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    SubjectRe: [PATCH 1/2] mm/page_alloc: Always remove pages from temporary list
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    On 11/18/22 11:17, Mel Gorman wrote:
    > free_unref_page_list() has neglected to remove pages properly from the list
    > of pages to free since forever. It works by coincidence because list_add
    > happened to do the right thing adding the pages to just the PCP lists.
    > However, a later patch added pages to either the PCP list or the zone list
    > but only properly deleted the page from the list in one path leading to
    > list corruption and a subsequent failure. As a preparation patch, always
    > delete the pages from one list properly before adding to another. On its
    > own, this fixes nothing although it adds a fractional amount of overhead
    > but is critical to the next patch.
    >
    > Reported-by: Hugh Dickins <hughd@google.com>
    > Signed-off-by: Mel Gorman <mgorman@techsingularity.net>

    Reviewed-by: Vlastimil Babka <vbabka@suse.cz>

    > ---
    > mm/page_alloc.c | 2 ++
    > 1 file changed, 2 insertions(+)
    >
    > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
    > index 218b28ee49ed..1ec54173b8d4 100644
    > --- a/mm/page_alloc.c
    > +++ b/mm/page_alloc.c
    > @@ -3546,6 +3546,8 @@ void free_unref_page_list(struct list_head *list)
    > list_for_each_entry_safe(page, next, list, lru) {
    > struct zone *zone = page_zone(page);
    >
    > + list_del(&page->lru);
    > +
    > /* Different zone, different pcp lock. */
    > if (zone != locked_zone) {
    > if (pcp)

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