From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: "Steven Rostedt (Google)" <rostedt@goodmis.org>,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Sasha Levin <sashal@kernel.org>,
linux-trace-kernel@vger.kernel.org
Subject: [PATCH AUTOSEL 4.14 4/6] tracing: Have large events show up as '[LINE TOO BIG]' instead of nothing
Date: Mon, 18 Dec 2023 07:47:21 -0500 [thread overview]
Message-ID: <20231218124725.1382738-4-sashal@kernel.org> (raw)
In-Reply-To: <20231218124725.1382738-1-sashal@kernel.org>
From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
[ 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 <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 c5fe020336bea..755d6146c738c 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3826,7 +3826,11 @@ 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
next prev parent reply other threads:[~2023-12-18 12:47 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-18 12:47 [PATCH AUTOSEL 4.14 1/6] clk: rockchip: rk3128: Fix HCLK_OTG gate register Sasha Levin
2023-12-18 12:47 ` Sasha Levin
2023-12-18 12:47 ` Sasha Levin
2023-12-18 12:47 ` [PATCH AUTOSEL 4.14 2/6] jbd2: correct the printing of write_flags in jbd2_write_superblock() Sasha Levin
2023-12-18 12:47 ` [PATCH AUTOSEL 4.14 3/6] drm/crtc: Fix uninit-value bug in drm_mode_setcrtc Sasha Levin
2023-12-18 12:47 ` Sasha Levin
2023-12-19 8:44 ` Jani Nikula
2023-12-19 8:44 ` Jani Nikula
2024-01-15 3:24 ` Sasha Levin
2024-01-15 3:24 ` Sasha Levin
2024-01-16 10:46 ` End of 4.14 autosel? " Pavel Machek
2024-01-16 10:46 ` Pavel Machek
2023-12-18 12:47 ` Sasha Levin [this message]
2023-12-18 12:47 ` [PATCH AUTOSEL 4.14 5/6] tracing: Add size check when printing trace_marker output Sasha Levin
2023-12-18 12:47 ` [PATCH AUTOSEL 4.14 6/6] ring-buffer: Do not record in NMI if the arch does not support cmpxchg in NMI Sasha Levin
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