The patch titled Subject: mm/thp: fix deferred split queue not partially_mapped: fix has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-thp-fix-deferred-split-queue-not-partially_mapped-fix.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-thp-fix-deferred-split-queue-not-partially_mapped-fix.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Hugh Dickins <hughd@xxxxxxxxxx> Subject: mm/thp: fix deferred split queue not partially_mapped: fix Date: Sun, 10 Nov 2024 13:11:21 -0800 (PST) Though even more elusive than before, list_del corruption has still been seen on THP's deferred split queue. The idea in commit e66f3185fa04 was right, but its implementation wrong. The context omitted an important comment just before the critical test: "split_folio() removes folio from list on success." In ignoring that comment, when a THP split succeeded, the code went on to release the preceding safe folio, preserving instead an irrelevant (formerly head) folio: which gives no safety because it's not on the list. Fix the logic. Link: https://lkml.kernel.org/r/3c995a30-31ce-0998-1b9f-3a2cb9354c91@xxxxxxxxxx Fixes: e66f3185fa04 ("mm/thp: fix deferred split queue not partially_mapped") Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx> Acked-by: Usama Arif <usamaarif642@xxxxxxxxx> Reviewed-by: Zi Yan <ziy@xxxxxxxxxx> Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> Cc: Barry Song <baohua@xxxxxxxxxx> Cc: Chris Li <chrisl@xxxxxxxxxx> Cc: David Hildenbrand <david@xxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Nhat Pham <nphamcs@xxxxxxxxx> Cc: Ryan Roberts <ryan.roberts@xxxxxxx> Cc: Shakeel Butt <shakeel.butt@xxxxxxxxx> Cc: Wei Yang <richard.weiyang@xxxxxxxxx> Cc: Yang Shi <shy828301@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/huge_memory.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/mm/huge_memory.c~mm-thp-fix-deferred-split-queue-not-partially_mapped-fix +++ a/mm/huge_memory.c @@ -3790,7 +3790,9 @@ next: * in the case it was underused, then consider it used and * don't add it back to split_queue. */ - if (!did_split && !folio_test_partially_mapped(folio)) { + if (did_split) { + ; /* folio already removed from list */ + } else if (!folio_test_partially_mapped(folio)) { list_del_init(&folio->_deferred_list); removed++; } else { _ Patches currently in -mm which might be from hughd@xxxxxxxxxx are mm-thp-fix-deferred-split-queue-not-partially_mapped-fix.patch mm-delete-the-unused-put_pages_list.patch