On Sat, 21 Feb 2026 11:33:14 +0800 (CST) <[email protected]> wrote:
> From: Shengming Hu <[email protected]> > > trace_graph_thresh_return() called handle_nosleeptime() and then > delegated to trace_graph_return(), which calls > handle_nosleeptime() again. When sleep-time accounting is > disabled this double-adjusts calltime and can produce bogus > durations (including underflow). > > Fix this by computing rettime once, applying > handle_nosleeptime() only once, using the adjusted calltime > for threshold comparison, and writing the return event > directly via __trace_graph_return() when the threshold is met. > Looks good to me. Acked-by: Masami Hiramatsu (Google) <[email protected]> Thanks! > Fixes: 3c9880f3ab52b ("ftrace: Use a running sleeptime instead of > saving on shadow stack") > Signed-off-by: Shengming Hu <[email protected]> > --- > kernel/trace/trace_functions_graph.c | 14 ++++++++++---- > 1 file changed, 10 insertions(+), 4 deletions(-) > > diff --git a/kernel/trace/trace_functions_graph.c > b/kernel/trace/trace_functions_graph.c > index cbe43680c..b9c81fbd9 100644 > --- a/kernel/trace/trace_functions_graph.c > +++ b/kernel/trace/trace_functions_graph.c > @@ -403,8 +403,12 @@ static void trace_graph_thresh_return(struct > ftrace_graph_ret *trace, > unsigned long *task_var = fgraph_get_task_var(gops); > struct fgraph_times *ftimes; > struct trace_array *tr; > + unsigned int trace_ctx; > + u64 calltime, rettime; > int size; > > + rettime = trace_clock_local(); > + > ftrace_graph_addr_finish(gops, trace); > > if (*task_var & TRACE_GRAPH_NOTRACE) { > @@ -419,11 +423,13 @@ static void trace_graph_thresh_return(struct > ftrace_graph_ret *trace, > tr = gops->private; > handle_nosleeptime(tr, trace, ftimes, size); > > - if (tracing_thresh && > - (trace_clock_local() - ftimes->calltime < tracing_thresh)) > + calltime = ftimes->calltime; > + > + if (tracing_thresh && (rettime - calltime < tracing_thresh)) > return; > - else > - trace_graph_return(trace, gops, fregs); > + > + trace_ctx = tracing_gen_ctx(); > + __trace_graph_return(tr, trace, trace_ctx, calltime, rettime); > } > > static struct fgraph_ops funcgraph_ops = { > -- > 2.25.1 > -- Masami Hiramatsu (Google) <[email protected]>
