From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2D87BCA100C for ; Wed, 3 Sep 2025 07:03:04 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8C89E8E0009; Wed, 3 Sep 2025 03:03:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 89FF96B000C; Wed, 3 Sep 2025 03:03:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7430D8E0009; Wed, 3 Sep 2025 03:03:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 5AAF06B0008 for ; Wed, 3 Sep 2025 03:03:03 -0400 (EDT) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 2853A13B04C for ; Wed, 3 Sep 2025 07:03:03 +0000 (UTC) X-FDA: 83847047046.25.B32B5B6 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf17.hostedemail.com (Postfix) with ESMTP id E39D440010 for ; Wed, 3 Sep 2025 07:03:00 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Qkmel6dh; spf=pass (imf17.hostedemail.com: domain of dhildenb@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=dhildenb@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1756882980; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=9yhEzid0coX4qzN/T+DJZ37q8NluTxlwBeVgR6BscUg=; b=t7VgbPbeo1gmUCX56N8/TTk1CeoGxo8AJIZV9c7sTc4iSmDSl+LLwr5nYLJcFzjRsIvJKk yTSGBfmmSjmlYaBC/4AIUo7psH3MayxU3F3G2rGhpCnvmzU25oUyiNXSVFiyh8StotlRqE 4fImnXxCoDLrkpBZL2I2kzg1c6t7X28= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Qkmel6dh; spf=pass (imf17.hostedemail.com: domain of dhildenb@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=dhildenb@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1756882981; a=rsa-sha256; cv=none; b=UkNedqQwNXCPiOEFpXsje5c1bDygFqEw6UsTvLlGbU0sU5LgUhRfM+t/4wjj67hDakiBem Zh/jANu9gIv3rI2K3dXmphce9VoRWl901OX47ou6w9FN0r8WRRRz6YtSzkTtFP4gFADz0+ diS5c6QLhAVxwJwR8aLKRssxUZ8xhgo= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1756882980; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9yhEzid0coX4qzN/T+DJZ37q8NluTxlwBeVgR6BscUg=; b=Qkmel6dhW9n9jCjIN8ijRbctAO4ROTsrpdAy4+vyohGQOAP2hTLdvRrkOlB1AgefUk+byp SWSBbAZRONmv5/EztzcUbQ/syI18C2a/kbE7bZq2ougWZRa7nHqt7WI1s1R6Z3HsErd6Qm j+twMBlqWjBYY0n28jz2yYbGbq/dm9Q= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-391-n8beVVAYMFWH1sBhxPHKpw-1; Wed, 03 Sep 2025 03:02:59 -0400 X-MC-Unique: n8beVVAYMFWH1sBhxPHKpw-1 X-Mimecast-MFC-AGG-ID: n8beVVAYMFWH1sBhxPHKpw_1756882978 Received: by mail-wr1-f69.google.com with SMTP id ffacd0b85a97d-3d1fe9ecd9dso2943266f8f.0 for ; Wed, 03 Sep 2025 00:02:58 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1756882978; x=1757487778; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=9yhEzid0coX4qzN/T+DJZ37q8NluTxlwBeVgR6BscUg=; b=e0JJW+rSfxS2udp5x7I2t0CtQRij7HXB9EEHxptPeL4ppmDIHMCe4WMvcjuJeWOyjE 0Mgtcjx4z9YYtCAq1MmZ25QiSrcMJ9ZuJ6ACiN/A1yfjFFQyioLTU+fQiSg9t8fkdSs2 ReSEuHdLpF8qORWsWm0iNIZKYdmNXEeTfjCqjO/tWioXmRuS8qB3wvurFHPgRWncR+ZB bPXRBIeoXe57CGYqUOqAXkIBjEl3ttgfpxtuNi446t1GKDVOgV++g7q2tR+GHkePIBvh 9DUZx8ElOve2sAlGAMr+GW9y/IVpCuR/MnbCi28JnbEwwVCkEpa4micb02tDwSUTQ8hs Bf/Q== X-Gm-Message-State: AOJu0Yzee1KclUKY8y6F2DVx1xBwnUBIEbuh1z9XcoeYuDPBmP/s/8Ik 5etsFwYQaa65jRRfHh13fx9EMW79XG4tCD+383aFk0XHOtCGCA2lGgrr0xwG9oVkC0wQvQI15dp piolxzT0GVEkSu1J/O1+Bt7e7z77kDQPzOUIAn1lIQIk7cv0cm5wK X-Gm-Gg: ASbGnct1jOaMt+toboLr+EWnUBQcOLbCUMbHYUpROKKXk8LNTkaraBlukshQeAoGA69 i8EN0xqDpGDemlL38GK9rY8tnjiQabnS7QZKnRp0FrPoO2sxGtZEP9c85In3BCvjdj8kwDPWRBx hnoj115yibRhqlGIK3fZrbZ2GcC5vVXzuIS5yvFro6YSIS+LUlfzWcwpbya1HWxX50Yaho9XgBJ P51JJl9AbEnQ5DWe/HaH5upQWDpZzwzRypu5ER2QtoJXvfeP13cviVXOyFDl2jJnVwNyPXf29+7 gCCWCnhHYkh8TprptVuTtCQUKpXllAIi6xmG5npqBLgHOU6doSFz6Vowl2QkL1GUb+QgwZ4/FP9 s/KoRvR1Gsn0PZrJZSyj0O9a0 X-Received: by 2002:a05:6000:290f:b0:3c9:ad8:fec9 with SMTP id ffacd0b85a97d-3d1df539f94mr10808514f8f.58.1756882977768; Wed, 03 Sep 2025 00:02:57 -0700 (PDT) X-Google-Smtp-Source: AGHT+IF6G9T+n01gQot9IX0ds2bfSowvj6oYMtabhkeOUIoI2hiuiSDp08eAIEryVuwexq/s1b1Xkw== X-Received: by 2002:a05:6000:290f:b0:3c9:ad8:fec9 with SMTP id ffacd0b85a97d-3d1df539f94mr10808480f8f.58.1756882977316; Wed, 03 Sep 2025 00:02:57 -0700 (PDT) Received: from localhost (p200300d82f099c0081732a94640ddd31.dip0.t-ipconnect.de. [2003:d8:2f09:9c00:8173:2a94:640d:dd31]) by smtp.gmail.com with UTF8SMTPSA id 5b1f17b1804b1-45b6f0c6dc1sm309420145e9.1.2025.09.03.00.02.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 03 Sep 2025 00:02:56 -0700 (PDT) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org, David Hildenbrand , Andrew Morton , Lorenzo Stoakes , Zi Yan , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Wei Yang Subject: [PATCH v2 1/2] selftests/mm: split_huge_page_test: fix occasional is_backed_by_folio() wrong results Date: Wed, 3 Sep 2025 09:02:52 +0200 Message-ID: <20250903070253.34556-2-david@redhat.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250903070253.34556-1-david@redhat.com> References: <20250903070253.34556-1-david@redhat.com> MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: 4nPS_bLnD2v8TcX8bKX69pd_82Knnz4JrqC-GIJcC88_1756882978 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit content-type: text/plain; charset="US-ASCII"; x-default=true X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: E39D440010 X-Stat-Signature: ugz5yitp1pexmpstbrb9t4c1zeeyhqah X-Rspam-User: X-HE-Tag: 1756882980-3472 X-HE-Meta: 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 B8GIBydE 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: When checking for actual tail or head pages of a folio, we must make sure that the KPF_COMPOUND_HEAD/KPF_COMPOUND_TAIL flag is paired with KPF_THP. For example, if we have another large folio after our large folio in physical memory, our "pfn_flags & (KPF_THP | KPF_COMPOUND_TAIL)" would trigger even though it's actually a head page of the next folio. If is_backed_by_folio() returns a wrong result, split_pte_mapped_thp() can fail with "Some THPs are missing during mremap". Fix it by checking for head/tail pages of folios properly. Add folio_tail_flags/folio_head_flags to improve readability and use these masks also when just testing for any compound page. Fixes: 169b456b0162 ("selftests/mm: reimplement is_backed_by_thp() with more precise check") Reviewed-by: Zi Yan Reviewed-by: Wei Yang Signed-off-by: David Hildenbrand --- tools/testing/selftests/mm/split_huge_page_test.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c index 10ae65ea032f6..72d6d8bb329ed 100644 --- a/tools/testing/selftests/mm/split_huge_page_test.c +++ b/tools/testing/selftests/mm/split_huge_page_test.c @@ -44,6 +44,8 @@ int kpageflags_fd; static bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd, int kpageflags_fd) { + const uint64_t folio_head_flags = KPF_THP | KPF_COMPOUND_HEAD; + const uint64_t folio_tail_flags = KPF_THP | KPF_COMPOUND_TAIL; const unsigned long nr_pages = 1UL << order; unsigned long pfn_head; uint64_t pfn_flags; @@ -61,7 +63,7 @@ static bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd, /* check for order-0 pages */ if (!order) { - if (pfn_flags & (KPF_THP | KPF_COMPOUND_HEAD | KPF_COMPOUND_TAIL)) + if (pfn_flags & (folio_head_flags | folio_tail_flags)) return false; return true; } @@ -76,14 +78,14 @@ static bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd, goto fail; /* head PFN has no compound_head flag set */ - if (!(pfn_flags & (KPF_THP | KPF_COMPOUND_HEAD))) + if ((pfn_flags & folio_head_flags) != folio_head_flags) return false; /* check all tail PFN flags */ for (i = 1; i < nr_pages; i++) { if (pageflags_get(pfn_head + i, kpageflags_fd, &pfn_flags)) goto fail; - if (!(pfn_flags & (KPF_THP | KPF_COMPOUND_TAIL))) + if ((pfn_flags & folio_tail_flags) != folio_tail_flags) return false; } @@ -94,11 +96,8 @@ static bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd, if (pageflags_get(pfn_head + nr_pages, kpageflags_fd, &pfn_flags)) return true; - /* this folio is bigger than the given order */ - if (pfn_flags & (KPF_THP | KPF_COMPOUND_TAIL)) - return false; - - return true; + /* If we find another tail page, then the folio is larger. */ + return (pfn_flags & folio_tail_flags) != folio_tail_flags; fail: ksft_exit_fail_msg("Failed to get folio info\n"); return false; -- 2.50.1