Hello Vitaly,

>_count member was renamed to _refcount in linux commit commit 0139aa7b7fa12
>("mm: rename _count, field of the struct page, to _refcount") and this
>broke makedumpfile. The reason for making the change was to find all users
>accessing it directly and not through the recommended API. I tried
>suggesting to revert the change but failed, I see no other choice than to
>start supporting both _count and _refcount in makedumpfile.
>
>Signed-off-by: Vitaly Kuznetsov <[email protected]>

Thanks for your report and fixing it.

>---
>- 'crash' tool is now broken as well.
>---
> makedumpfile.c | 18 +++++++++++++++++-
> makedumpfile.h |  1 +
> 2 files changed, 18 insertions(+), 1 deletion(-)
>
>diff --git a/makedumpfile.c b/makedumpfile.c
>index 853b999..96dfe39 100644
>--- a/makedumpfile.c
>+++ b/makedumpfile.c
>@@ -1580,6 +1580,13 @@ get_structure_info(void)
>       SIZE_INIT(page, "page");
>       OFFSET_INIT(page.flags, "page", "flags");
>       OFFSET_INIT(page._count, "page", "_count");
>+      if (OFFSET(page._count) == NOT_FOUND_STRUCTURE) {
>+              info->flag_refcount = TRUE;
>+              OFFSET_INIT(page._count, "page", "_refcount");
>+      } else {
>+              info->flag_refcount = FALSE;
>+      }
>+

I prefer to check the new symbol name first since it's likely
from now on.

>       OFFSET_INIT(page.mapping, "page", "mapping");
>       OFFSET_INIT(page._mapcount, "page", "_mapcount");
>       OFFSET_INIT(page.private, "page", "private");
>@@ -2151,7 +2158,10 @@ write_vmcoreinfo_data(void)
>        * write the member offset of 1st kernel
>        */
>       WRITE_MEMBER_OFFSET("page.flags", page.flags);
>-      WRITE_MEMBER_OFFSET("page._count", page._count);
>+      if (info->flag_refcount)
>+              WRITE_MEMBER_OFFSET("page._refcount", page._count);
>+      else
>+              WRITE_MEMBER_OFFSET("page._count", page._count);
>       WRITE_MEMBER_OFFSET("page.mapping", page.mapping);
>       WRITE_MEMBER_OFFSET("page.lru", page.lru);
>       WRITE_MEMBER_OFFSET("page._mapcount", page._mapcount);
>@@ -2492,6 +2502,12 @@ read_vmcoreinfo(void)
>
>       READ_MEMBER_OFFSET("page.flags", page.flags);
>       READ_MEMBER_OFFSET("page._count", page._count);
>+      if (OFFSET(page._count) == NOT_FOUND_STRUCTURE) {
>+              info->flag_refcount = TRUE;
>+              READ_MEMBER_OFFSET("page._refcount", page._count);
>+      } else {
>+              info->flag_refcount = FALSE;
>+      }

same as OFFSET_INIT.

Thanks,
Atsushi Kumagai

>       READ_MEMBER_OFFSET("page.mapping", page.mapping);
>       READ_MEMBER_OFFSET("page.lru", page.lru);
>       READ_MEMBER_OFFSET("page._mapcount", page._mapcount);
>diff --git a/makedumpfile.h b/makedumpfile.h
>index 251d4bf..3742389 100644
>--- a/makedumpfile.h
>+++ b/makedumpfile.h
>@@ -1100,6 +1100,7 @@ struct DumpInfo {
>       int             flag_nospace;        /* the flag of "No space on 
> device" error */
>       int             flag_vmemmap;        /* kernel supports vmemmap address 
> space */
>       int             flag_excludevm;      /* -e - excluding unused vmemmap 
> pages */
>+      int             flag_refcount;       /* _count is renamed to _refcount 
>*/
>       unsigned long   vaddr_for_vtop;      /* virtual address for debugging */
>       long            page_size;           /* size of page */
>       long            page_shift;
>--
>2.5.5

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