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References: <20211120112738.45980-1-laoar.shao@gmail.com> <20211120112738.45980-8-laoar.shao@gmail.com>
 <yt9d35nf1d84.fsf@linux.ibm.com> <20211129123043.5cfd687a@gandalf.local.home>
In-Reply-To: <20211129123043.5cfd687a@gandalf.local.home>
From:   Yafang Shao <laoar.shao@gmail.com>
Date:   Tue, 30 Nov 2021 11:03:48 +0800
Message-ID: <CALOAHbCVJcPdYq2j_VvhHBE-xLBnizRRx2oBu-KNgOr5jMf6RQ@mail.gmail.com>
Subject: Re: [PATCH v2 7/7] tools/testing/selftests/bpf: replace open-coded 16
 with TASK_COMM_LEN
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     Sven Schnelle <svens@linux.ibm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        netdev <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
        "linux-perf-use." <linux-perf-users@vger.kernel.org>,
        linux-fsdevel@vger.kernel.org, Linux MM <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        kernel test robot <oliver.sang@intel.com>,
        kbuild test robot <lkp@intel.com>,
        Andrii Nakryiko <andrii@kernel.org>,
        David Hildenbrand <david@redhat.com>,
        Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>,
        Andrii Nakryiko <andrii.nakryiko@gmail.com>,
        Michal Miroslaw <mirq-linux@rere.qmqm.pl>,
        Peter Zijlstra <peterz@infradead.org>,
        Matthew Wilcox <willy@infradead.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Kees Cook <keescook@chromium.org>,
        Petr Mladek <pmladek@suse.com>,
        Tom Zanussi <zanussi@kernel.org>
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Precedence: bulk

On Tue, Nov 30, 2021 at 1:30 AM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Mon, 29 Nov 2021 11:13:31 +0100
> Sven Schnelle <svens@linux.ibm.com> wrote:
>
>
> > This breaks the trigger-field-variable-support.tc from the ftrace test
> > suite at least on s390:
> >
> > echo 'hist:keys=next_comm:wakeup_lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,next_pid,sched.sched_waking.prio,next_comm) if next_comm=="ping"'
> > linux/tools/testing/selftests/ftrace/test.d/trigger/inter-event/trigger-field-variable-support.tc: line 15: echo: write error: Invalid argument
> >
> > I added a debugging line into check_synth_field():
> >
> > [   44.091037] field->size 16, hist_field->size 16, field->is_signed 1, hist_field->is_signed 0
> >
> > Note the difference in the signed field.
>
> That should not break on strings.
>
> Does this fix it (if you keep the patch)?
>
> -- Steve
>
> diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
> index 9555b8e1d1e3..319f9c8ca7e7 100644
> --- a/kernel/trace/trace_events_hist.c
> +++ b/kernel/trace/trace_events_hist.c
> @@ -3757,7 +3757,7 @@ static int check_synth_field(struct synth_event *event,
>
>         if (strcmp(field->type, hist_field->type) != 0) {
>                 if (field->size != hist_field->size ||
> -                   field->is_signed != hist_field->is_signed)
> +                   (!field->is_string && field->is_signed != hist_field->is_signed))
>                         return -EINVAL;
>         }
>

Many thanks for the quick fix!
It seems this fix should be ahead of patch #7.
I will send v3 which contains your fix.

-- 
Thanks
Yafang