From: Randy Dunlap rdunlap@infradead.org
__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.
Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru Link: https://lkml.kernel.org/r/20220303031744.32356-1-rdunlap@infradead.org
Cc: stable@vger.kernel.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@infradead.org Reported-by: Igor Zhbanov i.zhbanov@omprussia.ru Acked-by: Masami Hiramatsu mhiramat@kernel.org Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org --- kernel/trace/trace.c | 4 ++-- kernel/trace/trace_kprobe.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 3050892d1812..eb44418574f9 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -235,7 +235,7 @@ static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata; 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(char *str) { 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);
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 508f14af4f2c..b62fd785b599 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -32,7 +32,7 @@ static int __init set_kprobe_boot_events(char *str) 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);