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Message-Id: <20220305010531.2c1f6ac1e96d4be6481924a7@kernel.org>
Date: Sat, 5 Mar 2022 01:05:31 +0900
From: Masami Hiramatsu <mhiramat@...nel.org>
To: Randy Dunlap <rdunlap@...radead.org>
Cc: linux-kernel@...r.kernel.org,
Igor Zhbanov <i.zhbanov@...russia.ru>,
Steven Rostedt <rostedt@...dmis.org>,
Masami Hiramatsu <mhiramat@...nel.org>,
Ingo Molnar <mingo@...hat.com>
Subject: Re: [PATCH] trace: fix return value of __setup handlers
On Wed, 2 Mar 2022 19:17:44 -0800
Randy Dunlap <rdunlap@...radead.org> wrote:
> __setup() handlers should generally return 1 to indicate that the
> boot options have been handled.
>
> Using invalid option values causes the entire kernel boot option
> string to be reported as Unknown and added to init's environment
> strings, polluting it.
>
> Unknown kernel command line parameters "BOOT_IMAGE=/boot/bzImage-517rc6
> kprobe_event=p,syscall_any,$arg1 trace_options=quiet
> trace_clock=jiffies", will be passed to user space.
>
> Run /sbin/init as init process
> with arguments:
> /sbin/init
> with environment:
> HOME=/
> TERM=linux
> BOOT_IMAGE=/boot/bzImage-517rc6
> kprobe_event=p,syscall_any,$arg1
> trace_options=quiet
> trace_clock=jiffies
>
> Return 1 from the __setup() handlers so that init's environment is not
> polluted with kernel boot options.
Oops, thanks for pointing it out.
Acked-by: Masami Hiramatsu <mhiramat@...nel.org>
>
> Fixes: 7bcfaf54f591 ("tracing: Add trace_options kernel command line parameter")
> Fixes: e1e232ca6b8f ("tracing: Add trace_clock=<clock> kernel parameter")
> Fixes: 970988e19eb0 ("tracing/kprobe: Add kprobe_event= boot parameter")
> Signed-off-by: Randy Dunlap <rdunlap@...radead.org>
> Reported-by: Igor Zhbanov <i.zhbanov@...russia.ru>
> Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@...russia.ru
> Cc: Steven Rostedt <rostedt@...dmis.org>
> Cc: Masami Hiramatsu <mhiramat@...nel.org>
> Cc: Ingo Molnar <mingo@...hat.com>
> ---
> "trace_clock=" reports invalid parameter usage later, when it tries
> to use the value:
> Trace clock jiffies not defined, going back to default
>
> kernel/trace/trace.c | 4 ++--
> kernel/trace/trace_kprobe.c | 2 +-
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> --- linux-next-20220302.orig/kernel/trace/trace.c
> +++ linux-next-20220302/kernel/trace/trace.c
> @@ -235,7 +235,7 @@ static char trace_boot_options_buf[MAX_T
> static int __init set_trace_boot_options(char *str)
> {
> strlcpy(trace_boot_options_buf, str, MAX_TRACER_SIZE);
> - return 0;
> + return 1;
> }
> __setup("trace_options=", set_trace_boot_options);
>
> @@ -246,7 +246,7 @@ static int __init set_trace_boot_clock(c
> {
> strlcpy(trace_boot_clock_buf, str, MAX_TRACER_SIZE);
> trace_boot_clock = trace_boot_clock_buf;
> - return 0;
> + return 1;
> }
> __setup("trace_clock=", set_trace_boot_clock);
>
> --- linux-next-20220302.orig/kernel/trace/trace_kprobe.c
> +++ linux-next-20220302/kernel/trace/trace_kprobe.c
> @@ -32,7 +32,7 @@ static int __init set_kprobe_boot_events
> strlcpy(kprobe_boot_events_buf, str, COMMAND_LINE_SIZE);
> disable_tracing_selftest("running kprobe events");
>
> - return 0;
> + return 1;
> }
> __setup("kprobe_event=", set_kprobe_boot_events);
>
--
Masami Hiramatsu <mhiramat@...nel.org>
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