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 5DE0A132C0C; Tue, 23 Jan 2024 00:01:44 +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=1705968104; cv=none; b=p0iKRv5JDwPxTpALNxUuS43rvJeOLm/0aNR/+yYW00VzsxDftI5H9UKAL21ptsOAA3WmrLNRUVyPqSgfERkxrxscak0gqSbGRSUi8LyuXZvHPSKZxdUmmGcZ7OH4o1NOtIgLafhIBa/ABZDdZVgT6gNdEiHG098KPRZddnTNwZs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705968104; c=relaxed/simple; bh=8HJzLURa5P1aYEpGm7s3/UEFOkh2EwudchDXXdhLIpo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WxshKvXndf2MTxHaaBBbmo41djBHRsOyc4+MiLwqVVI2u7DGZDipMO67R/tTQoVC8AT46A3uYElM+bH5OdfCCEuMrhFNo9EKY2QzQxE/yrKcCL3R5w4qSPwZH8hq9o7O/Y8YVfYmKrRHjLxVXONQetOLwzKf8NnmV6bpiCNJ69w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=UOvC08oZ; 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="UOvC08oZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 962DEC4AF69; Tue, 23 Jan 2024 00:01:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1705968103; bh=8HJzLURa5P1aYEpGm7s3/UEFOkh2EwudchDXXdhLIpo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UOvC08oZ+MKQs39sdBrmAr4kYluF3L63JrIPZnK3OLpLg8QtnBCKego4t8Gklv20k dzttV+HOBbM1eFrgwx6Hyt9vD5q8NeRHbpYp5mPEPaQPiP+T7OoruqVbHvIesJal4C BzZCVEPtH8EdFKmuQh2shqiGA4H+xGzNPGVhEpFg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mark Rutland , Mathieu Desnoyers , "Masami Hiramatsu (Google)" , "Steven Rostedt (Google)" , Sasha Levin Subject: [PATCH 4.19 012/148] tracing: Have large events show up as [LINE TOO BIG] instead of nothing Date: Mon, 22 Jan 2024 15:56:08 -0800 Message-ID: <20240122235712.939955066@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240122235712.442097787@linuxfoundation.org> References: <20240122235712.442097787@linuxfoundation.org> User-Agent: quilt/0.67 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 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Steven Rostedt (Google) [ Upstream commit b55b0a0d7c4aa2dac3579aa7e6802d1f57445096 ] If a large event was added to the ring buffer that is larger than what the trace_seq can handle, it just drops the output: ~# cat /sys/kernel/tracing/trace # tracer: nop # # entries-in-buffer/entries-written: 2/2 #P:8 # # _-----=> irqs-off/BH-disabled # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / _-=> migrate-disable # |||| / delay # TASK-PID CPU# ||||| TIMESTAMP FUNCTION # | | | ||||| | | <...>-859 [001] ..... 141.118951: tracing_mark_write <...>-859 [001] ..... 141.148201: tracing_mark_write: 78901234 Instead, catch this case and add some context: ~# cat /sys/kernel/tracing/trace # tracer: nop # # entries-in-buffer/entries-written: 2/2 #P:8 # # _-----=> irqs-off/BH-disabled # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / _-=> migrate-disable # |||| / delay # TASK-PID CPU# ||||| TIMESTAMP FUNCTION # | | | ||||| | | <...>-852 [001] ..... 121.550551: tracing_mark_write[LINE TOO BIG] <...>-852 [001] ..... 121.550581: tracing_mark_write: 78901234 This now emulates the same output as trace_pipe. Link: https://lore.kernel.org/linux-trace-kernel/20231209171058.78c1a026@gandalf.local.home Cc: Mark Rutland Cc: Mathieu Desnoyers Reviewed-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin --- kernel/trace/trace.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index b43d681b072f..e6b2d443bab9 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3828,7 +3828,11 @@ static int s_show(struct seq_file *m, void *v) iter->leftover = ret; } else { - print_trace_line(iter); + ret = print_trace_line(iter); + if (ret == TRACE_TYPE_PARTIAL_LINE) { + iter->seq.full = 0; + trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n"); + } ret = trace_print_seq(m, &iter->seq); /* * If we overflow the seq_file buffer, then it will -- 2.43.0