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 B7F59185B68 for ; Wed, 6 Nov 2024 01:00:00 +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=1730854800; cv=none; b=m80crCmROlv6I0T5FZYIq6GQFmku08jVFnmvRlaMK2WbWG3Ha5xteFnm2fnEBuKazAZQ/YX2r/PkI4Jg5doxUkh8Dp5JkNYle53iOYGZ+hZ4bvF3cjy386H42Q22AoN7f540QBcfstUte2lBiMTomRjTIQ8ChSO3uBivMWKgeJA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730854800; c=relaxed/simple; bh=pwKMxCxoS676IYYUzfZ11p43S68Rp7fPzsC7kAqjgL8=; h=Date:To:From:Subject:Message-Id; b=lu8haQ9VdyopkaOTWjpHPAh2SuI9Yf/N579rvbZUkgHj80K2ui9kLrYkJ8TX6mOiRJLJjJ5zEWlmA4CA36QtIDfrEXLbSvy0SOZi5ZBDBE3v0BQzh583Q5w4vwDeTPKS0xjzJhFLc10SyT9RITncmLc2O3J5iznNICOt8NzqcXs= 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=FYzYY2Nf; 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="FYzYY2Nf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B8CBC4CECF; Wed, 6 Nov 2024 01:00:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1730854800; bh=pwKMxCxoS676IYYUzfZ11p43S68Rp7fPzsC7kAqjgL8=; h=Date:To:From:Subject:From; b=FYzYY2NfTPNKMxSWC92nyG7Tc5/HM/lxbkKPbSLm9R2oMtgljmNCZRajNG/ZE7yCL Ag+IpYiwkCiB3zoaHPXd0/6PU7wa2rBeaPwEXNNTenNaeTzKVqArDN4RUJB1UJaQwg CGYHWST/nhDVeme9k96YI3VVFO2vorHtagtr/oqU= Date: Tue, 05 Nov 2024 17:00:00 -0800 To: mm-commits@vger.kernel.org,ying.huang@intel.com,willy@infradead.org,wangkefeng.wang@huawei.com,vbabka@suse.cz,ryan.roberts@arm.com,linmiaohe@huawei.com,keescook@chromium.org,jhubbard@nvidia.com,glider@google.com,david@redhat.com,ziy@nvidia.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-avoid-zeroing-user-movable-page-twice-with-init_on_alloc=1.patch removed from -mm tree Message-Id: <20241106010000.8B8CBC4CECF@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm: avoid zeroing user movable page twice with init_on_alloc=1 has been removed from the -mm tree. Its filename was mm-avoid-zeroing-user-movable-page-twice-with-init_on_alloc=1.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: Zi Yan Subject: mm: avoid zeroing user movable page twice with init_on_alloc=1 Date: Fri, 11 Oct 2024 11:03:04 -0400 Commit 6471384af2a6 ("mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options") forces allocated page to be zeroed in post_alloc_hook() when init_on_alloc=1. For order-0 folios, if arch does not define vma_alloc_zeroed_movable_folio(), the default implementation again zeros the page return from the buddy allocator. So the page is zeroed twice. Fix it by passing __GFP_ZERO instead to avoid double page zeroing. At the moment, s390,arm64,x86,alpha,m68k are not impacted since they define their own vma_alloc_zeroed_movable_folio(). For >0 order folios (mTHP and PMD THP), folio_zero_user() is called to zero the folio again. Fix it by calling folio_zero_user() only if init_on_alloc is set. All arch are impacted. Add alloc_zeroed() helper to encapsulate the init_on_alloc check. [ziy@nvidia.com: comment fixes, per David] Link: https://lkml.kernel.org/r/97DB52E1-C594-49B5-9736-89AC302FAB01@nvidia.com Link: https://lkml.kernel.org/r/20241011150304.709590-1-ziy@nvidia.com Signed-off-by: Zi Yan Acked-by: Vlastimil Babka Acked-by: David Hildenbrand Cc: Alexander Potapenko Cc: "Huang, Ying" Cc: John Hubbard Cc: Kees Cook Cc: Kefeng Wang Cc: Matthew Wilcox Cc: Miaohe Lin Cc: Ryan Roberts Signed-off-by: Andrew Morton --- include/linux/highmem.h | 8 +------- mm/huge_memory.c | 8 +++++++- mm/internal.h | 6 ++++++ mm/memory.c | 10 +++++++++- 4 files changed, 23 insertions(+), 9 deletions(-) --- a/include/linux/highmem.h~mm-avoid-zeroing-user-movable-page-twice-with-init_on_alloc=1 +++ a/include/linux/highmem.h @@ -224,13 +224,7 @@ static inline struct folio *vma_alloc_zeroed_movable_folio(struct vm_area_struct *vma, unsigned long vaddr) { - struct folio *folio; - - folio = vma_alloc_folio(GFP_HIGHUSER_MOVABLE, 0, vma, vaddr); - if (folio) - clear_user_highpage(&folio->page, vaddr); - - return folio; + return vma_alloc_folio(GFP_HIGHUSER_MOVABLE | __GFP_ZERO, 0, vma, vaddr); } #endif --- a/mm/huge_memory.c~mm-avoid-zeroing-user-movable-page-twice-with-init_on_alloc=1 +++ a/mm/huge_memory.c @@ -1165,7 +1165,13 @@ static struct folio *vma_alloc_anon_foli } folio_throttle_swaprate(folio, gfp); - folio_zero_user(folio, addr); + /* + * When a folio is not zeroed during allocation (__GFP_ZERO not used), + * folio_zero_user() is used to make sure that the page corresponding + * to the faulting address will be hot in the cache after zeroing. + */ + if (!alloc_zeroed()) + folio_zero_user(folio, addr); /* * The memory barrier inside __folio_mark_uptodate makes sure that * folio_zero_user writes become visible before the set_pmd_at() --- a/mm/internal.h~mm-avoid-zeroing-user-movable-page-twice-with-init_on_alloc=1 +++ a/mm/internal.h @@ -1276,6 +1276,12 @@ void touch_pud(struct vm_area_struct *vm void touch_pmd(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd, bool write); +static inline bool alloc_zeroed(void) +{ + return static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, + &init_on_alloc); +} + enum { /* mark page accessed */ FOLL_TOUCH = 1 << 16, --- a/mm/memory.c~mm-avoid-zeroing-user-movable-page-twice-with-init_on_alloc=1 +++ a/mm/memory.c @@ -4719,7 +4719,15 @@ static struct folio *alloc_anon_folio(st goto next; } folio_throttle_swaprate(folio, gfp); - folio_zero_user(folio, vmf->address); + /* + * When a folio is not zeroed during allocation + * (__GFP_ZERO not used), folio_zero_user() is used + * to make sure that the page corresponding to the + * faulting address will be hot in the cache after + * zeroing. + */ + if (!alloc_zeroed()) + folio_zero_user(folio, vmf->address); return folio; } next: _ Patches currently in -mm which might be from ziy@nvidia.com are