Hello Vitaly,

>_count member was renamed to _refcount in linux 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]>
>---
>Changes since 'v1':
>- Make '_refcount' the default [Atsushi Kumagai]

Good fix, I'll merge this into v1.6.1.

Thanks,
Atsushi Kumagai

>---
> makedumpfile.c | 26 +++++++++++++++++++++-----
> makedumpfile.h |  3 ++-
> 2 files changed, 23 insertions(+), 6 deletions(-)
>
>diff --git a/makedumpfile.c b/makedumpfile.c
>index 853b999..fd884d3 100644
>--- a/makedumpfile.c
>+++ b/makedumpfile.c
>@@ -1579,7 +1579,14 @@ get_structure_info(void)
>        */
>       SIZE_INIT(page, "page");
>       OFFSET_INIT(page.flags, "page", "flags");
>-      OFFSET_INIT(page._count, "page", "_count");
>+      OFFSET_INIT(page._refcount, "page", "_refcount");
>+      if (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE) {
>+              info->flag_use_count = TRUE;
>+              OFFSET_INIT(page._refcount, "page", "_count");
>+      } else {
>+              info->flag_use_count = FALSE;
>+      }
>+
>       OFFSET_INIT(page.mapping, "page", "mapping");
>       OFFSET_INIT(page._mapcount, "page", "_mapcount");
>       OFFSET_INIT(page.private, "page", "private");
>@@ -2044,7 +2051,7 @@ get_mem_type(void)
>
>       if ((SIZE(page) == NOT_FOUND_STRUCTURE)
>           || (OFFSET(page.flags) == NOT_FOUND_STRUCTURE)
>-          || (OFFSET(page._count) == NOT_FOUND_STRUCTURE)
>+          || (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE)
>           || (OFFSET(page.mapping) == NOT_FOUND_STRUCTURE)) {
>               ret = NOT_FOUND_MEMTYPE;
>       } else if ((((SYMBOL(node_data) != NOT_FOUND_SYMBOL)
>@@ -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_use_count)
>+              WRITE_MEMBER_OFFSET("page._count", page._refcount);
>+      else
>+              WRITE_MEMBER_OFFSET("page._refcount", page._refcount);
>       WRITE_MEMBER_OFFSET("page.mapping", page.mapping);
>       WRITE_MEMBER_OFFSET("page.lru", page.lru);
>       WRITE_MEMBER_OFFSET("page._mapcount", page._mapcount);
>@@ -2491,7 +2501,13 @@ read_vmcoreinfo(void)
>
>
>       READ_MEMBER_OFFSET("page.flags", page.flags);
>-      READ_MEMBER_OFFSET("page._count", page._count);
>+      READ_MEMBER_OFFSET("page._refcount", page._refcount);
>+      if (OFFSET(page._refcount) == NOT_FOUND_STRUCTURE) {
>+              info->flag_use_count = TRUE;
>+              READ_MEMBER_OFFSET("page._count", page._refcount);
>+      } else {
>+              info->flag_use_count = FALSE;
>+      }
>       READ_MEMBER_OFFSET("page.mapping", page.mapping);
>       READ_MEMBER_OFFSET("page.lru", page.lru);
>       READ_MEMBER_OFFSET("page._mapcount", page._mapcount);
>@@ -5615,7 +5631,7 @@ __exclude_unnecessary_pages(unsigned long mem_map,
>               pcache  = page_cache + (index_pg * SIZE(page));
>
>               flags   = ULONG(pcache + OFFSET(page.flags));
>-              _count  = UINT(pcache + OFFSET(page._count));
>+              _count  = UINT(pcache + OFFSET(page._refcount));
>               mapping = ULONG(pcache + OFFSET(page.mapping));
>
>               if (OFFSET(page.compound_order) != NOT_FOUND_STRUCTURE) {
>diff --git a/makedumpfile.h b/makedumpfile.h
>index 251d4bf..533e5b8 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_use_count;      /* _refcount is named _count in 
>struct page */
>       unsigned long   vaddr_for_vtop;      /* virtual address for debugging */
>       long            page_size;           /* size of page */
>       long            page_shift;
>@@ -1483,7 +1484,7 @@ struct size_table {
> struct offset_table {
>       struct page {
>               long    flags;
>-              long    _count;
>+              long    _refcount;
>               long    mapping;
>               long    lru;
>               long    _mapcount;
>--
>2.5.5


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