From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 01C813921FB; Wed, 29 Jul 2026 04:14:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785298455; cv=none; b=hHcR48KQR9VqeB8s8PxKU4pRRg4sGAPuVvmgJ3pZCX7AEFgMU1o0Hsn/m+n6vyk+vYkoGeK2GKF393NEtEhlWuVtcvBifkhGhYtPrebrcCnN1Ski/+S/e+LvNQQPAAy48Bh0aCLCnNhxhQyEJuBj9BmJqN7xFE+SwhzDHCBIqlI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785298455; c=relaxed/simple; bh=uAqWwSx1krd09YW9OEywXNUh2OLYaOBuiyAUiQJvrGk=; h=Date:To:From:Subject:Message-Id; b=nyXH5000tXeKvlry8LeRR4vfJmQgCJWt16p5lCxZm0GbiLf2zysQIxbHfMgN89NOi8+FL6tcrwB/UGGHFIvmMriws0JM2YSZA09u6hTmtAM6xnGPVRPspgYrYHWKWGwzb+iSqPz15Ub1ktmQ/7hGxkklo3BKagIVxaVMXKgeFFI= 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=F2DgNgW1; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="F2DgNgW1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D2CF21F000E9; Wed, 29 Jul 2026 04:14:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1785298453; bh=89m40eLBioELf2OBipEcGjmcu1T409SGH9GwmoX+ioQ=; h=Date:To:From:Subject; b=F2DgNgW1tTdQ21a8Eb0jar8gaFsueALWxgVy28nJNH3U1+SiGNHmOpgA392TQXphU HcyW7UcVE/dMiOc5C741jphYaXJZ6CwvEt9LdIdjOZZ87k5397ZpD2r6VTnYeQVxVw tgHnnISIE++jWJSmgpVsRZ7eO3wD5di/w6BjWSjM= Date: Tue, 28 Jul 2026 21:14:13 -0700 To: mm-commits@vger.kernel.org,vbabka@kernel.org,usama.arif@linux.dev,stable@vger.kernel.org,rppt@kernel.org,ritesh.list@gmail.com,osalvador@suse.de,osalvador@kernel.org,npiggin@gmail.com,mpe@ellerman.id.au,mclapinski@google.com,maddy@linux.ibm.com,ljs@kernel.org,liam@infradead.org,fvdl@google.com,david@kernel.org,aneesh.kumar@linux.ibm.com,songmuchun@bytedance.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-hugetlb-fix-boot-panic-with-config_debug_vm-and-hvo-bootmem-pages.patch removed from -mm tree Message-Id: <20260729041413.D2CF21F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/hugetlb: fix boot panic with CONFIG_DEBUG_VM and HVO bootmem pages has been removed from the -mm tree. Its filename was mm-hugetlb-fix-boot-panic-with-config_debug_vm-and-hvo-bootmem-pages.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Muchun Song Subject: mm/hugetlb: fix boot panic with CONFIG_DEBUG_VM and HVO bootmem pages Date: Fri, 12 Jun 2026 11:58:45 +0800 Patch series "mm: Refactor bootmem gigantic hugepage allocation", v4. This series is split out from the earlier larger series "mm: Generalize HVO for HugeTLB and device DAX" [1]. It collects the first 19 patches of that series as a standalone set of fixes and preparatory cleanups around bootmem HugeTLB handling, sparse initialization ordering, and related vmemmap setup. The first patches fix a few bugs found while reviewing the existing code, including incorrect bootmem HVO handling, wrong vmemmap registration arguments, a powerpc compound-vmemmap tracking bug, and too-late initialization of gigantic bootmem HugeTLB struct pages. The rest of the series reorders early memory initialization so the relevant zone state is available before sparse and HugeTLB boot-time setup runs, then simplifies the remaining bootmem gigantic hugepage allocation path and removes code made obsolete by that rework. At a high level: - patches [1-4] fix boot-time and arch-specific bugs - patches [5-12] reorder and simplify sparse/mm/hugetlb early init - patches [13-19] refactor bootmem gigantic hugepage allocation and remove obsolete helpers and state This patch (of 19): Commit 622026e87c40 ("mm/hugetlb: remove fake head pages") switched HVO to reuse per-zone shared tail pages from zone->vmemmap_tails[]. Those shared tail pages were initialized in hugetlb_vmemmap_init(), but bootmem HugeTLB folios are prepared earlier from gather_bootmem_prealloc(). With hugetlb_free_vmemmap=on, prep_and_add_bootmem_folios() can access pageblock flags on bootmem HugeTLB pages whose mirrored tail struct pages already point to the shared tail page. On CONFIG_DEBUG_VM kernels, get_pfnblock_bitmap_bitidx() then dereferences the still-uninitialized shared tail page and can panic during boot. Initialize zone->vmemmap_tails[] from gather_bootmem_prealloc(), before bootmem HugeTLB folios are processed, and drop the later initialization from hugetlb_vmemmap_init(). This bug only affects CONFIG_DEBUG_VM kernels, where the relevant assertion is evaluated. Link: https://lore.kernel.org/20260612035903.2468601-1-songmuchun@bytedance.com Link: https://lore.kernel.org/20260612035903.2468601-2-songmuchun@bytedance.com Fixes: 622026e87c40 ("mm/hugetlb: remove fake head pages") Signed-off-by: Muchun Song Acked-by: Oscar Salvador Tested-by: Michal Clapinski Reviewed-by: Michal Clapinski Cc: "Aneesh Kumar K.V" Cc: David Hildenbrand Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Mike Rapoport Cc: Nicholas Piggin Cc: "Ritesh Harjani (IBM)" Cc: Vlastimil Babka Cc: Frank van der Linden Cc: Oscar Salvador (SUSE) Cc: Usama Arif Cc: Signed-off-by: Andrew Morton --- mm/hugetlb.c | 25 +++++++++++++++++++++++++ mm/hugetlb_vmemmap.c | 17 ----------------- mm/sparse-vmemmap.c | 2 +- 3 files changed, 26 insertions(+), 18 deletions(-) --- a/mm/hugetlb.c~mm-hugetlb-fix-boot-panic-with-config_debug_vm-and-hvo-bootmem-pages +++ a/mm/hugetlb.c @@ -3365,6 +3365,31 @@ static void __init gather_bootmem_preall .max_threads = num_node_state(N_MEMORY), .numa_aware = true, }; +#ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP + struct zone *zone; + + for_each_zone(zone) { + for (int i = 0; i < NR_VMEMMAP_TAILS; i++) { + struct page *tail, *p; + unsigned int order; + + tail = zone->vmemmap_tails[i]; + if (!tail) + continue; + + order = i + VMEMMAP_TAIL_MIN_ORDER; + p = page_to_virt(tail); + /* + * prep_and_add_bootmem_folios() can access pageblock + * flags on bootmem HugeTLB pages, so initialize the + * shared tail struct pages here before bootmem folios + * start using them. + */ + for (int j = 0; j < PAGE_SIZE / sizeof(struct page); j++) + init_compound_tail(p + j, NULL, order, zone); + } + } +#endif padata_do_multithreaded(&job); } --- a/mm/hugetlb_vmemmap.c~mm-hugetlb-fix-boot-panic-with-config_debug_vm-and-hvo-bootmem-pages +++ a/mm/hugetlb_vmemmap.c @@ -870,27 +870,10 @@ static const struct ctl_table hugetlb_vm static int __init hugetlb_vmemmap_init(void) { const struct hstate *h; - struct zone *zone; /* HUGETLB_VMEMMAP_RESERVE_SIZE should cover all used struct pages */ BUILD_BUG_ON(__NR_USED_SUBPAGE > HUGETLB_VMEMMAP_RESERVE_PAGES); - for_each_zone(zone) { - for (int i = 0; i < NR_VMEMMAP_TAILS; i++) { - struct page *tail, *p; - unsigned int order; - - tail = zone->vmemmap_tails[i]; - if (!tail) - continue; - - order = i + VMEMMAP_TAIL_MIN_ORDER; - p = page_to_virt(tail); - for (int j = 0; j < PAGE_SIZE / sizeof(struct page); j++) - init_compound_tail(p + j, NULL, order, zone); - } - } - for_each_hstate(h) { if (hugetlb_vmemmap_optimizable(h)) { register_sysctl_init("vm", hugetlb_vmemmap_sysctls); --- a/mm/sparse-vmemmap.c~mm-hugetlb-fix-boot-panic-with-config_debug_vm-and-hvo-bootmem-pages +++ a/mm/sparse-vmemmap.c @@ -342,7 +342,7 @@ static __meminit struct page *vmemmap_ge * * Any initialization done here will be overwritten by memmap_init(). * - * hugetlb_vmemmap_init() will take care of initialization after + * gather_bootmem_prealloc() will take care of initialization after * memmap_init(). */ _ Patches currently in -mm which might be from songmuchun@bytedance.com are selftests-mm-remove-obsolete-hugetlb-vmemmap-test.patch