From nobody Fri Dec 19 12:31:44 2025 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 DE627208D0 for ; Tue, 19 Dec 2023 14:32:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7B376C433CA; Tue, 19 Dec 2023 14:32:00 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.97) (envelope-from ) id 1rFb9X-00000003MER-2HJA; Tue, 19 Dec 2023 09:32:59 -0500 Message-ID: <20231219143259.319621961@goodmis.org> User-Agent: quilt/0.67 Date: Tue, 19 Dec 2023 09:32:35 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton Subject: [for-next][PATCH 02/10] ring-buffer: Add offset of events in dump on mismatch References: <20231219143233.204534014@goodmis.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: "Steven Rostedt (Google)" On bugs that have the ring buffer timestamp get out of sync, the config CONFIG_RING_BUFFER_VALIDATE_TIME_DELTAS, that checks for it and if it is detected it causes a dump of the bad sub buffer. It shows each event and their timestamp as well as the delta in the event. But it's also good to see the offset into the subbuffer for that event to know if how close to the end it is. Also print where the last event actually ended compared to where it was expected to end. Link: https://lore.kernel.org/linux-trace-kernel/20231211131623.59eaebd2@ga= ndalf.local.home Cc: Mark Rutland Cc: Mathieu Desnoyers Acked-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ring_buffer.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 83eab547f1d1..bfe2697a92ee 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -3358,29 +3358,34 @@ static void dump_buffer_page(struct buffer_data_pag= e *bpage, case RINGBUF_TYPE_TIME_EXTEND: delta =3D rb_event_time_stamp(event); ts +=3D delta; - pr_warn(" [%lld] delta:%lld TIME EXTEND\n", ts, delta); + pr_warn(" 0x%x: [%lld] delta:%lld TIME EXTEND\n", + e, ts, delta); break; =20 case RINGBUF_TYPE_TIME_STAMP: delta =3D rb_event_time_stamp(event); ts =3D rb_fix_abs_ts(delta, ts); - pr_warn(" [%lld] absolute:%lld TIME STAMP\n", ts, delta); + pr_warn(" 0x%x: [%lld] absolute:%lld TIME STAMP\n", + e, ts, delta); break; =20 case RINGBUF_TYPE_PADDING: ts +=3D event->time_delta; - pr_warn(" [%lld] delta:%d PADDING\n", ts, event->time_delta); + pr_warn(" 0x%x: [%lld] delta:%d PADDING\n", + e, ts, event->time_delta); break; =20 case RINGBUF_TYPE_DATA: ts +=3D event->time_delta; - pr_warn(" [%lld] delta:%d\n", ts, event->time_delta); + pr_warn(" 0x%x: [%lld] delta:%d\n", + e, ts, event->time_delta); break; =20 default: break; } } + pr_warn("expected end:0x%lx last event actually ended at:0x%x\n", tail, e= ); } =20 static DEFINE_PER_CPU(atomic_t, checking); --=20 2.42.0