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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>
Subject: [for-next][PATCH 11/12] ftrace,bug: Improve traceoff_on_warn
Date: Mon, 01 Jun 2020 08:27:40 -0400	[thread overview]
Message-ID: <20200601122808.686678967@goodmis.org> (raw)
In-Reply-To: <20200601122729.727113609@goodmis.org>

From: Peter Zijlstra <peterz@infradead.org>

While doing some tracing, I found a huge portion of the per-cpu buffer
was taken by printk/serial output because we're disabling the trace far
too late (after printing the CUT string).

Improve matters for architectures that have GENERIC_BUG + _BUG_FLAGS by
killing the tracer in the exception handler before printing anything
much.

Link: https://lkml.kernel.org/r/20200528145240.GF706495@hirez.programming.kicks-ass.net

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 lib/bug.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/bug.c b/lib/bug.c
index 8c98af0bf585..7103440c0ee1 100644
--- a/lib/bug.c
+++ b/lib/bug.c
@@ -47,6 +47,7 @@
 #include <linux/bug.h>
 #include <linux/sched.h>
 #include <linux/rculist.h>
+#include <linux/ftrace.h>
 
 extern struct bug_entry __start___bug_table[], __stop___bug_table[];
 
@@ -153,6 +154,8 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)
 	if (!bug)
 		return BUG_TRAP_TYPE_NONE;
 
+	disable_trace_on_warning();
+
 	file = NULL;
 	line = 0;
 	warning = 0;
-- 
2.26.2



  parent reply	other threads:[~2020-06-01 12:28 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-01 12:27 [for-next][PATCH 00/12] tracing: Updates for 5.8 (finally finished testing them) Steven Rostedt
2020-06-01 12:27 ` [for-next][PATCH 01/12] ftrace: show debugging information when panic_on_warn set Steven Rostedt
2020-06-01 12:27 ` [for-next][PATCH 02/12] tools/bootconfig: Add a summary of test cases and return error Steven Rostedt
2020-06-01 12:27 ` [for-next][PATCH 03/12] tracing/probe: reverse arguments to list_add Steven Rostedt
2020-06-01 12:27 ` [for-next][PATCH 04/12] tracing: Check state.disabled in synth event trace functions Steven Rostedt
2020-06-01 12:27 ` [for-next][PATCH 05/12] tracing: Add histogram-design document Steven Rostedt
2020-06-01 12:27 ` [for-next][PATCH 06/12] tracing: Add hist_debug trace event files for histogram debugging Steven Rostedt
2020-06-01 12:27 ` [for-next][PATCH 07/12] tracing/doc: Fix typos in histogram-design.rst Steven Rostedt
2020-06-01 12:27 ` [for-next][PATCH 09/12] tracing: Move synthetic events to a separate file Steven Rostedt
2020-06-01 12:27 ` [for-next][PATCH 10/12] selftests/ftrace: Distinguish between hist and synthetic event checks Steven Rostedt
2020-06-01 12:27 ` Steven Rostedt [this message]
2020-06-01 12:27 ` [for-next][PATCH 12/12] tracing: Add a trace print when traceoff_on_warning is triggered Steven Rostedt

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