The patch titled
Date: Fri, 15 Sep 2023 09:59:52 -0400
has been added to the -mm mm-unstable branch. Its filename is
mm-page_alloc-remove-pcppage-migratetype-caching-fix.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-remove-pcppage-migratetype-caching-fix.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: Johannes Weiner <hannes@xxxxxxxxxxx>
Date: Fri, 15 Sep 2023 09:59:52 -0400
Subject: mm-page_alloc-remove-pcppage-migratetype-caching-fix
Mike reports the following crash in -next:
[ 28.643019] page:ffffea0004fb4280 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x13ed0a
[ 28.645455] flags: 0x200000000000000(node=0|zone=2)
[ 28.646835] page_type: 0xffffffff()
[ 28.647886] raw: 0200000000000000 dead000000000100 dead000000000122 0000000000000000
[ 28.651170] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000
[ 28.653124] page dumped because: VM_BUG_ON_PAGE(is_migrate_isolate(mt))
[ 28.654769] ------------[ cut here ]------------
[ 28.655972] kernel BUG at mm/page_alloc.c:1231!
This VM_BUG_ON() used to check that the cached pcppage_migratetype set by
free_unref_page() wasn't MIGRATE_ISOLATE.
When I removed the caching, I erroneously changed the assert to check that
no isolated pages are on the pcplist. This is quite different, because
pages can be isolated *after* they had been put on the freelist already
(which is handled just fine).
IOW, this was purely a sanity check on the migratetype caching. With that
gone, the check should have been removed as well. Do that now.
Link: https://lkml.kernel.org/r/20230915141610.GA104956@xxxxxxxxxxx
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reported-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 3 ---
1 file changed, 3 deletions(-)
--- a/mm/page_alloc.c~mm-page_alloc-remove-pcppage-migratetype-caching-fix
+++ a/mm/page_alloc.c
@@ -1201,9 +1201,6 @@ static void free_pcppages_bulk(struct zo
count -= nr_pages;
pcp->count -= nr_pages;
- /* MIGRATE_ISOLATE page should not go to pcplists */
- VM_BUG_ON_PAGE(is_migrate_isolate(mt), page);
-
__free_one_page(page, pfn, zone, order, mt, FPI_NONE);
trace_mm_page_pcpu_drain(page, order, mt);
} while (count > 0 && !list_empty(list));
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
mm-page_alloc-fix-cma-and-highatomic-landing-on-the-wrong-buddy-list.patch
mm-memcontrol-fix-gfp_nofs-recursion-in-memoryhigh-enforcement.patch
mm-page_alloc-remove-pcppage-migratetype-caching.patch
mm-page_alloc-remove-pcppage-migratetype-caching-fix.patch
mm-page_alloc-fix-up-block-types-when-merging-compatible-blocks.patch
mm-page_alloc-move-free-pages-when-converting-block-during-isolation.patch
mm-page_alloc-fix-move_freepages_block-range-error.patch
mm-page_alloc-fix-freelist-movement-during-block-conversion.patch
mm-page_alloc-consolidate-free-page-accounting.patch
