| tick_program_event() { 1) | clockevents_program_event() { 1) 1.044 us | ktime_get(); 1) 6.481 us | lapic_next_event(); 1) + 10.114 us | } 1) + 11.790 us | } 1) ! 181.223 us | } /* hrtimer_interrupt */ 1) ! 184.624 us | } /* __sysvec_apic_timer_interrupt */ 1) | irq_exit_rcu() { 1) 0.678 us | preempt_count_sub(); When it should still only be tracing the schedule() function. To fix this, add a macro FGRAPH_NO_DIRECT to be set to 0 when the architecture does not support function graph use of ftrace_ops, and set to 1 otherwise. Then use this macro to know to allow function graph tracer to call the handlers directly or not. Cc: stable@vger.kernel.org Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Mark Rutland Link: https://patch.msgid.link/20260218104244.5f14dade@gandalf.local.home Fixes: cc60ee813b503 ("function_graph: Use static_call and branch to optimize entry function") Signed-off-by: Steven Rostedt (Google) Signed-off-by: Sasha Levin --- include/linux/ftrace.h | 13 ++++++++++--- kernel/trace/fgraph.c | 12 +++++++++++- 2 files changed, 21 insertions(+), 4 deletions(-) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index fa74ae5cc9dae..d029afcd22a5d 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -1064,10 +1064,17 @@ static inline bool is_ftrace_trampoline(unsigned long addr) #ifdef CONFIG_FUNCTION_GRAPH_TRACER #ifndef ftrace_graph_func -#define ftrace_graph_func ftrace_stub -#define FTRACE_OPS_GRAPH_STUB FTRACE_OPS_FL_STUB +# define ftrace_graph_func ftrace_stub +# define FTRACE_OPS_GRAPH_STUB FTRACE_OPS_FL_STUB +/* + * The function graph is called every time the function tracer is called. + * It must always test the ops hash and cannot just directly call + * the handler. + */ +# define FGRAPH_NO_DIRECT 1 #else -#define FTRACE_OPS_GRAPH_STUB 0 +# define FTRACE_OPS_GRAPH_STUB 0 +# define FGRAPH_NO_DIRECT 0 #endif #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c index 4df766c690f92..40d373d65f9b9 100644 --- a/kernel/trace/fgraph.c +++ b/kernel/trace/fgraph.c @@ -539,7 +539,11 @@ static struct fgraph_ops fgraph_stub = { static struct fgraph_ops *fgraph_direct_gops = &fgraph_stub; DEFINE_STATIC_CALL(fgraph_func, ftrace_graph_entry_stub); DEFINE_STATIC_CALL(fgraph_retfunc, ftrace_graph_ret_stub); +#if FGRAPH_NO_DIRECT +static DEFINE_STATIC_KEY_FALSE(fgraph_do_direct); +#else static DEFINE_STATIC_KEY_TRUE(fgraph_do_direct); +#endif /** * ftrace_graph_stop - set to permanently disable function graph tracing @@ -843,7 +847,7 @@ __ftrace_return_to_handler(struct ftrace_regs *fregs, unsigned long frame_pointe bitmap = get_bitmap_bits(current, offset); #ifdef CONFIG_HAVE_STATIC_CALL - if (static_branch_likely(&fgraph_do_direct)) { + if (!FGRAPH_NO_DIRECT && static_branch_likely(&fgraph_do_direct)) { if (test_bit(fgraph_direct_gops->idx, &bitmap)) static_call(fgraph_retfunc)(&trace, fgraph_direct_gops, fregs); } else @@ -1285,6 +1289,9 @@ static void ftrace_graph_enable_direct(bool enable_branch, struct fgraph_ops *go trace_func_graph_ret_t retfunc = NULL; int i; + if (FGRAPH_NO_DIRECT) + return; + if (gops) { func = gops->entryfunc; retfunc = gops->retfunc; @@ -1308,6 +1315,9 @@ static void ftrace_graph_enable_direct(bool enable_branch, struct fgraph_ops *go static void ftrace_graph_disable_direct(bool disable_branch) { + if (FGRAPH_NO_DIRECT) + return; + if (disable_branch) static_branch_disable(&fgraph_do_direct); static_call_update(fgraph_func, ftrace_graph_entry_stub); -- 2.51.0[PATCH 6.19 837/844] fgraph: Do not call handlers direct when not using ftrace_opsSasha Levin undefinedlinux-kernel@vger.kernel.org, stable@vger.kernel.org undefined undefined undefined undefined undefined undefined