+ mm-page_alloc-always-remove-pages-from-temporary-list.patch added to mm-unstable branch

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

The patch titled
     Subject: mm/page_alloc: always remove pages from temporary list
has been added to the -mm mm-unstable branch.  Its filename is
     mm-page_alloc-always-remove-pages-from-temporary-list.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-always-remove-pages-from-temporary-list.patch

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

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------------------------------------------------------
From: Mel Gorman <mgorman@techsingularity.net>
Subject: mm/page_alloc: always remove pages from temporary list
Date: Fri, 18 Nov 2022 10:17:13 +0000

Patch series "Leave IRQs enabled for per-cpu page allocations", v3.


This patch (of 2):

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.

Link: https://lkml.kernel.org/r/20221118101714.19590-1-mgorman@techsingularity.net
Link: https://lkml.kernel.org/r/20221118101714.19590-2-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reported-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_alloc.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/mm/page_alloc.c~mm-page_alloc-always-remove-pages-from-temporary-list
+++ a/mm/page_alloc.c
@@ -3568,6 +3568,8 @@ void free_unref_page_list(struct list_he
 	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)
_

Patches currently in -mm which might be from mgorman@techsingularity.net are

mm-page_alloc-always-remove-pages-from-temporary-list.patch
mm-page_alloc-leave-irqs-enabled-for-per-cpu-page-allocations.patch