From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ULLBsbmj" Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 706E81A7 for ; Thu, 16 Nov 2023 12:04:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1700165050; 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: in-reply-to:in-reply-to:references:references; bh=+4XQ4i8Y5DNwJiAj9ly/ReOTlxs9KYLdEh1NBejN2C4=; b=ULLBsbmjFpAKMFDy1pMo30YfvOIAHW7SFTM+xEGk+YUDy8qhjbOpjyGmTBUlErICP2TxHD QPazj7hRecNE1see8k1TP6+n+LOyhfQRSXF/N2YBlg6A7tqe8FigD9BdsxdipWDpzuoaYw VzGZ5dEOmyshE4KqEM78lRHx4kJDcIs= Received: from mail-oa1-f70.google.com (mail-oa1-f70.google.com [209.85.160.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-302-VT-Vt-3INyqxZjl4VSFwJA-1; Thu, 16 Nov 2023 15:04:08 -0500 X-MC-Unique: VT-Vt-3INyqxZjl4VSFwJA-1 Received: by mail-oa1-f70.google.com with SMTP id 586e51a60fabf-1ef39189888so290145fac.1 for ; Thu, 16 Nov 2023 12:04:08 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1700165048; x=1700769848; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=+4XQ4i8Y5DNwJiAj9ly/ReOTlxs9KYLdEh1NBejN2C4=; b=wQ/wQx9jYhqiz0IrzdGM2Ybmddtg/4k3Wnsj6eztcBMv/+WQQPgGGBgb1K+uErUNg3 Si0Ps9vf88gaPkI6zJjqcNUQd1NmcdOr26Cf5Gusc3GLwrAWCJOtkBuYJ/cEw1FTGDMj VXfAUyCx6mST2PxDp/DczsuZ6rP9Ft21eOUcspeEtHF5oOJcSwxFbKQUSUtBMEwFR+5E ehDsYICUf5xefZAhwQLbTD2HhdeEwjzX6+WICLPGyMLa4WfY4MqpNhSg5Uwe5gCwA0Y8 myB/kEZdDNigrrmHSxG0MbYMptlYV1U0fiwty69Wd4bL9h+73xmzrTjYlbNxCvSoqjtO yfLg== X-Gm-Message-State: AOJu0YxcDoQEV+UD2qH+lwZ36Ys2AMgNC/zlsrtszl0KziJOH47hERd6 3xi8IkTAwUwLR1C7y5CLVJDRSOquW5+HRojs5TQ9oVWweaBXArV56JzzOVRJhOhqt+SnvK8yj2x Koy0sEVme6IFjgy0KZOOq6nhRuw== X-Received: by 2002:a05:6870:2301:b0:1ea:7463:1b8f with SMTP id w1-20020a056870230100b001ea74631b8fmr10381848oao.0.1700165048056; Thu, 16 Nov 2023 12:04:08 -0800 (PST) X-Google-Smtp-Source: AGHT+IHDPS7+wKj9qqDek4+rigv0rYOE1IH7oReMKMjyyoPNCSs/XVBtexRivZXLqhWKUZiqpeXWhA== X-Received: by 2002:a05:6870:2301:b0:1ea:7463:1b8f with SMTP id w1-20020a056870230100b001ea74631b8fmr10381812oao.0.1700165047537; Thu, 16 Nov 2023 12:04:07 -0800 (PST) Received: from x1n (cpe688f2e2cb7c3-cm688f2e2cb7c0.cpe.net.cable.rogers.com. [99.254.121.117]) by smtp.gmail.com with ESMTPSA id j17-20020ac86651000000b0041b3deef647sm33619qtp.8.2023.11.16.12.04.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 16 Nov 2023 12:04:06 -0800 (PST) Date: Thu, 16 Nov 2023 15:04:04 -0500 From: Peter Xu To: David Hildenbrand Cc: Andrew Morton , syzbot , Muhammad Usama Anjum , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, syzkaller-bugs@googlegroups.com, wangkefeng.wang@huawei.com Subject: Re: [syzbot] [mm?] WARNING in unmap_page_range (2) Message-ID: References: <000000000000b0e576060a30ee3b@google.com> <20231115140006.cc7de06f89b1f885f4583af0@linux-foundation.org> <6308590a-d958-4ecc-a478-ba088cf7984d@redhat.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <6308590a-d958-4ecc-a478-ba088cf7984d@redhat.com> On Thu, Nov 16, 2023 at 07:13:44PM +0100, David Hildenbrand wrote: > > It should be fine, as: > > > > static void make_uffd_wp_pte(struct vm_area_struct *vma, > > unsigned long addr, pte_t *pte) > > { > > pte_t ptent = ptep_get(pte); > > > > #ifndef CONFIG_USERFAULTFD_ > > > > if (pte_present(ptent)) { > > pte_t old_pte; > > > > old_pte = ptep_modify_prot_start(vma, addr, pte); > > ptent = pte_mkuffd_wp(ptent); > > ptep_modify_prot_commit(vma, addr, pte, old_pte, ptent); > > } else if (is_swap_pte(ptent)) { > > ptent = pte_swp_mkuffd_wp(ptent); > > set_pte_at(vma->vm_mm, addr, pte, ptent); > > } else { <----------------- this must be pte_none() already > > set_pte_at(vma->vm_mm, addr, pte, > > make_pte_marker(PTE_MARKER_UFFD_WP)); > > } > > } > > Indeed! Is pte_swp_mkuffd_wp() reasonable for pte markers? I rememebr that > we don't support multiple markers yet, so it might be good enough. Not really that reasonable, but nothing harmful either that I see so far; the current code handles any pte marker without caring any of those hint bits. I can also reproduce this syzbot error easily with !UFFD config on x86. Let me send the patchset to fix current known issues first. Thanks, -- Peter Xu