Commit 6ca8379b authored by Shengming Hu's avatar Shengming Hu Committed by Steven Rostedt (Google)
Browse files

fgraph: Fix thresh_return clear per-task notrace 

When tracing_thresh is enabled, function graph tracing uses
trace_graph_thresh_return() as the return handler. Unlike
trace_graph_return(), it did not clear the per-task TRACE_GRAPH_NOTRACE
flag set by the entry handler for set_graph_notrace addresses. This could
leave the task permanently in "notrace" state and effectively disable
function graph tracing for that task.

Mirror trace_graph_return()'s per-task notrace handling by clearing
TRACE_GRAPH_NOTRACE and returning early when set.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260221113007819YgrZsMGABff4Rc-O_fZxL@zte.com.cn


Fixes: b8421489 ("function_graph: Move graph notrace bit to shadow stack global var")
Acked-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: default avatarShengming Hu <hu.shengming@zte.com.cn>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 11439c46

kernel/trace/trace_functions_graph.c

+3 −2
Original line number Diff line number Diff line
@@ -400,14 +400,15 @@ static void trace_graph_thresh_return(struct ftrace_graph_ret *trace, 
				      struct fgraph_ops *gops,

				      struct ftrace_regs *fregs)

{

	unsigned long *task_var = fgraph_get_task_var(gops);

	struct fgraph_times *ftimes;

	struct trace_array *tr;

	int size;



	ftrace_graph_addr_finish(gops, trace);



	if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {

		trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);

	if (*task_var & TRACE_GRAPH_NOTRACE) {

		*task_var &= ~TRACE_GRAPH_NOTRACE;

		return;

	}