The patch titled
Subject: mm-add-__dump_folio-fix-3
has been added to the -mm mm-unstable branch. Its filename is
mm-add-__dump_folio-fix-3.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-add-__dump_folio-fix-3.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: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Subject: mm-add-__dump_folio-fix-3
Date: Mon, 4 Mar 2024 19:02:43 +0000
Further testing revealed some more problems. We were getting confused
between various different pointers leading to spurious messages about
the page not matching the folio and passing the wrong pointer to
__dump_folio(). Here's a fix-3 patch which I tested like so:
+static int __init page_dump(void)
+{
+ struct page *page;
+
+ printk("testing page dump\n");
+
+ page = alloc_page(GFP_KERNEL);
+ dump_page(page, "single");
+ put_page(page);
+ page = alloc_pages(GFP_KERNEL | __GFP_COMP, 2);
+ dump_page(page, "head");
+ dump_page(page + 1, "tail 1");
+ dump_page(page + 2, "tail 2");
+ dump_page(page + 3, "tail 3");
+ put_page(page);
+
+ return 0;
+}
+
+module_init(page_dump);
(needed some extra debug to check the values of the pointers being
passed to __dump_folio() which we wouldn't want to include)
Link: https://lkml.kernel.org/r/ZeYa00ixxC4k1ot-@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Aishwarya TCV <aishwarya.tcv@xxxxxxx>
Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/debug.c | 36 ++++++++++++++++++++++--------------
1 file changed, 22 insertions(+), 14 deletions(-)
--- a/mm/debug.c~mm-add-__dump_folio-fix-3
+++ a/mm/debug.c
@@ -121,23 +121,31 @@ static void __dump_page(const struct pag
again:
memcpy(&precise, page, sizeof(*page));
foliop = page_folio(&precise);
- idx = folio_page_idx(foliop, page);
- if (idx != 0) {
- if (idx < MAX_FOLIO_NR_PAGES) {
- memcpy(&folio, foliop, 2 * sizeof(struct page));
- nr_pages = folio_nr_pages(&folio);
- }
+ if (foliop == (struct folio *)&precise) {
+ idx = 0;
+ if (!folio_test_large(foliop))
+ goto dump;
+ foliop = (struct folio *)page;
+ } else {
+ idx = folio_page_idx(foliop, page);
+ }
+
+ if (idx < MAX_FOLIO_NR_PAGES) {
+ memcpy(&folio, foliop, 2 * sizeof(struct page));
+ nr_pages = folio_nr_pages(&folio);
+ foliop = &folio;
+ }
- if (idx > nr_pages) {
- if (loops-- > 0)
- goto again;
- printk("page does not match folio\n");
- precise.compound_head &= ~1UL;
- foliop = (struct folio *)&precise;
- idx = 0;
- }
+ if (idx > nr_pages) {
+ if (loops-- > 0)
+ goto again;
+ printk("page does not match folio\n");
+ precise.compound_head &= ~1UL;
+ foliop = (struct folio *)&precise;
+ idx = 0;
}
+dump:
__dump_folio(foliop, &precise, pfn, idx);
}
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-support-order-1-folios-in-the-page-cache.patch
mm-make-folios_put-the-basis-of-release_pages.patch
mm-convert-free_unref_page_list-to-use-folios.patch
mm-add-free_unref_folios.patch
mm-use-folios_put-in-__folio_batch_release.patch
memcg-add-mem_cgroup_uncharge_folios.patch
mm-remove-use-of-folio-list-from-folios_put.patch
mm-use-free_unref_folios-in-put_pages_list.patch
mm-use-__page_cache_release-in-folios_put.patch
mm-handle-large-folios-in-free_unref_folios.patch
mm-allow-non-hugetlb-large-folios-to-be-batch-processed.patch
mm-free-folios-in-a-batch-in-shrink_folio_list.patch
mm-free-folios-directly-in-move_folios_to_lru.patch
memcg-remove-mem_cgroup_uncharge_list.patch
mm-remove-free_unref_page_list.patch
mm-remove-lru_to_page.patch
mm-convert-free_pages_and_swap_cache-to-use-folios_put.patch
mm-use-a-folio-in-__collapse_huge_page_copy_succeeded.patch
mm-convert-free_swap_cache-to-take-a-folio.patch
mm-use-folio-more-widely-in-__split_huge_page.patch
mm-separate-out-folio_flags-from-pageflags.patch
mm-remove-pagewaiters-pagesetwaiters-and-pageclearwaiters.patch
mm-remove-pageyoung-and-pageidle-definitions.patch
mm-add-__dump_folio.patch
mm-add-__dump_folio-fix.patch
mm-add-__dump_folio-fix-2.patch
mm-add-__dump_folio-fix-3.patch
mm-make-dump_page-take-a-const-argument.patch
mm-constify-testing-page-folio-flags.patch
mm-constify-more-page-folio-tests.patch
mm-remove-cast-from-page_to_nid.patch
mm-mempolicy-use-a-folio-in-do_mbind.patch
