The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x f29623e4a599c295cc8f518c8e4bb7848581a14d # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2023081215-deduce-elective-a3f6@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

f29623e4a599 ("mm: memory-failure: fix potential unexpected return value from unpoison_memory()") a6fddef49eef ("mm/memory-failure: convert unpoison_memory() to folios") 9637d7dfb19c ("mm/memory-failure: convert free_raw_hwp_pages() to folios") 2ff6cecee669 ("mm/memory-failure: convert hugetlb_clear_page_hwpoison to folios") bc1cfde19467 ("mm/memory-failure: convert try_memory_failure_hugetlb() to folios") 911565b82853 ("mm/hugetlb: convert destroy_compound_gigantic_page() to folios") e0ff42804233 ("mm/memory-failure.c: cleanup in unpoison_memory") cb67f4282bf9 ("mm,thp,rmap: simplify compound page mapcount handling") dad6a5eb5556 ("mm,hugetlb: use folio fields in second tail page") f074732d599e ("mm/hugetlb_cgroup: convert hugetlb_cgroup_from_page() to folios") a098c977722c ("mm/hugetlb_cgroup: convert __set_hugetlb_cgroup() to folios") 5033091de814 ("mm/hwpoison: introduce per-memory_block hwpoison counter") a46c9304b4bb ("mm/hwpoison: pass pfn to num_poisoned_pages_*()") d027122d8363 ("mm/hwpoison: move definitions of num_poisoned_pages_* to memory-failure.c") e591ef7d96d6 ("mm,hwpoison,hugetlb,memory_hotplug: hotremove memory section with hwpoisoned hugepage") b66d00dfebe7 ("mm: memory-failure: make action_result() return int") 4781593d5dba ("mm/hugetlb: unify clearing of RestoreReserve for private pages") 149562f75094 ("mm/hugetlb: add hugetlb_folio_subpool() helpers") d340625f4849 ("mm: add private field of first tail to struct page and struct folio")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From f29623e4a599c295cc8f518c8e4bb7848581a14d Mon Sep 17 00:00:00 2001 From: Miaohe Lin linmiaohe@huawei.com Date: Thu, 27 Jul 2023 19:56:41 +0800 Subject: [PATCH] mm: memory-failure: fix potential unexpected return value from unpoison_memory()

If unpoison_memory() fails to clear page hwpoisoned flag, return value ret is expected to be -EBUSY. But when get_hwpoison_page() returns 1 and fails to clear page hwpoisoned flag due to races, return value will be unexpected 1 leading to users being confused. And there's a code smell that the variable "ret" is used not only to save the return value of unpoison_memory(), but also the return value from get_hwpoison_page(). Make a further cleanup by using another auto-variable solely to save the return value of get_hwpoison_page() as suggested by Naoya.

Link: https://lkml.kernel.org/r/20230727115643.639741-3-linmiaohe@huawei.com Fixes: bf181c582588 ("mm/hwpoison: fix unpoison_memory()") Signed-off-by: Miaohe Lin linmiaohe@huawei.com Cc: Kefeng Wang wangkefeng.wang@huawei.com Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: Naoya Horiguchi naoya.horiguchi@nec.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org

diff --git a/mm/memory-failure.c b/mm/memory-failure.c index ece5d481b5ff..b32d370b5d43 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -2466,7 +2466,7 @@ int unpoison_memory(unsigned long pfn) { struct folio *folio; struct page *p; - int ret = -EBUSY; + int ret = -EBUSY, ghp; unsigned long count = 1; bool huge = false; static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL, @@ -2514,29 +2514,28 @@ int unpoison_memory(unsigned long pfn) if (folio_test_slab(folio) || PageTable(&folio->page) || folio_test_reserved(folio)) goto unlock_mutex;

- ret = get_hwpoison_page(p, MF_UNPOISON); - if (!ret) { + ghp = get_hwpoison_page(p, MF_UNPOISON); + if (!ghp) { if (PageHuge(p)) { huge = true; count = folio_free_raw_hwp(folio, false); - if (count == 0) { - ret = -EBUSY; + if (count == 0) goto unlock_mutex; - } } ret = folio_test_clear_hwpoison(folio) ? 0 : -EBUSY; - } else if (ret < 0) { - if (ret == -EHWPOISON) { + } else if (ghp < 0) { + if (ghp == -EHWPOISON) { ret = put_page_back_buddy(p) ? 0 : -EBUSY; - } else + } else { + ret = ghp; unpoison_pr_info("Unpoison: failed to grab page %#lx\n", pfn, &unpoison_rs); + } } else { if (PageHuge(p)) { huge = true; count = folio_free_raw_hwp(folio, false); if (count == 0) { - ret = -EBUSY; folio_put(folio); goto unlock_mutex; }