On Sat, 21 Feb 2026 11:30:07 +0800 (CST) <[email protected]> wrote:
> From: Shengming Hu <[email protected]> > > 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. > Good catch! Acked-by: Masami Hiramatsu (Google) <[email protected]> Thanks! > Fixes: b84214890a9bc ("function_graph: Move graph notrace bit to > shadow stack global var") > Signed-off-by: Shengming Hu <[email protected]> > --- > kernel/trace/trace_functions_graph.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/kernel/trace/trace_functions_graph.c > b/kernel/trace/trace_functions_graph.c > index 1de6f1573..cbe43680c 100644 > --- a/kernel/trace/trace_functions_graph.c > +++ b/kernel/trace/trace_functions_graph.c > @@ -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; > } > > -- > 2.25.1 -- Masami Hiramatsu (Google) <[email protected]>
