From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 E533A2DB783 for ; Tue, 3 Feb 2026 10:35:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770114929; cv=none; b=GcaIKqXKFwo6lZ5VcoBBSkYjckGF6yV4shfCjsM08tv2zBvf7zQyo2i2OEh5k57Iy+qsw2giv0ucQFGWdK/8zm1nTbRjrv1MBLOI9PpE5ZxrDjkTGv5LUX56KHP7PaHd+xQUMAYrBClFFcpawX6QyBxmdlhOF8vpO4lNGFX91Dw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770114929; c=relaxed/simple; bh=S4nCe9RdyPpAtp7Mp2ZNE6h69mNCvah2U45wBSCykJ8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XnE5tfhsDPdiXxltg8R0Ydo8DLEajN2VbppN5YYuEyjymmWzbCogEAemdYgAjNHHL9qcs/1uIGcE5pIrDnyl3KXl+wwQmbiz3l7mMipc8KdfTGvqJC3Q8gmeo3fMG/BhNFRuqcJukoZr5zErzZmvtwpaSO9Sw9Gj5bQXMyXDqoc= 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=jSFrFHEB; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=pH10+Jm/; arc=none smtp.client-ip=170.10.129.124 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="jSFrFHEB"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="pH10+Jm/" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1770114927; 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=dG/1ixmI6/hveTX8LWUk7DTwV/HbziRIWxtK3JNwm8w=; b=jSFrFHEBUXrUPgTFZ7sfhxlwiVjOhOdkbabF+nGEUmG4cybj45kTKzvW/Nmz/9GQIxFo3o BTHNyxg+3eM9Pnw+gWJFFcW2B1t64pWgRS8jVDZAK3iujfekRSLz+VO+fC5dcD9tkdA+8T mYKSk+Tkb3pRE2JRRF2e/uZZGAYz0bs= Received: from mail-ej1-f71.google.com (mail-ej1-f71.google.com [209.85.218.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-513--S3iLt3TPRm-ZT2AjzhawA-1; Tue, 03 Feb 2026 05:35:25 -0500 X-MC-Unique: -S3iLt3TPRm-ZT2AjzhawA-1 X-Mimecast-MFC-AGG-ID: -S3iLt3TPRm-ZT2AjzhawA_1770114924 Received: by mail-ej1-f71.google.com with SMTP id a640c23a62f3a-b8842248611so535392866b.0 for ; Tue, 03 Feb 2026 02:35:25 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1770114924; x=1770719724; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=dG/1ixmI6/hveTX8LWUk7DTwV/HbziRIWxtK3JNwm8w=; b=pH10+Jm/f8hQkABxYCktl7QB8JLEWz1a3VfSGZEcsNtsaqnU7b4Khg8Cfa8tnRtoNv AlFZiyZJ38E13Loqisa/Pl5hvFe/GFiiwk2sfJu+XdRvP9N05DiAHCOjjPEtftCqYNMt p1gVKGAXY8owYYizdBxUQizehqmc9R/0sOAxho0WJaM6xKE8YPj/2JOIkFdie5ClrN2y L031Hf3BnnQEramOjUk627W7pdLGCPBb6opzgjSAscdIt/Tiij7qxpmkquk3i+P4tEJt nz3s07GSiKoUQQ0Sf21X852vkt3zYQ5JXGZzIKgQ4gFSA05o3dpr4vV4GNwoay1yan/h YrVw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1770114924; x=1770719724; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=dG/1ixmI6/hveTX8LWUk7DTwV/HbziRIWxtK3JNwm8w=; b=W59W9nek31ohQLigWihyKm0zexnsyQcJivT7z+s0hXTkJ1mbQcTg9The08toBti145 LsEvP/6ooaBeU8GXlmMpDPXc4pbsCQquonlgP+tyn5Rcue0OzPsxBouDoBw0L5jBsKt0 PWBDcgn4MFLorS56trVn2TmuZZvuPXtztc6yjSNR15KzZluOaMIxwsfbrhrV5yrRrF4b 2XjRFVHiFXUbasUTPut3QvOd1mKNlx6WVgV4G60YVlcGKo5SoDElpmrtf6f4nCdPgsdo cfi1sQBg6SIZuYwDZZnmL6GmYG2JgvTHHrpOupdGJc/QYC/p5WHN+9/fAJiMcBk26wkj RRrQ== X-Forwarded-Encrypted: i=1; AJvYcCUXQyyKo6MRM3vnpWSqi6DCF73pyD21Vk1ZSq0lr//1P+uLPrv2sY+i9Sxzqv/xOq4lUdCKItsDzKCPnZY=@vger.kernel.org X-Gm-Message-State: AOJu0YxRR0NgHrUfModi+yrErRSvqKIm7P8aA0F6IiIycGnE1mIoFlSM RN7wZW98WzrfPUsU8i5U3qksRYR8UCre60m1S0tgAIemr/hG2yBeU+8omgTI+O+T38/ejidlWvu jLWCMUZDxTWdOErJ1sKXQ22DCHNWeyXCjfHfU4Rqr7E3Q5WweHc1/hBswJR76thonwb/8lqIdNA == X-Gm-Gg: AZuq6aJ8GgtJrC2W82uOQJGagohG4UUt+zO4Nn4he2m4YuDUIELpLUpc0QkHGlbaWmH uIlUPYALVMUmr281gt3ocQkC3xmErhLtC6lBeGN8f3htwyQBhhG9xlaVpo8CouMSXKLqpajUw2e TObeFWHk0WcYaLNkm/8/4p5M+eHZqHPaO00fg0XRXpBMoxz6CUpNya7KfQAY6MW10UU4iy+T7vT HT2ZDQ2Pb9/T33ff7VmdxuJE1imH6szkK0jFQ9WIJRv6WbqtoL1NlBGkvk9bKLJjeMf0ZKsbs7Y 2qxfV0Un4Ulk1iZtaQccw2gY/WTg4bEb5T+eoGyb+JACRDFaWrWk17MoFc2OCGsS0uA+moqZ1pv rz1odLK+YC7nN8MFpM7CCBmQmRlZLQuLNYw== X-Received: by 2002:a17:907:c09:b0:b87:2780:1b1e with SMTP id a640c23a62f3a-b8dff6680aemr922343666b.41.1770114924256; Tue, 03 Feb 2026 02:35:24 -0800 (PST) X-Received: by 2002:a17:907:c09:b0:b87:2780:1b1e with SMTP id a640c23a62f3a-b8dff6680aemr922341966b.41.1770114923761; Tue, 03 Feb 2026 02:35:23 -0800 (PST) Received: from redhat.com (IGLD-80-230-34-155.inter.net.il. [80.230.34.155]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-b8decc368fbsm814985666b.6.2026.02.03.02.35.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Feb 2026 02:35:23 -0800 (PST) Date: Tue, 3 Feb 2026 05:35:20 -0500 From: "Michael S. Tsirkin" To: Arnd Bergmann Cc: Eugenio =?iso-8859-1?Q?P=E9rez?= , Arnd Bergmann , Jason Wang , Xie Yongji , Xuan Zhuo , Anders Roxell , Marco Crivellari , virtualization@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] vduse: fix compat handling for VDUSE_IOTLB_GET_FD/VDUSE_VQ_GET_INFO Message-ID: <20260203053142-mutt-send-email-mst@kernel.org> References: <20260202095940.1358613-1-arnd@kernel.org> <20260202095940.1358613-2-arnd@kernel.org> <30db98bd-8361-46f5-aec1-ffbc4e8574dd@app.fastmail.com> <20260202114412-mutt-send-email-mst@kernel.org> <34d3ce77-84b2-476c-a678-e092831041ae@app.fastmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <34d3ce77-84b2-476c-a678-e092831041ae@app.fastmail.com> On Mon, Feb 02, 2026 at 11:54:17PM +0100, Arnd Bergmann wrote: > On Mon, Feb 2, 2026, at 17:45, Michael S. Tsirkin wrote: > > On Mon, Feb 02, 2026 at 12:59:03PM +0100, Arnd Bergmann wrote: > > > > I think .compat_ioctl would be cleaner frankly. Just look at > > all the ifdefery. And who knows what broken-ness userspace > > comes up with with this approach. Better use the standard approach. > > Sent now. > > I'm not sure it's much better because there is quite a bit of > code duplication, and reducing that would be a larger rework. yes but on the flip side, we can put it all inside ifdef CONFIG_COMPAT (which this code did not do, but should IMHO). > It may be best to hold off on patch 2 for the coming merge window > since the compat ioctl code has apparently always been broken for > x86 here. And it needs testing. > I hope we can at least get patch 1/2 merged along with the > new code though, otherwise it would get a lot harder to sort > it out properly, with the v2 struct members overlapping the > old padding fields. > > Arnd Along with it or no, surely before the release. Given 32 on 64 with this apparently has been broken forever, I will merge this just based on even you did not bother testing compat, I am inclined to say I am merging this but not rebasing because of this. Oh and we got lucky this didn't leak kernel stack info. Eugenio, note for the future: please help make sure UAPI structs do not have hidden padding. -- MST