From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 1FAAC539F for ; Tue, 4 Jul 2023 09:42:14 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BD62510D5 for ; Tue, 4 Jul 2023 02:41:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1688463709; 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=zLSEosjlinrCxKCLRBdlkkdM07HJXUp3DKjWoDpchWo=; b=Q8xgGU/mnJHWe/a7CXjCpQguvg2z0t4wWZqzNs49POXMPSR2atVHyOpJaT8YK/WxL/Omh2 8a4hZrJjcTyuVdGT3pSPXGK0CEhSNu+NCbO76LbYra3etGPxx2v1B9vpGmJkVFiGFwzAj3 abiKvMARplFadCvd4Z+tUjbIy3i9yL0= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-447-UDuYkHNINm63hneICkQI6g-1; Tue, 04 Jul 2023 05:41:47 -0400 X-MC-Unique: UDuYkHNINm63hneICkQI6g-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6201C3814950; Tue, 4 Jul 2023 09:41:47 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.42.28.195]) by smtp.corp.redhat.com (Postfix) with ESMTP id 81309492C13; Tue, 4 Jul 2023 09:41:46 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: References: <1357760.1688460637@warthog.procyon.org.uk> To: Herbert Xu Cc: dhowells@redhat.com, Ondrej Mosnacek , Linux Crypto Mailing List , Paolo Abeni , netdev@vger.kernel.org, Linux Kernel Mailing List , regressions@lists.linux.dev Subject: Re: Regression bisected to "crypto: af_alg: Convert af_alg_sendpage() to use MSG_SPLICE_PAGES" Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-ID: <1361503.1688463705.1@warthog.procyon.org.uk> Date: Tue, 04 Jul 2023 10:41:45 +0100 Message-ID: <1361504.1688463705@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, RCVD_IN_MSPIKE_H4,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Herbert Xu wrote: > All it's saying is that if you modify the data after sending it off > via splice then the data that will be on the wire is undefined. Er, no. It can literally remove the page from the process's VM and paste it somewhere else - though in this case, that shouldn't happen. However, the buffer passed to SPLICE_F_GIFT should also be page-aligned, which it might not be because they used calloc(). There's no reason to use SPLICE_F_GIFT here. vmsplice() still attaches the > There is no reason why this should crash. Agreed. I'm still looking at it. Interestingly, the output comes out the same, no matter whether vmsplice(), vmsplice() + SPLICE_F_GIFT or writev(), so it looks like the buffers get to > If we can't fix this the patches should be reverted. I didn't change vmsplice() or the way pages are stored in the pipe. And, note, there are also a bunch of GUP changes that could have an effect. David