From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AC2DEC43603 for ; Wed, 18 Dec 2019 15:24:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8614824672 for ; Wed, 18 Dec 2019 15:24:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727030AbfLRPY0 (ORCPT ); Wed, 18 Dec 2019 10:24:26 -0500 Received: from mail.kernel.org ([198.145.29.99]:58438 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726960AbfLRPY0 (ORCPT ); Wed, 18 Dec 2019 10:24:26 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4E47621582; Wed, 18 Dec 2019 15:24:25 +0000 (UTC) Date: Wed, 18 Dec 2019 10:24:23 -0500 From: Steven Rostedt To: Sven Schnelle Cc: linux-trace-devel@vger.kernel.org Subject: Re: [PATCH 3/3] ftrace: fix endianness bug in histogram trigger Message-ID: <20191218102423.755eefdc@gandalf.local.home> In-Reply-To: <20191218074427.96184-4-svens@linux.ibm.com> References: <20191218074427.96184-1-svens@linux.ibm.com> <20191218074427.96184-4-svens@linux.ibm.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-trace-devel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-trace-devel@vger.kernel.org On Wed, 18 Dec 2019 08:44:27 +0100 Sven Schnelle wrote: > At least on PA-RISC and s390 synthetic histogram triggers are failing > selftests because trace_event_raw_event_synth() always writes a 64 bit > values, but the reader expects a field->size sized value. On little endian > machines this doesn't hurt, but on big endian this makes the reader always > read zero values. Does this fix make the other one obsolete? https://lore.kernel.org/r/20191211110959.2baeb70f@gandalf.local.home -- Steve > > Signed-off-by: Sven Schnelle > --- > kernel/trace/trace_events_hist.c | 21 ++++++++++++++++++++- > 1 file changed, 20 insertions(+), 1 deletion(-) > > diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c > index f49d1a36d3ae..f62de5f43e79 100644 > --- a/kernel/trace/trace_events_hist.c > +++ b/kernel/trace/trace_events_hist.c > @@ -911,7 +911,26 @@ static notrace void trace_event_raw_event_synth(void *__data, > strscpy(str_field, str_val, STR_VAR_LEN_MAX); > n_u64 += STR_VAR_LEN_MAX / sizeof(u64); > } else { > - entry->fields[n_u64] = var_ref_vals[var_ref_idx + i]; > + struct synth_field *field = event->fields[i]; > + u64 val = var_ref_vals[var_ref_idx + i]; > + > + switch (field->size) { > + case 1: > + *(u8 *)&entry->fields[n_u64] = (u8)val; > + break; > + > + case 2: > + *(u16 *)&entry->fields[n_u64] = (u16)val; > + break; > + > + case 4: > + *(u32 *)&entry->fields[n_u64] = (u32)val; > + break; > + > + default: > + entry->fields[n_u64] = val; > + break; > + } > n_u64++; > } > }