The patch titled
Subject: mm: Fix __dump_folio
has been added to the -mm mm-unstable branch. Its filename is
mm-add-__dump_folio-fix-2.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-2.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 (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: Fix __dump_folio
Date: Fri, 1 Mar 2024 16:11:20 -0500
Ryan Roberts reports that (if you have CONFIG_CMA enabled), calling
__dump_folio() will panic as we call is_migrate_cma_page() with a stack
copy of struct page, which gets passed to page_to_pfn().
Link: https://lkml.kernel.org/r/ZeJJegP8zM7S9GTy@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reported-by: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Aishwarya TCV <aishwarya.tcv@xxxxxxx>
Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
Cc: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mmzone.h | 3 +++
mm/debug.c | 4 +---
2 files changed, 4 insertions(+), 3 deletions(-)
--- a/include/linux/mmzone.h~mm-add-__dump_folio-fix-2
+++ a/include/linux/mmzone.h
@@ -76,9 +76,12 @@ extern const char * const migratetype_na
#ifdef CONFIG_CMA
# define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
# define is_migrate_cma_page(_page) (get_pageblock_migratetype(_page) == MIGRATE_CMA)
+# define is_migrate_cma_folio(folio, pfn) (MIGRATE_CMA == \
+ get_pfnblock_flags_mask(&folio->page, pfn, MIGRATETYPE_MASK))
#else
# define is_migrate_cma(migratetype) false
# define is_migrate_cma_page(_page) false
+# define is_migrate_cma_folio(folio, pfn) false
#endif
static inline bool is_migrate_movable(int mt)
--- a/mm/debug.c~mm-add-__dump_folio-fix-2
+++ a/mm/debug.c
@@ -55,7 +55,6 @@ static void __dump_folio(struct folio *f
unsigned long pfn, unsigned long idx)
{
struct address_space *mapping = folio_mapping(folio);
- bool page_cma;
int mapcount = 0;
char *type = "";
@@ -98,9 +97,8 @@ static void __dump_folio(struct folio *f
* state for debugging, it should be fine to accept a bit of
* inaccuracy here due to racing.
*/
- page_cma = is_migrate_cma_page(page);
pr_warn("%sflags: %pGp%s\n", type, &folio->flags,
- page_cma ? " CMA" : "");
+ is_migrate_cma_folio(folio, pfn) ? " CMA" : "");
pr_warn("page_type: %pGt\n", &folio->page.page_type);
print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
_
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-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
