* [PATCH v2] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS
@ 2025-10-31 2:40 Menglong Dong
2025-11-01 18:20 ` kernel test robot
2025-11-03 3:16 ` Masami Hiramatsu
0 siblings, 2 replies; 4+ messages in thread
From: Menglong Dong @ 2025-10-31 2:40 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>
---
v2:
- remove the definition of FPROBE_USE_FTRACE
---
kernel/trace/fprobe.c | 30 +++++++++++++++++++-----------
1 file changed, 19 insertions(+), 11 deletions(-)
diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
index ecd623eef68b..742ad5a61d46 100644
--- a/kernel/trace/fprobe.c
+++ b/kernel/trace/fprobe.c
@@ -44,6 +44,7 @@
static struct hlist_head fprobe_table[FPROBE_TABLE_SIZE];
static struct rhltable fprobe_ip_table;
static DEFINE_MUTEX(fprobe_mutex);
+static struct fgraph_ops fprobe_graph_ops;
static u32 fprobe_node_hashfn(const void *data, u32 len, u32 seed)
{
@@ -254,7 +255,7 @@ 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)
/* 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 +296,7 @@ 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;
@@ -335,6 +336,13 @@ static bool fprobe_is_ftrace(struct fprobe *fp)
{
return !fp->exit_handler;
}
+
+static void fprobe_set_ips(unsigned long *ips, unsigned int cnt, int remove,
+ int reset)
+{
+ ftrace_set_filter_ips(&fprobe_graph_ops.ops, ips, cnt, remove, reset);
+ ftrace_set_filter_ips(&fprobe_ftrace_ops, ips, cnt, remove, reset);
+}
#else
static int fprobe_ftrace_add_ips(unsigned long *addrs, int num)
{
@@ -349,7 +357,13 @@ static bool fprobe_is_ftrace(struct fprobe *fp)
{
return false;
}
-#endif
+
+static void fprobe_set_ips(unsigned long *ips, unsigned int cnt, int remove,
+ int reset)
+{
+ ftrace_set_filter_ips(&fprobe_graph_ops.ops, ips, cnt, remove, reset);
+}
+#endif /* !CONFIG_DYNAMIC_FTRACE_WITH_ARGS && !CONFIG_DYNAMIC_FTRACE_WITH_REGS */
/* fgraph_ops callback, this processes fprobes which have exit_handler. */
static int fprobe_fgraph_entry(struct ftrace_graph_ent *trace, struct fgraph_ops *gops,
@@ -596,14 +610,8 @@ static int fprobe_module_callback(struct notifier_block *nb,
} while (node == ERR_PTR(-EAGAIN));
rhashtable_walk_exit(&iter);
- if (alist.index > 0) {
- ftrace_set_filter_ips(&fprobe_graph_ops.ops,
- alist.addrs, alist.index, 1, 0);
-#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
- ftrace_set_filter_ips(&fprobe_ftrace_ops,
- alist.addrs, alist.index, 1, 0);
-#endif
- }
+ if (alist.index > 0)
+ fprobe_set_ips(alist.addrs, alist.index, 1, 0);
mutex_unlock(&fprobe_mutex);
kfree(alist.addrs);
--
2.51.2
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v2] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS
2025-10-31 2:40 [PATCH v2] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS Menglong Dong
@ 2025-11-01 18:20 ` kernel test robot
2025-11-03 3:16 ` Masami Hiramatsu
1 sibling, 0 replies; 4+ messages in thread
From: kernel test robot @ 2025-11-01 18:20 UTC (permalink / raw)
To: Menglong Dong, mhiramat
Cc: oe-kbuild-all, rostedt, jolsa, mathieu.desnoyers, jiang.biao,
linux-kernel, linux-trace-kernel
Hi Menglong,
kernel test robot noticed the following build warnings:
[auto build test WARNING on trace/for-next]
[also build test WARNING on next-20251031]
[cannot apply to linus/master v6.18-rc3]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Menglong-Dong/tracing-fprobe-use-ftrace-if-CONFIG_DYNAMIC_FTRACE_WITH_ARGS/20251031-104301
base: https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace for-next
patch link: https://lore.kernel.org/r/20251031024038.19176-1-dongml2%40chinatelecom.cn
patch subject: [PATCH v2] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS
config: loongarch-randconfig-002-20251102 (https://download.01.org/0day-ci/archive/20251102/202511020220.bv169Bd9-lkp@intel.com/config)
compiler: loongarch64-linux-gcc (GCC) 15.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251102/202511020220.bv169Bd9-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202511020220.bv169Bd9-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> kernel/trace/fprobe.c:340:13: warning: 'fprobe_set_ips' defined but not used [-Wunused-function]
340 | static void fprobe_set_ips(unsigned long *ips, unsigned int cnt, int remove,
| ^~~~~~~~~~~~~~
vim +/fprobe_set_ips +340 kernel/trace/fprobe.c
339
> 340 static void fprobe_set_ips(unsigned long *ips, unsigned int cnt, int remove,
341 int reset)
342 {
343 ftrace_set_filter_ips(&fprobe_graph_ops.ops, ips, cnt, remove, reset);
344 ftrace_set_filter_ips(&fprobe_ftrace_ops, ips, cnt, remove, reset);
345 }
346 #else
347 static int fprobe_ftrace_add_ips(unsigned long *addrs, int num)
348 {
349 return -ENOENT;
350 }
351
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v2] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS
2025-10-31 2:40 [PATCH v2] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS Menglong Dong
2025-11-01 18:20 ` kernel test robot
@ 2025-11-03 3:16 ` Masami Hiramatsu
2025-11-03 6:17 ` Menglong Dong
1 sibling, 1 reply; 4+ messages in thread
From: Masami Hiramatsu @ 2025-11-03 3:16 UTC (permalink / raw)
To: Menglong Dong
Cc: rostedt, jolsa, mathieu.desnoyers, jiang.biao, linux-kernel,
linux-trace-kernel
On Fri, 31 Oct 2025 10:40:38 +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>
> ---
> v2:
> - remove the definition of FPROBE_USE_FTRACE
> ---
> kernel/trace/fprobe.c | 30 +++++++++++++++++++-----------
> 1 file changed, 19 insertions(+), 11 deletions(-)
>
> diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
> index ecd623eef68b..742ad5a61d46 100644
> --- a/kernel/trace/fprobe.c
> +++ b/kernel/trace/fprobe.c
> @@ -44,6 +44,7 @@
> static struct hlist_head fprobe_table[FPROBE_TABLE_SIZE];
> static struct rhltable fprobe_ip_table;
> static DEFINE_MUTEX(fprobe_mutex);
> +static struct fgraph_ops fprobe_graph_ops;
>
> static u32 fprobe_node_hashfn(const void *data, u32 len, u32 seed)
> {
> @@ -254,7 +255,7 @@ 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)
> /* 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 +296,7 @@ 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;
>
> @@ -335,6 +336,13 @@ static bool fprobe_is_ftrace(struct fprobe *fp)
> {
> return !fp->exit_handler;
> }
> +
Ah, the new function depends on MODULES.
#ifdef CONFIG_MODULES
> +static void fprobe_set_ips(unsigned long *ips, unsigned int cnt, int remove,
> + int reset)
> +{
> + ftrace_set_filter_ips(&fprobe_graph_ops.ops, ips, cnt, remove, reset);
> + ftrace_set_filter_ips(&fprobe_ftrace_ops, ips, cnt, remove, reset);
> +}
#endif /* CONFIG_MODULES */
> #else
#ifdef CONFIG_MODULES
> static int fprobe_ftrace_add_ips(unsigned long *addrs, int num)
> {
> @@ -349,7 +357,13 @@ static bool fprobe_is_ftrace(struct fprobe *fp)
> {
> return false;
> }
#endif /* CONFIG_MODULES */
are needed.
Thank you,
> -#endif
> +
> +static void fprobe_set_ips(unsigned long *ips, unsigned int cnt, int remove,
> + int reset)
> +{
> + ftrace_set_filter_ips(&fprobe_graph_ops.ops, ips, cnt, remove, reset);
> +}
> +#endif /* !CONFIG_DYNAMIC_FTRACE_WITH_ARGS && !CONFIG_DYNAMIC_FTRACE_WITH_REGS */
>
> /* fgraph_ops callback, this processes fprobes which have exit_handler. */
> static int fprobe_fgraph_entry(struct ftrace_graph_ent *trace, struct fgraph_ops *gops,
> @@ -596,14 +610,8 @@ static int fprobe_module_callback(struct notifier_block *nb,
> } while (node == ERR_PTR(-EAGAIN));
> rhashtable_walk_exit(&iter);
>
> - if (alist.index > 0) {
> - ftrace_set_filter_ips(&fprobe_graph_ops.ops,
> - alist.addrs, alist.index, 1, 0);
> -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
> - ftrace_set_filter_ips(&fprobe_ftrace_ops,
> - alist.addrs, alist.index, 1, 0);
> -#endif
> - }
> + if (alist.index > 0)
> + fprobe_set_ips(alist.addrs, alist.index, 1, 0);
> mutex_unlock(&fprobe_mutex);
>
> kfree(alist.addrs);
> --
> 2.51.2
>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH v2] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS
2025-11-03 3:16 ` Masami Hiramatsu
@ 2025-11-03 6:17 ` Menglong Dong
0 siblings, 0 replies; 4+ messages in thread
From: Menglong Dong @ 2025-11-03 6:17 UTC (permalink / raw)
To: Menglong Dong, Masami Hiramatsu
Cc: rostedt, jolsa, mathieu.desnoyers, jiang.biao, linux-kernel,
linux-trace-kernel
On 2025/11/3 11:16, Masami Hiramatsu wrote:
> On Fri, 31 Oct 2025 10:40:38 +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>
> > ---
> > v2:
> > - remove the definition of FPROBE_USE_FTRACE
> > ---
> > kernel/trace/fprobe.c | 30 +++++++++++++++++++-----------
> > 1 file changed, 19 insertions(+), 11 deletions(-)
> >
> > diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c
> > index ecd623eef68b..742ad5a61d46 100644
> > --- a/kernel/trace/fprobe.c
> > +++ b/kernel/trace/fprobe.c
> > @@ -44,6 +44,7 @@
> > static struct hlist_head fprobe_table[FPROBE_TABLE_SIZE];
> > static struct rhltable fprobe_ip_table;
> > static DEFINE_MUTEX(fprobe_mutex);
> > +static struct fgraph_ops fprobe_graph_ops;
> >
> > static u32 fprobe_node_hashfn(const void *data, u32 len, u32 seed)
> > {
> > @@ -254,7 +255,7 @@ 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)
> > /* 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 +296,7 @@ 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;
> >
> > @@ -335,6 +336,13 @@ static bool fprobe_is_ftrace(struct fprobe *fp)
> > {
> > return !fp->exit_handler;
> > }
> > +
>
> Ah, the new function depends on MODULES.
>
> #ifdef CONFIG_MODULES
>
> > +static void fprobe_set_ips(unsigned long *ips, unsigned int cnt, int remove,
> > + int reset)
> > +{
> > + ftrace_set_filter_ips(&fprobe_graph_ops.ops, ips, cnt, remove, reset);
> > + ftrace_set_filter_ips(&fprobe_ftrace_ops, ips, cnt, remove, reset);
> > +}
>
> #endif /* CONFIG_MODULES */
Yeah, I saw the CI's build warning. I'll send a V3 to fix
this issue.
Thanks!
Menglong Dong
>
> > #else
>
> #ifdef CONFIG_MODULES
>
> > static int fprobe_ftrace_add_ips(unsigned long *addrs, int num)
> > {
> > @@ -349,7 +357,13 @@ static bool fprobe_is_ftrace(struct fprobe *fp)
> > {
> > return false;
> > }
>
> #endif /* CONFIG_MODULES */
>
> are needed.
>
> Thank you,
>
> > -#endif
> > +
> > +static void fprobe_set_ips(unsigned long *ips, unsigned int cnt, int remove,
> > + int reset)
> > +{
> > + ftrace_set_filter_ips(&fprobe_graph_ops.ops, ips, cnt, remove, reset);
> > +}
> > +#endif /* !CONFIG_DYNAMIC_FTRACE_WITH_ARGS && !CONFIG_DYNAMIC_FTRACE_WITH_REGS */
> >
> > /* fgraph_ops callback, this processes fprobes which have exit_handler. */
> > static int fprobe_fgraph_entry(struct ftrace_graph_ent *trace, struct fgraph_ops *gops,
> > @@ -596,14 +610,8 @@ static int fprobe_module_callback(struct notifier_block *nb,
> > } while (node == ERR_PTR(-EAGAIN));
> > rhashtable_walk_exit(&iter);
> >
> > - if (alist.index > 0) {
> > - ftrace_set_filter_ips(&fprobe_graph_ops.ops,
> > - alist.addrs, alist.index, 1, 0);
> > -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
> > - ftrace_set_filter_ips(&fprobe_ftrace_ops,
> > - alist.addrs, alist.index, 1, 0);
> > -#endif
> > - }
> > + if (alist.index > 0)
> > + fprobe_set_ips(alist.addrs, alist.index, 1, 0);
> > mutex_unlock(&fprobe_mutex);
> >
> > kfree(alist.addrs);
>
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2025-11-03 6:18 UTC | newest]
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2025-10-31 2:40 [PATCH v2] tracing: fprobe: use ftrace if CONFIG_DYNAMIC_FTRACE_WITH_ARGS Menglong Dong
2025-11-01 18:20 ` kernel test robot
2025-11-03 3:16 ` Masami Hiramatsu
2025-11-03 6:17 ` Menglong Dong
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