From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2187038DD3 for ; Tue, 9 Sep 2025 00:09:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757376592; cv=none; b=d9tNC6Z7iGQO+jq8P4KfUmS8uRdan+tnCLJBkp3Ldy7dNYFrzQcVZrTOxb/Dq1qU+IUf/71rfZpOfipd+oNphBDUo4OemmEp21xOgxi8+IgR5/52P53maluCASN7SOR08RUnKdQiNggREzMH+M1bcDLFV6vwAr0fg38bkqZ1zBY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757376592; c=relaxed/simple; bh=gF0Ef0b6fujrVveaR6B/RYG1ikDUrfw6dE6+dUQthKQ=; h=Date:To:From:Subject:Message-Id; b=FiD9wE2m+OW15WVcNPuI/QAUlaOsVysVJclZJ75hqO6HEFFEaiqoSWfL2mK0q3GAsMpik49lPAkP6li+XOwLcL91o4OU3hACPFy+m+kJMauwIEMRCEIqxK+XAC6LpkPIdoXMwH/jTMGopuz2km3wTH6vqlzP+WT3QYQ9zMdM91I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=jsvZmwTP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="jsvZmwTP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA564C4CEF1; Tue, 9 Sep 2025 00:09:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1757376592; bh=gF0Ef0b6fujrVveaR6B/RYG1ikDUrfw6dE6+dUQthKQ=; h=Date:To:From:Subject:From; b=jsvZmwTP+KcHdkxCYvera0ZBLPt+9FkcGJLNyuJ26hRmEtJN7+Dk36b2NusquOwjK Bfc+SWUOEXjk3eAImcyI3287luQxOiEIkmdsFD5yC6MeIS1kE0+kZq//krKxz/oDfv PBbglhIn2FnXjtd5ZiKCyLkpKYbJQaOsiz2GwPWg= Date: Mon, 08 Sep 2025 17:09:51 -0700 To: mm-commits@vger.kernel.org,peterx@redhat.com,jhubbard@nvidia.com,jgg@ziepe.ca,imbrenda@linux.ibm.com,borntraeger@de.ibm.com,david@redhat.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-gup-fix-handling-of-errors-from-arch_make_folio_accessible-in-follow_page_pte.patch added to mm-new branch Message-Id: <20250909000951.DA564C4CEF1@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/gup: fix handling of errors from arch_make_folio_accessible() in follow_page_pte() has been added to the -mm mm-new branch. Its filename is mm-gup-fix-handling-of-errors-from-arch_make_folio_accessible-in-follow_page_pte.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-gup-fix-handling-of-errors-from-arch_make_folio_accessible-in-follow_page_pte.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. 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: David Hildenbrand Subject: mm/gup: fix handling of errors from arch_make_folio_accessible() in follow_page_pte() Date: Mon, 8 Sep 2025 11:45:17 +0200 In case we call arch_make_folio_accessible() and it fails, we would incorrectly return a value that is "!= 0" to the caller, indicating that we pinned all requested pages and that the caller can keep going. follow_page_pte() is not supposed to return error values, but instead "0" on failure and "1" on success -- we'll clean that up separately. In case we return "!= 0", the caller will just keep going pinning more pages. If we happen to pin a page afterwards, we're in trouble, because we essentially skipped some pages in the requested range. Staring at the arch_make_folio_accessible() implementation on s390x, I assume it should actually never really fail unless something unexpected happens (BUG?). So let's not CC stable and just fix common code to do the right thing. Clean up the code a bit now that there is no reason to store the return value of arch_make_folio_accessible(). Link: https://lkml.kernel.org/r/20250908094517.303409-1-david@redhat.com Fixes: f28d43636d6f ("mm/gup/writeback: add callbacks for inaccessible pages") Signed-off-by: David Hildenbrand Cc: Claudio Imbrenda Cc: Jason Gunthorpe Cc: John Hubbard Cc: Peter Xu Cc: Christian Borntraeger Signed-off-by: Andrew Morton --- mm/gup.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) --- a/mm/gup.c~mm-gup-fix-handling-of-errors-from-arch_make_folio_accessible-in-follow_page_pte +++ a/mm/gup.c @@ -2898,12 +2898,9 @@ static int gup_fast_pte_range(pmd_t pmd, * see Documentation/core-api/pin_user_pages.rst for * details. */ - if (flags & FOLL_PIN) { - ret = arch_make_folio_accessible(folio); - if (ret) { - gup_put_folio(folio, 1, flags); - goto pte_unmap; - } + if ((flags & FOLL_PIN) && arch_make_folio_accessible(folio)) { + gup_put_folio(folio, 1, flags); + goto pte_unmap; } folio_set_referenced(folio); pages[*nr] = page; _ Patches currently in -mm which might be from david@redhat.com are mm-migrate-remove-migratepage_unmap.patch mm-migrate-remove-migratepage_unmap-fix.patch treewide-remove-migratepage_success.patch mm-huge_memory-move-more-common-code-into-insert_pmd.patch mm-huge_memory-move-more-common-code-into-insert_pud.patch mm-huge_memory-support-huge-zero-folio-in-vmf_insert_folio_pmd.patch fs-dax-use-vmf_insert_folio_pmd-to-insert-the-huge-zero-folio.patch mm-huge_memory-mark-pmd-mappings-of-the-huge-zero-folio-special.patch powerpc-ptdump-rename-struct-pgtable_level-to-struct-ptdump_pglevel.patch mm-rmap-convert-enum-rmap_level-to-enum-pgtable_level.patch mm-memory-convert-print_bad_pte-to-print_bad_page_map.patch mm-memory-convert-print_bad_pte-to-print_bad_page_map-fix.patch mm-memory-factor-out-common-code-from-vm_normal_page_.patch mm-introduce-and-use-vm_normal_page_pud.patch mm-rename-vm_ops-find_special_page-to-vm_ops-find_normal_page.patch prctl-extend-pr_set_thp_disable-to-optionally-exclude-vm_hugepage.patch mm-huge_memory-convert-tva_flags-to-enum-tva_type.patch mm-huge_memory-respect-madv_collapse-with-pr_thp_disable_except_advised.patch mm-stop-making-sparsemem_vmemmap-user-selectable.patch arm64-kconfig-drop-superfluous-select-sparsemem_vmemmap.patch s390-kconfig-drop-superfluous-select-sparsemem_vmemmap.patch x86-kconfig-drop-superfluous-select-sparsemem_vmemmap.patch wireguard-selftests-remove-config_sparsemem_vmemmap=y-from-qemu-kernel-config.patch mm-page_alloc-reject-unreasonable-folio-compound-page-sizes-in-alloc_contig_range_noprof.patch mm-memremap-reject-unreasonable-folio-compound-page-sizes-in-memremap_pages.patch mm-hugetlb-check-for-unreasonable-folio-sizes-when-registering-hstate.patch mm-mm_init-make-memmap_init_compound-look-more-like-prep_compound_page.patch mm-sanity-check-maximum-folio-size-in-folio_set_order.patch mm-limit-folio-compound-page-sizes-in-problematic-kernel-configs.patch mm-simplify-folio_page-and-folio_page_idx.patch mm-hugetlb-cleanup-hugetlb_folio_init_tail_vmemmap.patch mm-mm-percpu-km-drop-nth_page-usage-within-single-allocation.patch fs-hugetlbfs-remove-nth_page-usage-within-folio-in-adjust_range_hwpoison.patch fs-hugetlbfs-cleanup-folio-in-adjust_range_hwpoison.patch mm-pagewalk-drop-nth_page-usage-within-folio-in-folio_walk_start.patch mm-gup-drop-nth_page-usage-within-folio-when-recording-subpages.patch mm-gup-remove-record_subpages.patch mm-gup-remove-record_subpages-fix.patch io_uring-zcrx-remove-nth_page-usage-within-folio.patch mips-mm-convert-__flush_dcache_pages-to-__flush_dcache_folio_pages.patch mm-cma-refuse-handing-out-non-contiguous-page-ranges.patch dma-remap-drop-nth_page-in-dma_common_contiguous_remap.patch scatterlist-disallow-non-contigous-page-ranges-in-a-single-sg-entry.patch ata-libata-sff-drop-nth_page-usage-within-sg-entry.patch drm-i915-gem-drop-nth_page-usage-within-sg-entry.patch mspro_block-drop-nth_page-usage-within-sg-entry.patch memstick-drop-nth_page-usage-within-sg-entry.patch mmc-drop-nth_page-usage-within-sg-entry.patch scsi-scsi_lib-drop-nth_page-usage-within-sg-entry.patch scsi-sg-drop-nth_page-usage-within-sg-entry.patch vfio-pci-drop-nth_page-usage-within-sg-entry.patch crypto-remove-nth_page-usage-within-sg-entry.patch mm-gup-drop-nth_page-usage-in-unpin_user_page_range_dirty_lock.patch kfence-drop-nth_page-usage.patch block-update-comment-of-struct-bio_vec-regarding-nth_page.patch mm-remove-nth_page.patch selftests-mm-split_huge_page_test-fix-occasional-is_backed_by_folio-wrong-results.patch selftests-mm-split_huge_page_test-cleanups-for-split_pte_mapped_thp-test.patch mm-gup-fix-handling-of-errors-from-arch_make_folio_accessible-in-follow_page_pte.patch