Commit 8f8c9e71 authored Feb 09, 2022 by JaeSang Yoo Committed by Greg Kroah-Hartman Feb 23, 2022

tracing: Fix tp_printk option related with tp_printk_stop_on_boot

[ Upstream commit 3203ce39ac0b2a57a84382ec184c7d4a0bede175 ]

The kernel parameter "tp_printk_stop_on_boot" starts with "tp_printk" which is
the same as another kernel parameter "tp_printk". If "tp_printk" setup is
called before the "tp_printk_stop_on_boot", it will override the latter
and keep it from being set.

This is similar to other kernel parameter issues, such as:
  Commit 745a600c ("um: console: Ignore console= option")
or init/do_mounts.c:45 (setup function of "ro" kernel param)

Fix it by checking for a "_" right after the "tp_printk" and if that
exists do not process the parameter.

Link: https://lkml.kernel.org/r/20220208195421.969326-1-jsyoo5b@gmail.com



Signed-off-by: JaeSang Yoo <jsyoo5b@gmail.com>
[ Fixed up change log and added space after if condition ]
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 9c2a3c94

kernel/trace/trace.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -232,6 +232,10 @@ __setup("trace_clock=", set_trace_boot_clock);

		static int __init set_tracepoint_printk(char *str)
		{
		/* Ignore the "tp_printk_stop_on_boot" param */
		if (*str == '_')
		return 0;

		if ((strcmp(str, "=0") != 0 && strcmp(str, "=off") != 0))
		tracepoint_printk = 1;
		return 1;