On 2025/11/3 11:16, Masami Hiramatsu wrote:
> On Fri, 31 Oct 2025 10:40:38 +0800
> Menglong Dong <[email protected]> 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 <[email protected]>
> > ---
> > 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);
>
>
>
