From: Shengming Hu Date: Fri, 13 Feb 2026 06:29:32 +0000 (+0800) Subject: function_graph: Restore direct mode when callbacks drop to one X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=53b2fae90ff01fede6520ca744ed5e8e366497ba;p=thirdparty%2Fkernel%2Fstable.git function_graph: Restore direct mode when callbacks drop to one When registering a second fgraph callback, direct path is disabled and array loop is used instead. When ftrace_graph_active falls back to one, we try to re-enable direct mode via ftrace_graph_enable_direct(true, ...). But ftrace_graph_enable_direct() incorrectly disables the static key rather than enabling it. This leaves fgraph_do_direct permanently off after first multi-callback transition, so direct fast mode is never restored. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260213142932519cuWSpEXeS4-UnCvNXnK2P@zte.com.cn Fixes: cc60ee813b503 ("function_graph: Use static_call and branch to optimize entry function") Signed-off-by: Shengming Hu Signed-off-by: Steven Rostedt (Google) --- diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index cc48d16be43e..4df766c690f9 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -1303,7 +1303,7 @@ static void ftrace_graph_enable_direct(bool enable_branch, struct fgraph_ops *go static_call_update(fgraph_func, func); static_call_update(fgraph_retfunc, retfunc); if (enable_branch) - static_branch_disable(&fgraph_do_direct); + static_branch_enable(&fgraph_do_direct); } static void ftrace_graph_disable_direct(bool disable_branch)