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fgraph: Fix thresh_return clear per-task notrace

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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: b84214890a ("function_graph: Move graph notrace bit to shadow stack global var")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Shengming Hu <hu.shengming@zte.com.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Shengming Hu 2026-02-21 11:30:07 +08:00 • committed by Steven Rostedt (Google)
parent 11439c4635
commit 6ca8379b5d
1 changed files with 3 additions and 2 deletions
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5
kernel/trace/trace_functions_graph.c
View file

@ -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;
}