From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 A5D2D2701DC for ; Mon, 6 Jul 2026 15:45:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783352715; cv=none; b=IRioOdDo4w2Sp/PJNfzkKsX+V2kReCdcPBsxN1pokMXL3ANdcLEDBO3dRvDUwkpyYm6BDZ+QOuswBG8EfdUYNaFq0CKHC4Pjsm4zQdY/JGMJQ2TqK8LHsmB5EAG5pMXCkChoPTtzwdYtbRrnoD2T9J02BN/ACSL7XhQPDg/TzGc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783352715; c=relaxed/simple; bh=Wvw4KQ4xDEf8xjkcXI3OHWUJDI9OwTK73Tc4+PLrvHM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=JUCAGxAQUMp+h9sESVChQp6q+CWhVajzLgEPe465yInB49Zh1oRR6zrjJ1yFe2fykR9z6ttXLOmqGnpfJHhx21zQcqW21AttTTy003uSNgHLU0p+d99sMbHus5teF+qzd3w7BIGePlhPKWvZrR7cMbfJAjWU+wIM35HJDBdnPms= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=E+qdg4gD; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="E+qdg4gD" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1783352713; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=BezWf31aY4w6w/a+lqeQnI/w17h6Fee4KI8S5RVgbig=; b=E+qdg4gDeCYla3SUkegw/uQa7HsT8MZZMdRXeKyjQTlc4WQsap8sfDfdeVxYrv1MXQCGz8 KSp4vDbtnZiNp06zXBvsta6BV3arhhpTzwpxC2bmTeNDpodLgRwSxvJjYuNsojt9QGg0Fr V9fiya5YgLhDHPYziCqJnAU8+OnAr7c= Received: from mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-510-6sLrIIyvOgODbJ2HxQVQoA-1; Mon, 06 Jul 2026 11:45:08 -0400 X-MC-Unique: 6sLrIIyvOgODbJ2HxQVQoA-1 X-Mimecast-MFC-AGG-ID: 6sLrIIyvOgODbJ2HxQVQoA_1783352705 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id AFBF11955DC3; Mon, 6 Jul 2026 15:45:05 +0000 (UTC) Received: from p1.redhat.com (unknown [10.22.58.4]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 67988195604B; Mon, 6 Jul 2026 15:44:57 +0000 (UTC) From: Nico Pache To: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: Nico Pache , David Hildenbrand , Andrew Morton , Lorenzo Stoakes , Zi Yan , Baolin Wang , "Liam R. Howlett" , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Shuah Khan Subject: [PATCH 6/8] mm/khugepaged: unmap pte before releasing vma write lock Date: Mon, 6 Jul 2026 09:44:53 -0600 Message-ID: <20260706154500.39178-7-npache@redhat.com> In-Reply-To: <20260706154500.39178-1-npache@redhat.com> References: <20260706154500.39178-1-npache@redhat.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 We are currently dropping the anon_vma write lock before unmapping the PTE. Although this is safe, due to us still holding the mmap_write_lock, its safer and less confusing to switch the order of these two operations. Suggested-by: David Hildenbrand Signed-off-by: Nico Pache --- mm/khugepaged.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index c4ea2dc1591b..3c6f1254deca 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1548,10 +1548,10 @@ static enum scan_result collapse_huge_page(struct mm_struct *mm, unsigned long s result = SCAN_SUCCEED; out_up_write: - if (anon_vma_locked) - anon_vma_unlock_write(vma->anon_vma); if (pte) pte_unmap(pte); + if (anon_vma_locked) + anon_vma_unlock_write(vma->anon_vma); mmap_write_unlock(mm); out_nolock: if (folio) -- 2.54.0