From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793214383; b=K8qVb3DekIstJbkvm3chrnwWf7O9DmYm90eucDywCDvmpMwp9VvBGpUFrhOOgM+3ZN2l wqWB9T089XKVqNkHtwBZNJAQVxV0aa1cQ+sOir45YOV6VuR0bfN6rPoY3zuYW/bPS4R12 ZXkdgQu0fIaesFPqZSY86m7TGs8SeW4rE+Io3PKOYBeBz6zXo62tH4opNGlZ5GBaEOULs Muv/qJeNhK4B8tYnD2vrWZUO2MP//RRwungBP3RKXfSRDH1jkIEFAjA3skVFSIZadTRvw dXttKpFaDzlC82bKjo6eQq5IV045+lWpmFLbMPEa/Gd5B3neWc079iAOeld8iXPVt6A== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793214383; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=HCOazxDGeOTNkGpAX9w3vECCzj/VoJ2H6j8kyMFnUbo=; b=oCmeM4dZlwwbf7/i+GChg9wOtK4rUCHwcp8hmXsmHyY2PWhPf4pF0wckVJC+BfG9Hpll v/G+DKU2gyxbOI3eQ9G63EPQ5Y0RBgnP0SiRvmyjwGaqIk47160wqm2OYaSZJgeAaFIF0 2OIxTi277wqPvyByEUJnluDNBWJ9BKA/QMNFoeKCss5uCBpZjRsGuryG7+RclPVibBMfr DmSRhHhcq6ptGv7ZJKpCZUii7+pKE66Z/KGMhSi4OabT4Y5jMM9cYHS4EGeg7505OeIdE aMgFCMaNU9BoPztO5caFK300R+GCrf+7mbXqUge2tPPY5NiZlXSSBm+kqEjBGI1aBPw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=Y8yAOVIL; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A5C04606A33D; Wed, 28 Oct 2026 19:06:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=Y8yAOVIL Received: by smtp.kernel.org (Postfix) with ESMTPSA id D438F1F01828; Wed, 28 Oct 2026 19:06:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793214382; bh=HCOazxDGeOTNkGpAX9w3vECCzj/VoJ2H6j8kyMFnUbo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Y8yAOVILiOar87QnbmXM0/HhHPm7rKoTHsgPhZRvC9FL58aA5DmugieDqAXKrTV38 /60oVQxd4NnxpJ5nmtg1T11qV7zK5s3kqqH0hs4HGcB2zPBCYlrP3wO8MLNCaNzXH2 gxMVFvigd/p/jhA/GN0JDuRMX0y8/fcVJNf5/Xik= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jinjiang Tu , David Hildenbrand , Andrei Vagin , Andrii Nakryiko , Baolin Wang , Brahmajit Das , Catalin Marinas , Christophe Leroy , David Rientjes , Dev Jain , Hugh Dickins , Joern Engel , Kefeng Wang , Lorenzo Stoakes , Michal Hocko , Ryan Roberts , Thiago Jung Bauermann , Andrew Morton , Sasha Levin Subject: [PATCH 6.1 0838/1887] mm/smaps: fix race between smaps_hugetlb_range and migration Date: Wed, 28 Oct 2026 17:48:54 +0100 Message-ID: <20261028170518.496932996@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170459.200466217@linuxfoundation.org> References: <20261028170459.200466217@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jinjiang Tu [ Upstream commit 45d19b4b6c2d422771c29b83462d84afcbb33f01 ] smaps_hugetlb_range() handles the pte without holdling ptl, and may be concurrenct with migration, leaing to BUG_ON in pfn_swap_entry_to_page(). The race is as follows. smaps_hugetlb_range migrate_pages huge_ptep_get remove_migration_ptes folio_unlock pfn_swap_entry_folio BUG_ON To fix it, hold ptl lock in smaps_hugetlb_range(). Link: https://lkml.kernel.org/r/20250724090958.455887-1-tujinjiang@huawei.com Link: https://lkml.kernel.org/r/20250724090958.455887-2-tujinjiang@huawei.com Fixes: 25ee01a2fca0 ("mm: hugetlb: proc: add hugetlb-related fields to /proc/PID/smaps") Signed-off-by: Jinjiang Tu Acked-by: David Hildenbrand Cc: Andrei Vagin Cc: Andrii Nakryiko Cc: Baolin Wang Cc: Brahmajit Das Cc: Catalin Marinas Cc: Christophe Leroy Cc: David Rientjes Cc: Dev Jain Cc: Hugh Dickins Cc: Joern Engel Cc: Kefeng Wang Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Ryan Roberts Cc: Thiago Jung Bauermann Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- fs/proc/task_mmu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index 484886cdd272c..eb002adf9f59f 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -727,7 +727,9 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask, struct mem_size_stats *mss = walk->private; struct vm_area_struct *vma = walk->vma; struct page *page = NULL; + spinlock_t *ptl; + ptl = huge_pte_lock(hstate_vma(vma), walk->mm, pte); if (pte_present(*pte)) { page = vm_normal_page(vma, addr, *pte); } else if (is_swap_pte(*pte)) { @@ -742,6 +744,7 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask, else mss->private_hugetlb += huge_page_size(hstate_vma(vma)); } + spin_unlock(ptl); return 0; } #else -- 2.53.0