From nobody Fri Dec 19 17:17:59 2025 Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) (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 7B4832F25EF; Thu, 4 Dec 2025 20:18:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.16 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764879516; cv=none; b=eiJ9u7IT6M77DUrEQR43C6Ow7d5VvcGLyjeNgE4AGX0KVEb1GSBwLXuRhsyNTSZS/cecKt05AkS7gBuHmhte8cy84/I74faI3m68tX4sCO5WFXOKpnDE1VRfyPVB19x7WVWxuhYoNEqm6teW6cRO8Eu2WqM25wmFJEX326M4a8k= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764879516; c=relaxed/simple; bh=m01a3N7sCKdndNZkP4mWbWF3+s8UneY6qSCLk4jYhSQ=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type; b=Z8ORtDfIcLG0YWX2Ge/D8l4JE7Bz1Hx0uowA41hiyBFOJWf0NmDLrAZJ3C/W1AcXq7D/2QDTY/dASxTxMy7zroB7Fbn5xKjnLWs9HW03ecvfznN8Ru1Gg/QN+DB0GDPuNO4jINAyQFEtZQvAFgTprzNZSoBZA7QzMOtt/CD67ao= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf20.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 048FE58860; Thu, 4 Dec 2025 20:18:31 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf20.hostedemail.com (Postfix) with ESMTPA id 5961420028; Thu, 4 Dec 2025 20:18:30 +0000 (UTC) Date: Thu, 4 Dec 2025 15:19:35 -0500 From: Steven Rostedt To: LKML , Linux Trace Kernel Cc: Masami Hiramatsu , Mathieu Desnoyers , Douglas Raillard Subject: [PATCH] tracing: Fix fixed array of synthetic event Message-ID: <20251204151935.5fa30355@gandalf.local.home> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) 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 X-Rspamd-Queue-Id: 5961420028 X-Stat-Signature: fynj8u4sn3a8e9gmzpn3mgfdkdnqp1rg X-Rspamd-Server: rspamout08 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX19l2wDywQgfXTsUPJgqk5H1DmE6eC/bUo0= X-HE-Tag: 1764879510-62474 X-HE-Meta: U2FsdGVkX19wD1rlBb5cbQGvgNlTYFBWwiB0UjXW14BxmOE8bMabY5nureb4a8+wC92jMLqYrp7VzK3i7CWTAnkC7K5z2ipVrQrzr5XfY8C3Inm+nwgc1vBJYCZYMCPxh9F0ce0NX0ZuxavWRQM0YbaNIkSH4VqH6LX0gtxPO9hWwIONjy0Ec+2L36BGYzuC2MpFYG5UIODIPO91JOqCj1U0hz6yqeo9V8Miu9c5iWh5Yoitt9rEcrnPWkyrHJWSupEBRRJLUomIOMoYHp6YCveBgZBNcuWVXbRo32zxbuPahRph5zk67z0abi81kiqYF7yqqBE83C/7Sc9BOWn/QLvHAMbEfmWGQq8HGjn/iMOv0PQKO1KPE40QgEY6/0RtS/aT9TTYm1UIH/881bqVFQ== Content-Type: text/plain; charset="utf-8" From: Steven Rostedt The commit 4d38328eb442d ("tracing: Fix synth event printk format for str fields") replaced "%.*s" with "%s" but missed removing the number size of the dynamic and static strings. The commit e1a453a57bc7 ("tracing: Do not add length to print format in synthetic events") fixed the dynamic part but did not fix the static part. That is, with the commands: # echo 's:wake_lat char[] wakee; u64 delta;' >> /sys/kernel/tracing/dynam= ic_events # echo 'hist:keys=3Dpid:ts=3Dcommon_timestamp.usecs if !(common_flags & 0= x18)' > /sys/kernel/tracing/events/sched/sched_waking/trigger # echo 'hist:keys=3Dnext_pid:delta=3Dcommon_timestamp.usecs-$ts:onmatch(s= ched.sched_waking).trace(wake_lat,next_comm,$delta)' > /sys/kernel/tracing/= events/sched/sched_switch/trigger That caused the output of: -0 [001] d..5. 193.428167: wake_lat: wakee=3D(efaul= t)sshd-sessiondelta=3D155 sshd-session-879 [001] d..5. 193.811080: wake_lat: wakee=3D(efaul= t)kworker/u34:5delta=3D58 -0 [002] d..5. 193.811198: wake_lat: wakee=3D(efaul= t)bashdelta=3D91 The commit e1a453a57bc7 fixed the part where the synthetic event had "char[] wakee". But if one were to replace that with a static size string: # echo 's:wake_lat char[16] wakee; u64 delta;' >> /sys/kernel/tracing/dyn= amic_events Where "wakee" is defined as "char[16]" and not "char[]" making it a static size, the code triggered the "(efaul)" again. Remove the added STR_VAR_LEN_MAX size as the string is still going to be nul terminated. Cc: stable@vger.kernel.org Fixes: e1a453a57bc7 ("tracing: Do not add length to print format in synthet= ic events") Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace_events_synth.c | 1 - 1 file changed, 1 deletion(-) diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_= synth.c index 2f19bbe73d27..4554c458b78c 100644 --- a/kernel/trace/trace_events_synth.c +++ b/kernel/trace/trace_events_synth.c @@ -375,7 +375,6 @@ static enum print_line_t print_synth_event(struct trace= _iterator *iter, n_u64++; } else { trace_seq_printf(s, print_fmt, se->fields[i]->name, - STR_VAR_LEN_MAX, (char *)&entry->fields[n_u64].as_u64, i =3D=3D se->n_fields - 1 ? "" : " "); n_u64 +=3D STR_VAR_LEN_MAX / sizeof(u64); --=20 2.51.0