
>@@ -183,7 +183,9 @@ isAnon(unsigned long mapping)
> #define SECTIONS_PER_ROOT()   (info->sections_per_root)
> #define SECTION_ROOT_MASK()   (SECTIONS_PER_ROOT() - 1)
> #define SECTION_NR_TO_ROOT(sec)       ((sec) / SECTIONS_PER_ROOT())
>-#define SECTION_MAP_LAST_BIT  (1UL<<2)
>+#define SECTION_IS_ONLINE     (1UL<<2)
>+#define SECTION_MAP_LAST_BIT  (1UL<<3)
>+#define SECTION_MAP_MASK_4_12 (~(SECTION_IS_ONLINE-1))
> #define SECTION_MAP_MASK      (~(SECTION_MAP_LAST_BIT-1))
> #define NR_SECTION_ROOTS()    divideup(num_section, SECTIONS_PER_ROOT())
> #define SECTION_NR_TO_PFN(sec)        ((sec) << PFN_SECTION_SHIFT())
>--
>2.9.4


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