From mboxrd@z Thu Jan 1 00:00:00 1970 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 5A58C1A3178; Thu, 17 Apr 2025 18:12:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744913536; cv=none; b=LKCiOqYu9v2mw8IC2Q9POpb3pdSvHrZYRZBZYE7gbJLZqkZsQEx8JujHAzCLnuXCY2MZ/zEWvB7cxoA5/Y2z+pKlcdDEc5Xay3mKHn3/135eMYAAzknXT+eOcVmUbBonDI8wLQwsdNXMEVnkNhF8zl5NESFyKKKqOpkiWaFKqYM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744913536; c=relaxed/simple; bh=PmacY0gM9gJW+4lDX64xHZjCUQYRu4vqXHaR8PNbd+0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=r7tXMvMZtNzghfUZ6R7Iaz6SeXYIIHNYscFiauXKTZLiiTpR2KM713Vgiq2P4/sy9VimsCINHOLfiu5QsIy8u0q7zGB2JxdN49W9dPwFQdyDoh911CrlkFownkf0DjGoo1N2BSd7EcQpMCtKrtuSC8ClEb15EMSG+MxP5E0PmgU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=RlBHu2i1; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="RlBHu2i1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C8B63C4CEE4; Thu, 17 Apr 2025 18:12:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1744913536; bh=PmacY0gM9gJW+4lDX64xHZjCUQYRu4vqXHaR8PNbd+0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RlBHu2i1T2O9JZQEUYQV2VVF3u12dlbCe3StxZQbjmMGh0Cql7JVt+0uwKpuln7Oe qsHlcZZ4dlhaVf7YCdd962v7M2+sjqjO7hBXYDwebT87HRgn/2r+jmmOIfh5tayfLl yhFwkR4JgWI0uk+JqAreF4zYive/ICSgiXkQKj94= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mathieu Desnoyers , Tom Zanussi , Douglas Raillard , "Masami Hiramatsu (Google)" , "Steven Rostedt (Google)" Subject: [PATCH 6.14 372/449] tracing: Do not add length to print format in synthetic events Date: Thu, 17 Apr 2025 19:51:00 +0200 Message-ID: <20250417175133.229574074@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250417175117.964400335@linuxfoundation.org> References: <20250417175117.964400335@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Steven Rostedt commit e1a453a57bc76be678bd746f84e3d73f378a9511 upstream. The following causes a vsnprintf fault: # echo 's:wake_lat char[] wakee; u64 delta;' >> /sys/kernel/tracing/dynamic_events # echo 'hist:keys=pid:ts=common_timestamp.usecs if !(common_flags & 0x18)' > /sys/kernel/tracing/events/sched/sched_waking/trigger # echo 'hist:keys=next_pid:delta=common_timestamp.usecs-$ts:onmatch(sched.sched_waking).trace(wake_lat,next_comm,$delta)' > /sys/kernel/tracing/events/sched/sched_switch/trigger Because the synthetic event's "wakee" field is created as a dynamic string (even though the string copied is not). The print format to print the dynamic string changed from "%*s" to "%s" because another location (__set_synth_event_print_fmt()) exported this to user space, and user space did not need that. But it is still used in print_synth_event(), and the output looks like: -0 [001] d..5. 193.428167: wake_lat: wakee=(efault)sshd-sessiondelta=155 sshd-session-879 [001] d..5. 193.811080: wake_lat: wakee=(efault)kworker/u34:5delta=58 -0 [002] d..5. 193.811198: wake_lat: wakee=(efault)bashdelta=91 bash-880 [002] d..5. 193.811371: wake_lat: wakee=(efault)kworker/u35:2delta=21 -0 [001] d..5. 193.811516: wake_lat: wakee=(efault)sshd-sessiondelta=129 sshd-session-879 [001] d..5. 193.967576: wake_lat: wakee=(efault)kworker/u34:5delta=50 The length isn't needed as the string is always nul terminated. Just print the string and not add the length (which was hard coded to the max string length anyway). Cc: stable@vger.kernel.org Cc: Mathieu Desnoyers Cc: Tom Zanussi Cc: Douglas Raillard Acked-by: Masami Hiramatsu (Google) Link: https://lore.kernel.org/20250407154139.69955768@gandalf.local.home Fixes: 4d38328eb442d ("tracing: Fix synth event printk format for str fields"); Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_events_synth.c | 1 - 1 file changed, 1 deletion(-) --- a/kernel/trace/trace_events_synth.c +++ b/kernel/trace/trace_events_synth.c @@ -370,7 +370,6 @@ static enum print_line_t print_synth_eve union trace_synth_field *data = &entry->fields[n_u64]; trace_seq_printf(s, print_fmt, se->fields[i]->name, - STR_VAR_LEN_MAX, (char *)entry + data->as_dynamic.offset, i == se->n_fields - 1 ? "" : " "); n_u64++;