* [PATCH] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS @ 2025-10-29 2:15 Menglong Dong 2025-10-29 14:00 ` Steven Rostedt 2025-10-30 0:40 ` Masami Hiramatsu 0 siblings, 2 replies; 6+ messages in thread From: Menglong Dong @ 2025-10-29 2:15 UTC (permalink / raw) To: mhiramat Cc: rostedt, jolsa, mathieu.desnoyers, jiang.biao, linux-kernel, linux-trace-kernel For now, we will use ftrace for the fprobe if fp->exit_handler not exists and CONFIG_DYNAMIC_FTRACE_WITH_REGS is enabled. However, CONFIG_DYNAMIC_FTRACE_WITH_REGS is not supported by some arch, such as arm. What we need in the fprobe is the function arguments, so we can use ftrace for fprobe if CONFIG_DYNAMIC_FTRACE_WITH_ARGS is enabled. Therefore, use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_REGS or CONFIG_DYNAMIC_FTRACE_WITH_ARGS enabled. Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn> --- kernel/trace/fprobe.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c index ecd623eef68b..9fad0569f521 100644 --- a/kernel/trace/fprobe.c +++ b/kernel/trace/fprobe.c @@ -254,7 +254,11 @@ static inline int __fprobe_kprobe_handler(unsigned long ip, unsigned long parent return ret; } -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS +#if defined(CONFIG_DYNAMIC_FTRACE_WITH_ARGS) || defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) +#define FPROBE_USE_FTRACE +#endif + +#ifdef FPROBE_USE_FTRACE /* ftrace_ops callback, this processes fprobes which have only entry_handler. */ static void fprobe_ftrace_entry(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *ops, struct ftrace_regs *fregs) @@ -295,7 +299,7 @@ NOKPROBE_SYMBOL(fprobe_ftrace_entry); static struct ftrace_ops fprobe_ftrace_ops = { .func = fprobe_ftrace_entry, - .flags = FTRACE_OPS_FL_SAVE_REGS, + .flags = FTRACE_OPS_FL_SAVE_ARGS, }; static int fprobe_ftrace_active; @@ -349,7 +353,7 @@ static bool fprobe_is_ftrace(struct fprobe *fp) { return false; } -#endif +#endif /* !FPROBE_USE_FTRACE */ /* fgraph_ops callback, this processes fprobes which have exit_handler. */ static int fprobe_fgraph_entry(struct ftrace_graph_ent *trace, struct fgraph_ops *gops, @@ -599,7 +603,7 @@ static int fprobe_module_callback(struct notifier_block *nb, if (alist.index > 0) { ftrace_set_filter_ips(&fprobe_graph_ops.ops, alist.addrs, alist.index, 1, 0); -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS +#ifdef FPROBE_USE_FTRACE ftrace_set_filter_ips(&fprobe_ftrace_ops, alist.addrs, alist.index, 1, 0); #endif -- 2.51.1 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS 2025-10-29 2:15 [PATCH] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS Menglong Dong @ 2025-10-29 14:00 ` Steven Rostedt 2025-10-29 14:09 ` Menglong Dong 2025-10-30 0:40 ` Masami Hiramatsu 1 sibling, 1 reply; 6+ messages in thread From: Steven Rostedt @ 2025-10-29 14:00 UTC (permalink / raw) To: Menglong Dong Cc: mhiramat, jolsa, mathieu.desnoyers, jiang.biao, linux-kernel, linux-trace-kernel On Wed, 29 Oct 2025 10:15:14 +0800 Menglong Dong <menglong8.dong@gmail.com> wrote: > -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS > +#if defined(CONFIG_DYNAMIC_FTRACE_WITH_ARGS) || defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) > +#define FPROBE_USE_FTRACE > +#endif > + > +#ifdef FPROBE_USE_FTRACE > /* ftrace_ops callback, this processes fprobes which have only entry_handler. */ > static void fprobe_ftrace_entry(unsigned long ip, unsigned long parent_ip, > struct ftrace_ops *ops, struct ftrace_regs *fregs) > @@ -295,7 +299,7 @@ NOKPROBE_SYMBOL(fprobe_ftrace_entry); > > static struct ftrace_ops fprobe_ftrace_ops = { > .func = fprobe_ftrace_entry, > - .flags = FTRACE_OPS_FL_SAVE_REGS, > + .flags = FTRACE_OPS_FL_SAVE_ARGS, If an arch defines DYNAMIC_FTRACE_WITH_REGS but not DYNAMIC_FTRACE_WITH_ARGS, then this will fail to build. > }; > static int fprobe_ftrace_active; > Perhaps do: #ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS # define FPROBE_FTRACE_TYPE FTRACE_OPS_FL_SAVE_ARGS #elif defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) # define FPROBE_FTRACE_TYPE FTRACE_OPS_FL_SAVE_REGS, #endif #ifdef FPROBE_FTRACE_TYPE [..] static struct ftrace_ops fprobe_ftrace_ops = { .func = fprobe_ftrace_entry, .flags = FTRACE_FTRACE_TYPE, ? -- Steve ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS 2025-10-29 14:00 ` Steven Rostedt @ 2025-10-29 14:09 ` Menglong Dong 2025-10-29 14:23 ` Steven Rostedt 0 siblings, 1 reply; 6+ messages in thread From: Menglong Dong @ 2025-10-29 14:09 UTC (permalink / raw) To: Steven Rostedt Cc: mhiramat, jolsa, mathieu.desnoyers, jiang.biao, linux-kernel, linux-trace-kernel On Wed, Oct 29, 2025 at 10:00 PM Steven Rostedt <rostedt@goodmis.org> wrote: > > On Wed, 29 Oct 2025 10:15:14 +0800 > Menglong Dong <menglong8.dong@gmail.com> wrote: > > > -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS > > +#if defined(CONFIG_DYNAMIC_FTRACE_WITH_ARGS) || defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) > > +#define FPROBE_USE_FTRACE > > +#endif > > + > > +#ifdef FPROBE_USE_FTRACE > > /* ftrace_ops callback, this processes fprobes which have only entry_handler. */ > > static void fprobe_ftrace_entry(unsigned long ip, unsigned long parent_ip, > > struct ftrace_ops *ops, struct ftrace_regs *fregs) > > @@ -295,7 +299,7 @@ NOKPROBE_SYMBOL(fprobe_ftrace_entry); > > > > static struct ftrace_ops fprobe_ftrace_ops = { > > .func = fprobe_ftrace_entry, > > - .flags = FTRACE_OPS_FL_SAVE_REGS, > > + .flags = FTRACE_OPS_FL_SAVE_ARGS, > > If an arch defines DYNAMIC_FTRACE_WITH_REGS but not > DYNAMIC_FTRACE_WITH_ARGS, then this will fail to build. Hi, it won't fail here, as FTRACE_OPS_FL_SAVE_ARGS has following definition: #ifndef CONFIG_DYNAMIC_FTRACE_WITH_ARGS #define FTRACE_OPS_FL_SAVE_ARGS FTRACE_OPS_FL_SAVE_REGS #else #define FTRACE_OPS_FL_SAVE_ARGS 0 #endif Which means it will fallback to FTRACE_OPS_FL_SAVE_REGS if CONFIG_DYNAMIC_FTRACE_WITH_ARGS not defined. I have commit a PR to the bpf CI, and all testings passed and no building error happens: https://github.com/kernel-patches/bpf/pull/10110 Thanks! Menglong Dong > > > }; > > static int fprobe_ftrace_active; > > > > Perhaps do: > > #ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS > # define FPROBE_FTRACE_TYPE FTRACE_OPS_FL_SAVE_ARGS > #elif defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) > # define FPROBE_FTRACE_TYPE FTRACE_OPS_FL_SAVE_REGS, > #endif > > #ifdef FPROBE_FTRACE_TYPE > [..] > static struct ftrace_ops fprobe_ftrace_ops = { > .func = fprobe_ftrace_entry, > .flags = FTRACE_FTRACE_TYPE, > > > ? > > -- Steve ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS 2025-10-29 14:09 ` Menglong Dong @ 2025-10-29 14:23 ` Steven Rostedt 0 siblings, 0 replies; 6+ messages in thread From: Steven Rostedt @ 2025-10-29 14:23 UTC (permalink / raw) To: Menglong Dong Cc: mhiramat, jolsa, mathieu.desnoyers, jiang.biao, linux-kernel, linux-trace-kernel On Wed, 29 Oct 2025 22:09:40 +0800 Menglong Dong <menglong8.dong@gmail.com> wrote: > Hi, it won't fail here, as FTRACE_OPS_FL_SAVE_ARGS has > following definition: > > #ifndef CONFIG_DYNAMIC_FTRACE_WITH_ARGS > #define FTRACE_OPS_FL_SAVE_ARGS FTRACE_OPS_FL_SAVE_REGS > #else > #define FTRACE_OPS_FL_SAVE_ARGS 0 > #endif Bah, I should have known that, as I think I requested it :-p [ chalks this up for a senior moment! ] > > Which means it will fallback to FTRACE_OPS_FL_SAVE_REGS if > CONFIG_DYNAMIC_FTRACE_WITH_ARGS not defined. > > I have commit a PR to the bpf CI, and all testings passed and no > building error happens: > https://github.com/kernel-patches/bpf/pull/10110 OK, thanks, -- Steve ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS 2025-10-29 2:15 [PATCH] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS Menglong Dong 2025-10-29 14:00 ` Steven Rostedt @ 2025-10-30 0:40 ` Masami Hiramatsu 2025-10-30 2:43 ` Menglong Dong 1 sibling, 1 reply; 6+ messages in thread From: Masami Hiramatsu @ 2025-10-30 0:40 UTC (permalink / raw) To: Menglong Dong Cc: rostedt, jolsa, mathieu.desnoyers, jiang.biao, linux-kernel, linux-trace-kernel On Wed, 29 Oct 2025 10:15:14 +0800 Menglong Dong <menglong8.dong@gmail.com> wrote: > For now, we will use ftrace for the fprobe if fp->exit_handler not exists > and CONFIG_DYNAMIC_FTRACE_WITH_REGS is enabled. > > However, CONFIG_DYNAMIC_FTRACE_WITH_REGS is not supported by some arch, > such as arm. What we need in the fprobe is the function arguments, so we > can use ftrace for fprobe if CONFIG_DYNAMIC_FTRACE_WITH_ARGS is enabled. > > Therefore, use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_REGS or > CONFIG_DYNAMIC_FTRACE_WITH_ARGS enabled. > > Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn> > --- > kernel/trace/fprobe.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c > index ecd623eef68b..9fad0569f521 100644 > --- a/kernel/trace/fprobe.c > +++ b/kernel/trace/fprobe.c > @@ -254,7 +254,11 @@ static inline int __fprobe_kprobe_handler(unsigned long ip, unsigned long parent > return ret; > } > > -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS > +#if defined(CONFIG_DYNAMIC_FTRACE_WITH_ARGS) || defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) > +#define FPROBE_USE_FTRACE > +#endif > + > +#ifdef FPROBE_USE_FTRACE > /* ftrace_ops callback, this processes fprobes which have only entry_handler. */ > static void fprobe_ftrace_entry(unsigned long ip, unsigned long parent_ip, > struct ftrace_ops *ops, struct ftrace_regs *fregs) > @@ -295,7 +299,7 @@ NOKPROBE_SYMBOL(fprobe_ftrace_entry); > > static struct ftrace_ops fprobe_ftrace_ops = { > .func = fprobe_ftrace_entry, > - .flags = FTRACE_OPS_FL_SAVE_REGS, > + .flags = FTRACE_OPS_FL_SAVE_ARGS, > }; > static int fprobe_ftrace_active; > > @@ -349,7 +353,7 @@ static bool fprobe_is_ftrace(struct fprobe *fp) > { > return false; > } > -#endif > +#endif /* !FPROBE_USE_FTRACE */ > > /* fgraph_ops callback, this processes fprobes which have exit_handler. */ > static int fprobe_fgraph_entry(struct ftrace_graph_ent *trace, struct fgraph_ops *gops, > @@ -599,7 +603,7 @@ static int fprobe_module_callback(struct notifier_block *nb, > if (alist.index > 0) { > ftrace_set_filter_ips(&fprobe_graph_ops.ops, > alist.addrs, alist.index, 1, 0); > -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS > +#ifdef FPROBE_USE_FTRACE > ftrace_set_filter_ips(&fprobe_ftrace_ops, > alist.addrs, alist.index, 1, 0); > #endif Instead of introducing FPROBE_USE_FTRACE, I think it is better to add another wrapper to be called here. #if defined(CONFIG_DYNAMIC_FTRACE_WITH_ARGS) || defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) static void fprobe_set_ips(unsigned long *ips, unsigned int cnt, int remove, int reset) { ftrace_set_filter_ips(&fprobe_graph_ops.ops, alist.addrs, alist.index, 1, 0); ftrace_set_filter_ips(&fprobe_ftrace_ops, alist.addrs, alist.index, 1, 0); } ... #else static void fprobe_set_ips(unsigned long *ips, unsigned int cnt, int remove, int reset) { ftrace_set_filter_ips(&fprobe_graph_ops.ops, alist.addrs, alist.index, 1, 0); } #endif Thank you, -- Masami Hiramatsu (Google) <mhiramat@kernel.org> ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS 2025-10-30 0:40 ` Masami Hiramatsu @ 2025-10-30 2:43 ` Menglong Dong 0 siblings, 0 replies; 6+ messages in thread From: Menglong Dong @ 2025-10-30 2:43 UTC (permalink / raw) To: Menglong Dong, Masami Hiramatsu Cc: rostedt, jolsa, mathieu.desnoyers, jiang.biao, linux-kernel, linux-trace-kernel On 2025/10/30 08:40, Masami Hiramatsu wrote: > On Wed, 29 Oct 2025 10:15:14 +0800 > Menglong Dong <menglong8.dong@gmail.com> wrote: > > > For now, we will use ftrace for the fprobe if fp->exit_handler not exists > > and CONFIG_DYNAMIC_FTRACE_WITH_REGS is enabled. > > > > However, CONFIG_DYNAMIC_FTRACE_WITH_REGS is not supported by some arch, > > such as arm. What we need in the fprobe is the function arguments, so we > > can use ftrace for fprobe if CONFIG_DYNAMIC_FTRACE_WITH_ARGS is enabled. > > > > Therefore, use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_REGS or > > CONFIG_DYNAMIC_FTRACE_WITH_ARGS enabled. > > > > Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn> > > --- > > kernel/trace/fprobe.c | 12 ++++++++---- > > 1 file changed, 8 insertions(+), 4 deletions(-) > > > > diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c > > index ecd623eef68b..9fad0569f521 100644 > > --- a/kernel/trace/fprobe.c > > +++ b/kernel/trace/fprobe.c > > @@ -254,7 +254,11 @@ static inline int __fprobe_kprobe_handler(unsigned long ip, unsigned long parent > > return ret; > > } > > > > -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS > > +#if defined(CONFIG_DYNAMIC_FTRACE_WITH_ARGS) || defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) > > +#define FPROBE_USE_FTRACE > > +#endif > > + > > +#ifdef FPROBE_USE_FTRACE > > /* ftrace_ops callback, this processes fprobes which have only entry_handler. */ > > static void fprobe_ftrace_entry(unsigned long ip, unsigned long parent_ip, > > struct ftrace_ops *ops, struct ftrace_regs *fregs) > > @@ -295,7 +299,7 @@ NOKPROBE_SYMBOL(fprobe_ftrace_entry); > > > > static struct ftrace_ops fprobe_ftrace_ops = { > > .func = fprobe_ftrace_entry, > > - .flags = FTRACE_OPS_FL_SAVE_REGS, > > + .flags = FTRACE_OPS_FL_SAVE_ARGS, > > }; > > static int fprobe_ftrace_active; > > > > @@ -349,7 +353,7 @@ static bool fprobe_is_ftrace(struct fprobe *fp) > > { > > return false; > > } > > -#endif > > +#endif /* !FPROBE_USE_FTRACE */ > > > > /* fgraph_ops callback, this processes fprobes which have exit_handler. */ > > static int fprobe_fgraph_entry(struct ftrace_graph_ent *trace, struct fgraph_ops *gops, > > @@ -599,7 +603,7 @@ static int fprobe_module_callback(struct notifier_block *nb, > > if (alist.index > 0) { > > ftrace_set_filter_ips(&fprobe_graph_ops.ops, > > alist.addrs, alist.index, 1, 0); > > -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS > > +#ifdef FPROBE_USE_FTRACE > > ftrace_set_filter_ips(&fprobe_ftrace_ops, > > alist.addrs, alist.index, 1, 0); > > #endif > > Instead of introducing FPROBE_USE_FTRACE, I think it is better to add another > wrapper to be called here. Sounds better! I'll modify it in the next version. Thanks! Menglong Dong > > #if defined(CONFIG_DYNAMIC_FTRACE_WITH_ARGS) || defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS) > > static void fprobe_set_ips(unsigned long *ips, unsigned int cnt, int remove, int reset) > { > ftrace_set_filter_ips(&fprobe_graph_ops.ops, > alist.addrs, alist.index, 1, 0); > ftrace_set_filter_ips(&fprobe_ftrace_ops, > alist.addrs, alist.index, 1, 0); > } > ... > #else > static void fprobe_set_ips(unsigned long *ips, unsigned int cnt, int remove, int reset) > { > ftrace_set_filter_ips(&fprobe_graph_ops.ops, > alist.addrs, alist.index, 1, 0); > } > #endif > > Thank you, > > ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2025-10-30 2:43 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2025-10-29 2:15 [PATCH] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS Menglong Dong 2025-10-29 14:00 ` Steven Rostedt 2025-10-29 14:09 ` Menglong Dong 2025-10-29 14:23 ` Steven Rostedt 2025-10-30 0:40 ` Masami Hiramatsu 2025-10-30 2:43 ` Menglong Dong
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