From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexei Starovoitov Subject: Re: [PATCH net] ebpf, x86: fix general protection fault when tail call is invoked Date: Tue, 28 Jul 2015 10:02:08 -0700 Message-ID: <55B7B590.8030600@plumgrid.com> References: <23a2630be3c3d41932b9df134f06b9b44671b55e.1438088105.git.daniel@iogearbox.net> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Daniel Borkmann , davem@davemloft.net Return-path: Received: from mail-pa0-f53.google.com ([209.85.220.53]:35704 "EHLO mail-pa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752710AbbG1RCL (ORCPT ); Tue, 28 Jul 2015 13:02:11 -0400 Received: by pabkd10 with SMTP id kd10so72790852pab.2 for ; Tue, 28 Jul 2015 10:02:11 -0700 (PDT) In-Reply-To: <23a2630be3c3d41932b9df134f06b9b44671b55e.1438088105.git.daniel@iogearbox.net> Sender: netdev-owner@vger.kernel.org List-ID: On 7/28/15 6:26 AM, Daniel Borkmann wrote: > After patch, disassembly: > > [...] > 9e: lea 0x80(%rsi,%rdx,8),%rax <--- CONFIG_LOCKDEP/CONFIG_LOCK_STAT > 48 8d 84 d6 80 00 00 00 > a6: mov (%rax),%rax > 48 8b 00 > [...] > > [...] > 9e: lea 0x50(%rsi,%rdx,8),%rax <--- No CONFIG_LOCKDEP > 48 8d 84 d6 50 00 00 00 > a6: mov (%rax),%rax > 48 8b 00 > [...] > > Fixes: b52f00e6a715 ("x86: bpf_jit: implement bpf_tail_call() helper") > Signed-off-by: Daniel Borkmann Thanks for fixing it. Most of my development is actually with LOCKDEP on, but I don't ever turn LOCK_STAT on, so sadly missed this 48 byte increase of 80 byte structure :( Acked-by: Alexei Starovoitov