[PATCH v6 1/6] tracing: Do not bother getting user space stacktraces for kernel threads

[Steven Rostedt <rostedt@kernel.org>]

From: Steven Rostedt <rostedt@goodmis.org>

If a user space stacktrace is requested when running a kernel thread, just
return, as there's no point trying to get the user space stacktrace as
there is no user space.

Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
Changes since v5: https://lore.kernel.org/20250424192613.014380756@goodmis.org

- Also add check for PF_USER_WORKER to test for kernel thread

 kernel/trace/trace.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 1b7db732c0b1..2cca29c9863d 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3138,6 +3138,10 @@ ftrace_trace_userstack(struct trace_array *tr,
 	if (!(tr->trace_flags & TRACE_ITER_USERSTACKTRACE))
 		return;
 
+	/* No point doing user space stacktraces on kernel threads */
+	if (current->flags & (PF_KTHREAD | PF_USER_WORKER))
+		return;
+
 	/*
 	 * NMIs can not handle page faults, even with fix ups.
 	 * The save user stack can (and often does) fault.
-- 
2.50.1