From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 45A9847A64; Mon, 24 Jun 2024 22:57:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719269856; cv=none; b=kAIGuzyXaPHO8Si4fD2CB9hm8WbHxnFftBEcCr2DWY1i8HMRXf4K8SeN4fUZtPAJJHkkrdq1703cUlhBK8jXDWKeI8Z119ltUW5RYjerI2Bf7da3iZp5ELXNItp9afkzWRSwN9w64u0g3WZy6rVsCz6I71d/RtyZq9eQZbrVxgU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719269856; c=relaxed/simple; bh=EoGCiuCUqCOahZlHGiZn0NU6mzQ3qIP8gF3nsrpABCc=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=F/erihp7MiPBnS2CeSSpo2QqCZRGh+b+m5/qcs28VY/jUpMPCG39AZHFRjN8E5knbtjzP5OoEMyOC7DpgLQIDb/am47usE1a7BKZWOw4BKvOcvY4/zk725j965ofWnkEmMdJoc1lAkMnoHUaVmlnTr26b2YVGbKpC2E72lueRnA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=M+ii0MEY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="M+ii0MEY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 446C4C2BBFC; Mon, 24 Jun 2024 22:57:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1719269855; bh=EoGCiuCUqCOahZlHGiZn0NU6mzQ3qIP8gF3nsrpABCc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=M+ii0MEY3a4aLmXaLBAbJ+qg46e/jNWyjWXNNy6YZ2uredvUQaSOkk1hmlP1/8BXA FJBhL55E22poQrelNPt27QnCIHjromd2chCYd/2oYoW1fqL5ojLpUWWXNDLDc0V5Gb 0IO8499jZ7gedxsciTP4QeUfRAzECbUVJRwKLHC0= Date: Mon, 24 Jun 2024 15:57:34 -0700 From: Andrew Morton To: Peter Xu Cc: Audra Mitchell , viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz, aarcange@redhat.com, rppt@linux.vnet.ibm.com, shli@fb.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, shuah@kernel.org, linux-kselftest@vger.kernel.org, raquini@redhat.com Subject: Re: [PATCH v2 1/3] Fix userfaultfd_api to return EINVAL as expected Message-Id: <20240624155734.c93d8297922575a5b25797e1@linux-foundation.org> In-Reply-To: References: <20240621181224.3881179-1-audra@redhat.com> <20240621180330.6993d5fd0bda4da230e45f0d@linux-foundation.org> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) 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=US-ASCII Content-Transfer-Encoding: 7bit On Sun, 23 Jun 2024 11:26:37 -0400 Peter Xu wrote: > > > Fixes: e06f1e1dd499 ("userfaultfd: wp: enabled write protection in userfaultfd API") > > > > A userspace-triggerable WARN is bad. I added cc:stable to this. > > Andrew, > > Note that this change may fix a WARN, but it may also start to break > userspace which might be worse if it happens, IMHO. I forgot to mention > that here, but only mentioned that in v1, and from that POV not copying > stable seems the right thing. > > https://lore.kernel.org/all/ZjuIEH8TW2tWcqXQ@x1n/ > > In summary: I think we can stick with Fixes on e06f1e1dd499, but we > don't copy stable. The major reason we don't copy stable here is > not only about complexity of such backport, but also that there can > be apps trying to pass in unsupported bits (even if the kernel > didn't support it) but keep using MISSING mode only, then we > shouldn't fail them easily after a stable upgrade. Just smells > dangerous to backport. OK. And I'll move it into the 6.11-rc1 queue, for the next merge window.