+ mm-page_alloc-init-local-variable-buddy_pfn.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/page_alloc: init local variable buddy_pfn
has been added to the -mm mm-unstable branch.  Its filename is
     mm-page_alloc-init-local-variable-buddy_pfn.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_alloc-init-local-variable-buddy_pfn.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Miaohe Lin <linmiaohe@huawei.com>
Subject: mm/page_alloc: init local variable buddy_pfn
Date: Fri, 16 Sep 2022 15:22:54 +0800

The local variable buddy_pfn could be passed to buddy_merge_likely()
without initialization if the passed in order is MAX_ORDER - 1.  This
looks buggy but buddy_pfn won't be used in this case as there's a order >=
MAX_ORDER - 2 check.  Init buddy_pfn to 0 anyway to avoid possible future
misuse.

Link: https://lkml.kernel.org/r/20220916072257.9639-14-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_alloc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/page_alloc.c~mm-page_alloc-init-local-variable-buddy_pfn
+++ a/mm/page_alloc.c
@@ -1113,7 +1113,7 @@ static inline void __free_one_page(struc
 		int migratetype, fpi_t fpi_flags)
 {
 	struct capture_control *capc = task_capc(zone);
-	unsigned long buddy_pfn;
+	unsigned long buddy_pfn = 0;
 	unsigned long combined_pfn;
 	struct page *buddy;
 	bool to_tail;
_

Patches currently in -mm which might be from linmiaohe@huawei.com are

mm-hwpoison-use-clearpagehwpoison-in-memory_failure.patch
mm-hwpoison-use-__pagemovable-to-detect-non-lru-movable-pages.patch
mm-hwpoison-use-num_poisoned_pages_sub-to-decrease-num_poisoned_pages.patch
mm-hwpoison-avoid-unneeded-page_mapped_in_vma-overhead-in-collect_procs_anon.patch
mm-hwpoison-check-pagetable-explicitly-in-hwpoison_user_mappings.patch
mm-hwpoison-cleanup-some-obsolete-comments.patch
writeback-remove-unused-macro-dirty_full_scope.patch
mm-page_alloc-ensure-kswapd-doesnt-accidentally-go-to-sleep.patch
mm-page_alloc-make-zone_pcp_update-static.patch
mm-remove-obsolete-macro-nr_pcp_order_mask-and-nr_pcp_order_width.patch
mm-page_alloc-remove-obsolete-comment-in-zone_statistics.patch
mm-page_alloc-add-__init-annotations-to-init_mem_debugging_and_hardening.patch
mm-page_alloc-fix-freeing-static-percpu-memory.patch
mm-remove-obsolete-pgdat_is_empty.patch
mm-page_alloc-add-missing-is_migrate_isolate-check-in-set_page_guard.patch
mm-page_alloc-use-local-variable-zone_idx-directly.patch
mm-memory_hotplug-remove-obsolete-generic_free_nodedata.patch
mm-page_alloc-make-boot_nodestats-static.patch
mm-page_alloc-use-helper-macro-sz_1km.patch
mm-page_alloc-init-local-variable-buddy_pfn.patch
mm-page_alloc-use-costly_order-in-warn_on_once_gfp.patch
mm-page_alloc-remove-obsolete-gfpflags_normal_context.patch
mm-page_alloc-fix-obsolete-comment-in-deferred_pfn_valid.patch