[PATCH v5 v5 0/3] tracing/fprobe: Support comma-separated symbols and :entry/:exit

[PATCH v5 v5 0/3] tracing/fprobe: Support comma-separated symbols and :entry/:exit

[Seokwoo Chung (Ryan)]

This series extends fprobe dynamic events to accept a comma-separated list of
symbols and explicit/suffixes.

Currently, fprobe only supports a single symbol (or wildcard) per event. This
series allow users to specify a comma-separated list of symbols, including
exclusions, and to select entry/exit explicitly using /

Examples:
- f:[GRP/][EVENT] func1,func2,func3
- f:[GRP/][EVENT] func1,!func2,func3 (exclude with '!')

Logic changes:
- Refactor parsing logic into parse_fprobe_spec()
- Support comma-separated lists and '!' exclusions
- Add / suffixes for explicit entry/exit selection
- Preserve legacy single-symbol behavior (single symbols still accept %return)
- Disable BTF-based signature lookup when list/wildcard is used, since one
  function signature cannot apply to multiple functions
- Reject mixed legacy/new syntax where applicable (e.g. list + %return)
- Update tracefs/README and fprobe documentation
- Add ftrace selftests covering accepted list syntax cases

*Patch order is adjusted: code first, then docs, then selftest

Changes in v5:
- Reordered patches (code->docs->selftests) as suggested
- Addressed review feedback on README help text to show both legacy and list
  syntaxes
- Added missing traceprobe error IDs used by the new validation and fixed
  parsing/bracing issues found by automated builds
- Removed the dedicated list_mode field and infer list behavior from presence of
  filter/nofilter and keep struct trace_probe as the last member
- Link to v4: https://lore.kernel.org/linux-trace-kernel/20251127151218.4763b25c751bb2aac4b1ee36@kernel.org/

I am not fully confident the runtime testing coverage that I did is sufficient
across configs/architectures, so additional verification would be appreciated.

Best regards,
Ryan Chung


Seokwoo Chung (Ryan) (3):
  docs: tracing/fprobe: Document list filters and :entry/:exit
  tracing/fprobe: Support comma-separated symbols and :entry/:exit
  selftests/ftrace: Add accept cases for fprobe list syntax

 Documentation/trace/fprobetrace.rst           |  17 +-
 kernel/trace/trace.c                          |   3 +-
 kernel/trace/trace_fprobe.c                   | 209 ++++++++++++++----
 .../ftrace/test.d/dynevent/fprobe_list.tc     |  92 ++++++++
 4 files changed, 269 insertions(+), 52 deletions(-)
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/fprobe_list.tc

-- 
2.43.0

[PATCH v5 v5 1/3] docs: tracing/fprobe: Document list filters and :entry/:exit

[Seokwoo Chung (Ryan)]

Update fprobe event documentation to describe comma-separated symbol lists,
exclusions, and explicit suffixes.

Signed-off-by: Seokwoo Chung (Ryan) <seokwoo.chung130@gmail.com>
---
 Documentation/trace/fprobetrace.rst | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/Documentation/trace/fprobetrace.rst b/Documentation/trace/fprobetrace.rst
index b4c2ca3d02c1..bbcfd57f0005 100644
--- a/Documentation/trace/fprobetrace.rst
+++ b/Documentation/trace/fprobetrace.rst
@@ -25,14 +25,18 @@ Synopsis of fprobe-events
 -------------------------
 ::
 
-  f[:[GRP1/][EVENT1]] SYM [FETCHARGS]                       : Probe on function entry
-  f[MAXACTIVE][:[GRP1/][EVENT1]] SYM%return [FETCHARGS]     : Probe on function exit
+  f[:[GRP1/][EVENT1]] SYM[%return] [FETCHARGS]		    : Single function
+  f[:[GRP1/][EVENT1]] SYM[,[!]SYM[,...]][:entry|:exit] [FETCHARGS] :Multiple
+  function
   t[:[GRP2/][EVENT2]] TRACEPOINT [FETCHARGS]                : Probe on tracepoint
 
  GRP1           : Group name for fprobe. If omitted, use "fprobes" for it.
  GRP2           : Group name for tprobe. If omitted, use "tracepoints" for it.
  EVENT1         : Event name for fprobe. If omitted, the event name is
-                  "SYM__entry" or "SYM__exit".
+		  - For a single literal symbol, the event name is
+		    "SYM__entry" or "SYM__exit".
+		  - For a *list or any wildcard*, an explicit [GRP1/][EVENT1] is
+		    required; otherwise the parser rejects it.
  EVENT2         : Event name for tprobe. If omitted, the event name is
                   the same as "TRACEPOINT", but if the "TRACEPOINT" starts
                   with a digit character, "_TRACEPOINT" is used.
@@ -40,6 +44,13 @@ Synopsis of fprobe-events
                   can be probed simultaneously, or 0 for the default value
                   as defined in Documentation/trace/fprobe.rst
 
+ SYM		: Function name or comma-separated list of symbols.
+		  - SYM prefixed with "!" are exclusions.
+		  - ":entry" suffix means it probes entry of given symbols
+		    (default)
+		  - ":exit" suffix means it probes exit of given symbols.
+		  - "%return" suffix means it probes exit of SYM (single
+		    symbol).
  FETCHARGS      : Arguments. Each probe can have up to 128 args.
   ARG           : Fetch "ARG" function argument using BTF (only for function
                   entry or tracepoint.) (\*1)
-- 
2.43.0

Re: [PATCH v5 v5 1/3] docs: tracing/fprobe: Document list filters and :entry/:exit

[Steven Rostedt]

On Sat, 17 Jan 2026 20:18:13 -0500
"Seokwoo Chung (Ryan)" <seokwoo.chung130@gmail.com> wrote:

> Update fprobe event documentation to describe comma-separated symbol lists,
> exclusions, and explicit suffixes.

Usually, the documentation updates comes *after* the changes.

-- Steve

> 
> Signed-off-by: Seokwoo Chung (Ryan) <seokwoo.chung130@gmail.com>
> ---
>  Documentation/trace/fprobetrace.rst | 17 ++++++++++++++---
>  1 file changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/trace/fprobetrace.rst b/Documentation/trace/fprobetrace.rst
> index b4c2ca3d02c1..bbcfd57f0005 100644
> --- a/Documentation/trace/fprobetrace.rst
> +++ b/Documentation/trace/fprobetrace.rst
> @@ -25,14 +25,18 @@ Synopsis of fprobe-events
>  -------------------------
>  ::
>  
> -  f[:[GRP1/][EVENT1]] SYM [FETCHARGS]                       : Probe on function entry
> -  f[MAXACTIVE][:[GRP1/][EVENT1]] SYM%return [FETCHARGS]     : Probe on function exit
> +  f[:[GRP1/][EVENT1]] SYM[%return] [FETCHARGS]		    : Single function
> +  f[:[GRP1/][EVENT1]] SYM[,[!]SYM[,...]][:entry|:exit] [FETCHARGS] :Multiple
> +  function
>    t[:[GRP2/][EVENT2]] TRACEPOINT [FETCHARGS]                : Probe on tracepoint
>  
>   GRP1           : Group name for fprobe. If omitted, use "fprobes" for it.
>   GRP2           : Group name for tprobe. If omitted, use "tracepoints" for it.
>   EVENT1         : Event name for fprobe. If omitted, the event name is
> -                  "SYM__entry" or "SYM__exit".
> +		  - For a single literal symbol, the event name is
> +		    "SYM__entry" or "SYM__exit".
> +		  - For a *list or any wildcard*, an explicit [GRP1/][EVENT1] is
> +		    required; otherwise the parser rejects it.
>   EVENT2         : Event name for tprobe. If omitted, the event name is
>                    the same as "TRACEPOINT", but if the "TRACEPOINT" starts
>                    with a digit character, "_TRACEPOINT" is used.
> @@ -40,6 +44,13 @@ Synopsis of fprobe-events
>                    can be probed simultaneously, or 0 for the default value
>                    as defined in Documentation/trace/fprobe.rst
>  
> + SYM		: Function name or comma-separated list of symbols.
> +		  - SYM prefixed with "!" are exclusions.
> +		  - ":entry" suffix means it probes entry of given symbols
> +		    (default)
> +		  - ":exit" suffix means it probes exit of given symbols.
> +		  - "%return" suffix means it probes exit of SYM (single
> +		    symbol).
>   FETCHARGS      : Arguments. Each probe can have up to 128 args.
>    ARG           : Fetch "ARG" function argument using BTF (only for function
>                    entry or tracepoint.) (\*1)

Re: [PATCH v5 v5 1/3] docs: tracing/fprobe: Document list filters and :entry/:exit

[Seokwoo Chung]

On Tue, Jan 20, 2026 at 03:53:40PM -0500, Steven Rostedt wrote:
> On Sat, 17 Jan 2026 20:18:13 -0500
> "Seokwoo Chung (Ryan)" <seokwoo.chung130@gmail.com> wrote:
> 
> > Update fprobe event documentation to describe comma-separated symbol lists,
> > exclusions, and explicit suffixes.
> 
> Usually, the documentation updates comes *after* the changes.
> 
> -- Steve
> 
Thanks for the comment. As you noticed, I sent another patch since I forgot to
put log. That said, please let me know if you want me to continue on this
series. My apologies on the ordering. I noted after Masami mentioned but I
misordered when sending. Thank you.

Best regards,
Ryan Chung
> > 
> > Signed-off-by: Seokwoo Chung (Ryan) <seokwoo.chung130@gmail.com>
> > ---
> >  Documentation/trace/fprobetrace.rst | 17 ++++++++++++++---
> >  1 file changed, 14 insertions(+), 3 deletions(-)
> > 
> > diff --git a/Documentation/trace/fprobetrace.rst b/Documentation/trace/fprobetrace.rst
> > index b4c2ca3d02c1..bbcfd57f0005 100644
> > --- a/Documentation/trace/fprobetrace.rst
> > +++ b/Documentation/trace/fprobetrace.rst
> > @@ -25,14 +25,18 @@ Synopsis of fprobe-events
> >  -------------------------
> >  ::
> >  
> > -  f[:[GRP1/][EVENT1]] SYM [FETCHARGS]                       : Probe on function entry
> > -  f[MAXACTIVE][:[GRP1/][EVENT1]] SYM%return [FETCHARGS]     : Probe on function exit
> > +  f[:[GRP1/][EVENT1]] SYM[%return] [FETCHARGS]		    : Single function
> > +  f[:[GRP1/][EVENT1]] SYM[,[!]SYM[,...]][:entry|:exit] [FETCHARGS] :Multiple
> > +  function
> >    t[:[GRP2/][EVENT2]] TRACEPOINT [FETCHARGS]                : Probe on tracepoint
> >  
> >   GRP1           : Group name for fprobe. If omitted, use "fprobes" for it.
> >   GRP2           : Group name for tprobe. If omitted, use "tracepoints" for it.
> >   EVENT1         : Event name for fprobe. If omitted, the event name is
> > -                  "SYM__entry" or "SYM__exit".
> > +		  - For a single literal symbol, the event name is
> > +		    "SYM__entry" or "SYM__exit".
> > +		  - For a *list or any wildcard*, an explicit [GRP1/][EVENT1] is
> > +		    required; otherwise the parser rejects it.
> >   EVENT2         : Event name for tprobe. If omitted, the event name is
> >                    the same as "TRACEPOINT", but if the "TRACEPOINT" starts
> >                    with a digit character, "_TRACEPOINT" is used.
> > @@ -40,6 +44,13 @@ Synopsis of fprobe-events
> >                    can be probed simultaneously, or 0 for the default value
> >                    as defined in Documentation/trace/fprobe.rst
> >  
> > + SYM		: Function name or comma-separated list of symbols.
> > +		  - SYM prefixed with "!" are exclusions.
> > +		  - ":entry" suffix means it probes entry of given symbols
> > +		    (default)
> > +		  - ":exit" suffix means it probes exit of given symbols.
> > +		  - "%return" suffix means it probes exit of SYM (single
> > +		    symbol).
> >   FETCHARGS      : Arguments. Each probe can have up to 128 args.
> >    ARG           : Fetch "ARG" function argument using BTF (only for function
> >                    entry or tracepoint.) (\*1)
> 

Re: [PATCH v5 v5 1/3] docs: tracing/fprobe: Document list filters and :entry/:exit

[Masami Hiramatsu]

Hi Ryan,

On Sun, 25 Jan 2026 15:23:17 -0500
Seokwoo Chung <seokwoo.chung130@gmail.com> wrote:

> On Tue, Jan 20, 2026 at 03:53:40PM -0500, Steven Rostedt wrote:
> > On Sat, 17 Jan 2026 20:18:13 -0500
> > "Seokwoo Chung (Ryan)" <seokwoo.chung130@gmail.com> wrote:
> > 
> > > Update fprobe event documentation to describe comma-separated symbol lists,
> > > exclusions, and explicit suffixes.
> > 
> > Usually, the documentation updates comes *after* the changes.
> > 
> > -- Steve
> > 
> Thanks for the comment. As you noticed, I sent another patch since I forgot to
> put log. That said, please let me know if you want me to continue on this
> series. My apologies on the ordering. I noted after Masami mentioned but I
> misordered when sending. Thank you.

Sorry for replying so late,
Can you fix the kernel test robot's error? I think it is almost done.

Thank you,

> 
> Best regards,
> Ryan Chung
> > > 
> > > Signed-off-by: Seokwoo Chung (Ryan) <seokwoo.chung130@gmail.com>
> > > ---
> > >  Documentation/trace/fprobetrace.rst | 17 ++++++++++++++---
> > >  1 file changed, 14 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/Documentation/trace/fprobetrace.rst b/Documentation/trace/fprobetrace.rst
> > > index b4c2ca3d02c1..bbcfd57f0005 100644
> > > --- a/Documentation/trace/fprobetrace.rst
> > > +++ b/Documentation/trace/fprobetrace.rst
> > > @@ -25,14 +25,18 @@ Synopsis of fprobe-events
> > >  -------------------------
> > >  ::
> > >  
> > > -  f[:[GRP1/][EVENT1]] SYM [FETCHARGS]                       : Probe on function entry
> > > -  f[MAXACTIVE][:[GRP1/][EVENT1]] SYM%return [FETCHARGS]     : Probe on function exit
> > > +  f[:[GRP1/][EVENT1]] SYM[%return] [FETCHARGS]		    : Single function
> > > +  f[:[GRP1/][EVENT1]] SYM[,[!]SYM[,...]][:entry|:exit] [FETCHARGS] :Multiple
> > > +  function
> > >    t[:[GRP2/][EVENT2]] TRACEPOINT [FETCHARGS]                : Probe on tracepoint
> > >  
> > >   GRP1           : Group name for fprobe. If omitted, use "fprobes" for it.
> > >   GRP2           : Group name for tprobe. If omitted, use "tracepoints" for it.
> > >   EVENT1         : Event name for fprobe. If omitted, the event name is
> > > -                  "SYM__entry" or "SYM__exit".
> > > +		  - For a single literal symbol, the event name is
> > > +		    "SYM__entry" or "SYM__exit".
> > > +		  - For a *list or any wildcard*, an explicit [GRP1/][EVENT1] is
> > > +		    required; otherwise the parser rejects it.
> > >   EVENT2         : Event name for tprobe. If omitted, the event name is
> > >                    the same as "TRACEPOINT", but if the "TRACEPOINT" starts
> > >                    with a digit character, "_TRACEPOINT" is used.
> > > @@ -40,6 +44,13 @@ Synopsis of fprobe-events
> > >                    can be probed simultaneously, or 0 for the default value
> > >                    as defined in Documentation/trace/fprobe.rst
> > >  
> > > + SYM		: Function name or comma-separated list of symbols.
> > > +		  - SYM prefixed with "!" are exclusions.
> > > +		  - ":entry" suffix means it probes entry of given symbols
> > > +		    (default)
> > > +		  - ":exit" suffix means it probes exit of given symbols.
> > > +		  - "%return" suffix means it probes exit of SYM (single
> > > +		    symbol).
> > >   FETCHARGS      : Arguments. Each probe can have up to 128 args.
> > >    ARG           : Fetch "ARG" function argument using BTF (only for function
> > >                    entry or tracepoint.) (\*1)
> > 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

Re: [PATCH v5 v5 1/3] docs: tracing/fprobe: Document list filters and :entry/:exit

[Seokwoo Chung]

On Thu, Jan 29, 2026 at 09:35:08AM +0900, Masami Hiramatsu wrote:
> Hi Ryan,
> 
> On Sun, 25 Jan 2026 15:23:17 -0500
> Seokwoo Chung <seokwoo.chung130@gmail.com> wrote:
> 
> > On Tue, Jan 20, 2026 at 03:53:40PM -0500, Steven Rostedt wrote:
> > > On Sat, 17 Jan 2026 20:18:13 -0500
> > > "Seokwoo Chung (Ryan)" <seokwoo.chung130@gmail.com> wrote:
> > > 
> > > > Update fprobe event documentation to describe comma-separated symbol lists,
> > > > exclusions, and explicit suffixes.
> > > 
> > > Usually, the documentation updates comes *after* the changes.
> > > 
> > > -- Steve
> > > 
> > Thanks for the comment. As you noticed, I sent another patch since I forgot to
> > put log. That said, please let me know if you want me to continue on this
> > series. My apologies on the ordering. I noted after Masami mentioned but I
> > misordered when sending. Thank you.
> 
> Sorry for replying so late,
> Can you fix the kernel test robot's error? I think it is almost done.
> 
> Thank you,
> 
Hi. Thanks for the reply. I will fix and send the next version.


> > 
> > Best regards,
> > Ryan Chung
> > > > 
> > > > Signed-off-by: Seokwoo Chung (Ryan) <seokwoo.chung130@gmail.com>
> > > > ---
> > > >  Documentation/trace/fprobetrace.rst | 17 ++++++++++++++---
> > > >  1 file changed, 14 insertions(+), 3 deletions(-)
> > > > 
> > > > diff --git a/Documentation/trace/fprobetrace.rst b/Documentation/trace/fprobetrace.rst
> > > > index b4c2ca3d02c1..bbcfd57f0005 100644
> > > > --- a/Documentation/trace/fprobetrace.rst
> > > > +++ b/Documentation/trace/fprobetrace.rst
> > > > @@ -25,14 +25,18 @@ Synopsis of fprobe-events
> > > >  -------------------------
> > > >  ::
> > > >  
> > > > -  f[:[GRP1/][EVENT1]] SYM [FETCHARGS]                       : Probe on function entry
> > > > -  f[MAXACTIVE][:[GRP1/][EVENT1]] SYM%return [FETCHARGS]     : Probe on function exit
> > > > +  f[:[GRP1/][EVENT1]] SYM[%return] [FETCHARGS]		    : Single function
> > > > +  f[:[GRP1/][EVENT1]] SYM[,[!]SYM[,...]][:entry|:exit] [FETCHARGS] :Multiple
> > > > +  function
> > > >    t[:[GRP2/][EVENT2]] TRACEPOINT [FETCHARGS]                : Probe on tracepoint
> > > >  
> > > >   GRP1           : Group name for fprobe. If omitted, use "fprobes" for it.
> > > >   GRP2           : Group name for tprobe. If omitted, use "tracepoints" for it.
> > > >   EVENT1         : Event name for fprobe. If omitted, the event name is
> > > > -                  "SYM__entry" or "SYM__exit".
> > > > +		  - For a single literal symbol, the event name is
> > > > +		    "SYM__entry" or "SYM__exit".
> > > > +		  - For a *list or any wildcard*, an explicit [GRP1/][EVENT1] is
> > > > +		    required; otherwise the parser rejects it.
> > > >   EVENT2         : Event name for tprobe. If omitted, the event name is
> > > >                    the same as "TRACEPOINT", but if the "TRACEPOINT" starts
> > > >                    with a digit character, "_TRACEPOINT" is used.
> > > > @@ -40,6 +44,13 @@ Synopsis of fprobe-events
> > > >                    can be probed simultaneously, or 0 for the default value
> > > >                    as defined in Documentation/trace/fprobe.rst
> > > >  
> > > > + SYM		: Function name or comma-separated list of symbols.
> > > > +		  - SYM prefixed with "!" are exclusions.
> > > > +		  - ":entry" suffix means it probes entry of given symbols
> > > > +		    (default)
> > > > +		  - ":exit" suffix means it probes exit of given symbols.
> > > > +		  - "%return" suffix means it probes exit of SYM (single
> > > > +		    symbol).
> > > >   FETCHARGS      : Arguments. Each probe can have up to 128 args.
> > > >    ARG           : Fetch "ARG" function argument using BTF (only for function
> > > >                    entry or tracepoint.) (\*1)
> > > 
> 
> 
> -- 
> Masami Hiramatsu (Google) <mhiramat@kernel.org>

Best regards,
Ryan Chung

[PATCH v5 v5 2/3] tracing/fprobe: Support comma-separated symbols and :entry/:exit

[Seokwoo Chung (Ryan)]

- Update DEFINE_FREE to use standard __free()
- Extend fprobe to support multiple symbols per event. Add parsing logic for
  lists, ! exclusions, and explicit suffixes. Update tracefs/README to reflect
  the new syntax

Signed-off-by: Seokwoo Chung (Ryan) <seokwoo.chung130@gmail.com>
---
 kernel/trace/trace.c        |   3 +-
 kernel/trace/trace_fprobe.c | 209 +++++++++++++++++++++++++++---------
 2 files changed, 163 insertions(+), 49 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index baec63134ab6..10cdcc7b194e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5578,7 +5578,8 @@ static const char readme_msg[] =
 	"\t           r[maxactive][:[<group>/][<event>]] <place> [<args>]\n"
 #endif
 #ifdef CONFIG_FPROBE_EVENTS
-	"\t           f[:[<group>/][<event>]] <func-name>[%return] [<args>]\n"
+	"\t           f[:[<group>/][<event>]] <func-name>[:entry|:exit] [<args>]\n"
+	"\t		(single symbols still accept %return)\n"
 	"\t           t[:[<group>/][<event>]] <tracepoint> [<args>]\n"
 #endif
 #ifdef CONFIG_HIST_TRIGGERS
diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
index 262c0556e4af..5a2a41eea603 100644
--- a/kernel/trace/trace_fprobe.c
+++ b/kernel/trace/trace_fprobe.c
@@ -187,11 +187,14 @@ DEFINE_FREE(tuser_put, struct tracepoint_user *,
  */
 struct trace_fprobe {
 	struct dyn_event	devent;
+	char			*filter;
 	struct fprobe		fp;
+	bool			list_mode;
+	char			*nofilter;
 	const char		*symbol;
+	struct trace_probe	tp;
 	bool			tprobe;
 	struct tracepoint_user	*tuser;
-	struct trace_probe	tp;
 };
 
 static bool is_trace_fprobe(struct dyn_event *ev)
@@ -559,6 +562,8 @@ static void free_trace_fprobe(struct trace_fprobe *tf)
 		trace_probe_cleanup(&tf->tp);
 		if (tf->tuser)
 			tracepoint_user_put(tf->tuser);
+		kfree(tf->filter);
+		kfree(tf->nofilter);
 		kfree(tf->symbol);
 		kfree(tf);
 	}
@@ -838,7 +843,12 @@ static int __register_trace_fprobe(struct trace_fprobe *tf)
 	if (trace_fprobe_is_tracepoint(tf))
 		return __regsiter_tracepoint_fprobe(tf);
 
-	/* TODO: handle filter, nofilter or symbol list */
+	/* Registration path:
+	 * - list_mode: pass filter/nofilter
+	 * - single: pass symbol only (legacy)
+	 */
+	if (tf->list_mode)
+		return register_fprobe(&tf->fp, tf->filter, tf->nofilter);
 	return register_fprobe(&tf->fp, tf->symbol, NULL);
 }
 
@@ -1154,60 +1164,119 @@ static struct notifier_block tprobe_event_module_nb = {
 };
 #endif /* CONFIG_MODULES */
 
-static int parse_symbol_and_return(int argc, const char *argv[],
-				   char **symbol, bool *is_return,
-				   bool is_tracepoint)
+static bool has_wildcard(const char *s)
 {
-	char *tmp = strchr(argv[1], '%');
-	int i;
+	return s && (strchr(s, '*') || strchr(s, '?'));
+}
 
-	if (tmp) {
-		int len = tmp - argv[1];
+static int parse_fprobe_spec(const char *in, bool is_tracepoint,
+		char **base, bool *is_return, bool *list_mode,
+		char **filter, char **nofilter)
+{
+	char *work __free(kfree) = NULL;
+	char *b __free(kfree) = NULL;
+	char *f __free(kfree) = NULL;
+	char *nf __free(kfree) = NULL;
+	bool legacy_ret = false;
+	bool list = false;
+	const char *p;
+	int ret = 0;
 
-		if (!is_tracepoint && !strcmp(tmp, "%return")) {
-			*is_return = true;
-		} else {
-			trace_probe_log_err(len, BAD_ADDR_SUFFIX);
-			return -EINVAL;
-		}
-		*symbol = kmemdup_nul(argv[1], len, GFP_KERNEL);
-	} else
-		*symbol = kstrdup(argv[1], GFP_KERNEL);
-	if (!*symbol)
-		return -ENOMEM;
+	if (!in || !base || !is_return || !list_mode || !filter || !nofilter)
+		return -EINVAL;
 
-	if (*is_return)
-		return 0;
+	*base = NULL; *filter = NULL; *nofilter = NULL;
+	*is_return = false; *list_mode = false;
 
 	if (is_tracepoint) {
-		tmp = *symbol;
-		while (*tmp && (isalnum(*tmp) || *tmp == '_'))
-			tmp++;
-		if (*tmp) {
-			/* find a wrong character. */
-			trace_probe_log_err(tmp - *symbol, BAD_TP_NAME);
-			kfree(*symbol);
-			*symbol = NULL;
+		if (strchr(in, ',') || strchr(in, ':'))
 			return -EINVAL;
-		}
+		if (strstr(in, "%return"))
+			return -EINVAL;
+		for (p = in; *p; p++)
+			if (!isalnum(*p) && *p != '_')
+				return -EINVAL;
+		b = kstrdup(in, GFP_KERNEL);
+		if (!b)
+			return -ENOMEM;
+		*base = no_free_ptr(b);
+		return 0;
 	}
 
-	/* If there is $retval, this should be a return fprobe. */
-	for (i = 2; i < argc; i++) {
-		tmp = strstr(argv[i], "$retval");
-		if (tmp && !isalnum(tmp[7]) && tmp[7] != '_') {
-			if (is_tracepoint) {
-				trace_probe_log_set_index(i);
-				trace_probe_log_err(tmp - argv[i], RETVAL_ON_PROBE);
-				kfree(*symbol);
-				*symbol = NULL;
+	work = kstrdup(in, GFP_KERNEL);
+	if (!work)
+		return -ENOMEM;
+
+	p = strstr(work, "%return");
+	if (p && p[7] == '\0') {
+		*is_return = true;
+		legacy_ret = true;
+		*(char *)p = '\0';
+	} else {
+		/*
+		 * If "symbol:entry" or "symbol:exit" is given, it is new
+		 * style probe.
+		 */
+		p = strrchr(work, ':');
+		if (p) {
+			if (!strcmp(p, ":exit")) {
+				*is_return = true;
+				*(char *)p = '\0';
+			} else if (!strcmp(p, ":entry")) {
+				*(char *)p = '\0';
+			} else {
 				return -EINVAL;
 			}
-			*is_return = true;
-			break;
 		}
 	}
-	return 0;
+
+	list = !!strchr(work, ',');
+	
+	if (list && legacy_ret) {
+		return -EINVAL;
+	}
+
+	if (legacy_ret)
+		*is_return = true;
+
+	b = kstrdup(work, GFP_KERNEL);
+	if (!b)
+		return -ENOMEM;
+
+	if (list) {
+		char *tmp = b, *tok;
+		size_t fsz, nfsz;
+
+		fsz = nfsz = strlen(b) + 1;
+
+		f = kzalloc(fsz, GFP_KERNEL);
+		nf = kzalloc(nfsz, GFP_KERNEL);
+		if (!f || !nf)
+			return -ENOMEM;
+
+		while ((tok = strsep(&tmp, ",")) != NULL) {
+			char *dst;
+			bool neg = (*tok == '!');
+
+			if (*tok == '\0') {
+				trace_probe_log_err(tmp - b - 1, BAD_TP_NAME);
+				return -EINVAL;
+
+			if (neg)
+				tok++;
+			dst = neg ? nf : f;
+			if (dst[0] != '\0')
+				strcat(dst, ",");
+			strcat(dst, tok);
+		}
+		*list_mode = true;
+	}
+
+	*base = no_free_ptr(b);
+	*filter = no_free_ptr(f);
+	*nofilter = no_free_ptr(nf);
+
+	return ret;
 }
 
 static int trace_fprobe_create_internal(int argc, const char *argv[],
@@ -1241,6 +1310,8 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
 	const char *event = NULL, *group = FPROBE_EVENT_SYSTEM;
 	struct module *mod __free(module_put) = NULL;
 	const char **new_argv __free(kfree) = NULL;
+	char *parsed_nofilter __free(kfree) = NULL;
+	char *parsed_filter __free(kfree) = NULL;
 	char *symbol __free(kfree) = NULL;
 	char *ebuf __free(kfree) = NULL;
 	char *gbuf __free(kfree) = NULL;
@@ -1249,6 +1320,7 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
 	char *dbuf __free(kfree) = NULL;
 	int i, new_argc = 0, ret = 0;
 	bool is_tracepoint = false;
+	bool list_mode = false;
 	bool is_return = false;
 
 	if ((argv[0][0] != 'f' && argv[0][0] != 't') || argc < 2)
@@ -1270,11 +1342,26 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
 
 	trace_probe_log_set_index(1);
 
-	/* a symbol(or tracepoint) must be specified */
-	ret = parse_symbol_and_return(argc, argv, &symbol, &is_return, is_tracepoint);
+	/* Parse spec early (single vs list, suffix, base symbol) */
+	ret = parse_fprobe_spec(argv[1], is_tracepoint, &symbol, &is_return,
+			&list_mode, &parsed_filter, &parsed_nofilter);
 	if (ret < 0)
 		return -EINVAL;
 
+	for (i = 2; i < argc; i++) {
+		char *tmp = strstr(argv[i], "$retval");
+
+		if (tmp && !isalnum(tmp[7]) && tmp[7] != '_') {
+			if (is_tracepoint) {
+				trace_probe_log_set_index(i);
+				trace_probe_log_err(tmp - argv[i], RETVAL_ON_PROBE);
+				return -EINVAL;
+			}
+			is_return = true;
+			break;
+		}
+	}
+
 	trace_probe_log_set_index(0);
 	if (event) {
 		gbuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL);
@@ -1287,6 +1374,15 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
 	}
 
 	if (!event) {
+		/*
+		 * Event name rules:
+		 * - For list/wildcard: require explicit [GROUP/]EVENT
+		 * - For single literal: autogenerate symbol__entry/symbol__exit
+		 */
+		if (list_mode || has_wildcard(symbol)) {
+			trace_probe_log_err(0, NO_GROUP_NAME);
+			return -EINVAL;
+		}
 		ebuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL);
 		if (!ebuf)
 			return -ENOMEM;
@@ -1322,7 +1418,8 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
 							NULL, NULL, NULL, sbuf);
 		}
 	}
-	if (!ctx->funcname)
+
+	if (!list_mode && !has_wildcard(symbol) && !is_tracepoint)
 		ctx->funcname = symbol;
 
 	abuf = kmalloc(MAX_BTF_ARGS_LEN, GFP_KERNEL);
@@ -1356,6 +1453,21 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
 		return ret;
 	}
 
+	/* carry list parsing result into tf */
+	if (!is_tracepoint) {
+		tf->list_mode = list_mode;
+		if (parsed_filter) {
+			tf->filter = kstrdup(parsed_filter, GFP_KERNEL);
+			if (!tf->filter)
+				return -ENOMEM;
+		}
+		if (parsed_nofilter) {
+			tf->nofilter = kstrdup(parsed_nofilter, GFP_KERNEL);
+			if (!tf->nofilter)
+				return -ENOMEM;
+		}
+	}
+
 	/* parse arguments */
 	for (i = 0; i < argc; i++) {
 		trace_probe_log_set_index(i + 2);
@@ -1442,8 +1554,9 @@ static int trace_fprobe_show(struct seq_file *m, struct dyn_event *ev)
 	seq_printf(m, ":%s/%s", trace_probe_group_name(&tf->tp),
 				trace_probe_name(&tf->tp));
 
-	seq_printf(m, " %s%s", trace_fprobe_symbol(tf),
-			       trace_fprobe_is_return(tf) ? "%return" : "");
+	seq_printf(m, " %s", trace_fprobe_symbol(tf));
+	if (!trace_fprobe_is_tracepoint(tf) && trace_fprobe_is_return(tf))
+		seq_puts(m, ":exit");
 
 	for (i = 0; i < tf->tp.nr_args; i++)
 		seq_printf(m, " %s=%s", tf->tp.args[i].name, tf->tp.args[i].comm);
-- 
2.43.0

Re: [PATCH v5 v5 2/3] tracing/fprobe: Support comma-separated symbols and :entry/:exit

[kernel test robot]

Hi Seokwoo,

kernel test robot noticed the following build errors:

[auto build test ERROR on trace/for-next]
[also build test ERROR on linus/master v6.19-rc5 next-20260116]
[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/Seokwoo-Chung-Ryan/docs-tracing-fprobe-Document-list-filters-and-entry-exit/20260118-092055
base:   https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace for-next
patch link:    https://lore.kernel.org/r/20260118011815.56516-3-seokwoo.chung130%40gmail.com
patch subject: [PATCH v5 v5 2/3] tracing/fprobe: Support comma-separated symbols and :entry/:exit
config: x86_64-randconfig-012-20260118 (https://download.01.org/0day-ci/archive/20260118/202601181443.vv7qeHyx-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260118/202601181443.vv7qeHyx-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/202601181443.vv7qeHyx-lkp@intel.com/

All errors (new ones prefixed by >>):

   kernel/trace/trace_fprobe.c: In function 'parse_fprobe_spec':
   kernel/trace/trace_fprobe.c:1282:12: error: invalid storage class for function 'trace_fprobe_create_internal'
    1282 | static int trace_fprobe_create_internal(int argc, const char *argv[],
         |            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/trace/trace_fprobe.c:1513:12: error: invalid storage class for function 'trace_fprobe_create_cb'
    1513 | static int trace_fprobe_create_cb(int argc, const char *argv[])
         |            ^~~~~~~~~~~~~~~~~~~~~~
   kernel/trace/trace_fprobe.c:1530:12: error: invalid storage class for function 'trace_fprobe_create'
    1530 | static int trace_fprobe_create(const char *raw_command)
         |            ^~~~~~~~~~~~~~~~~~~
   kernel/trace/trace_fprobe.c:1535:12: error: invalid storage class for function 'trace_fprobe_release'
    1535 | static int trace_fprobe_release(struct dyn_event *ev)
         |            ^~~~~~~~~~~~~~~~~~~~
   kernel/trace/trace_fprobe.c:1545:12: error: invalid storage class for function 'trace_fprobe_show'
    1545 | static int trace_fprobe_show(struct seq_file *m, struct dyn_event *ev)
         |            ^~~~~~~~~~~~~~~~~
   kernel/trace/trace_fprobe.c:1572:12: error: invalid storage class for function 'enable_trace_fprobe'
    1572 | static int enable_trace_fprobe(struct trace_event_call *call,
         |            ^~~~~~~~~~~~~~~~~~~
   kernel/trace/trace_fprobe.c:1608:12: error: invalid storage class for function 'disable_trace_fprobe'
    1608 | static int disable_trace_fprobe(struct trace_event_call *call,
         |            ^~~~~~~~~~~~~~~~~~~~
   kernel/trace/trace_fprobe.c:1653:12: error: invalid storage class for function 'fprobe_register'
    1653 | static int fprobe_register(struct trace_event_call *event,
         |            ^~~~~~~~~~~~~~~
   kernel/trace/trace_fprobe.c:1683:19: error: invalid storage class for function 'init_fprobe_trace_early'
    1683 | static __init int init_fprobe_trace_early(void)
         |                   ^~~~~~~~~~~~~~~~~~~~~~~
   In file included from include/linux/fprobe.h:6,
                    from kernel/trace/trace_fprobe.c:8:
>> include/linux/compiler.h:284:51: error: initializer element is not constant
     284 |         __UNIQUE_ID(__PASTE(addressable_, sym)) = (void *)(uintptr_t)&sym;
         |                                                   ^
   include/linux/compiler.h:287:9: note: in expansion of macro '___ADDRESSABLE'
     287 |         ___ADDRESSABLE(sym, __section(".discard.addressable"))
         |         ^~~~~~~~~~~~~~
   include/linux/init.h:251:9: note: in expansion of macro '__ADDRESSABLE'
     251 |         __ADDRESSABLE(fn)
         |         ^~~~~~~~~~~~~
   include/linux/init.h:256:9: note: in expansion of macro '__define_initcall_stub'
     256 |         __define_initcall_stub(__stub, fn)                      \
         |         ^~~~~~~~~~~~~~~~~~~~~~
   include/linux/init.h:269:9: note: in expansion of macro '____define_initcall'
     269 |         ____define_initcall(fn,                                 \
         |         ^~~~~~~~~~~~~~~~~~~
   include/linux/init.h:275:9: note: in expansion of macro '__unique_initcall'
     275 |         __unique_initcall(fn, id, __sec, __initcall_id(fn))
         |         ^~~~~~~~~~~~~~~~~
   include/linux/init.h:277:35: note: in expansion of macro '___define_initcall'
     277 | #define __define_initcall(fn, id) ___define_initcall(fn, id, .initcall##id)
         |                                   ^~~~~~~~~~~~~~~~~~
   include/linux/init.h:295:41: note: in expansion of macro '__define_initcall'
     295 | #define core_initcall(fn)               __define_initcall(fn, 1)
         |                                         ^~~~~~~~~~~~~~~~~
   kernel/trace/trace_fprobe.c:1702:1: note: in expansion of macro 'core_initcall'
    1702 | core_initcall(init_fprobe_trace_early);
         | ^~~~~~~~~~~~~
   kernel/trace/trace_fprobe.c:1702:1: error: expected declaration or statement at end of input
   kernel/trace/trace_fprobe.c: At top level:
   kernel/trace/trace_fprobe.c:28:12: warning: 'trace_fprobe_create' used but never defined
      28 | static int trace_fprobe_create(const char *raw_command);
         |            ^~~~~~~~~~~~~~~~~~~
   kernel/trace/trace_fprobe.c:29:12: warning: 'trace_fprobe_show' used but never defined
      29 | static int trace_fprobe_show(struct seq_file *m, struct dyn_event *ev);
         |            ^~~~~~~~~~~~~~~~~
   kernel/trace/trace_fprobe.c:30:12: warning: 'trace_fprobe_release' used but never defined
      30 | static int trace_fprobe_release(struct dyn_event *ev);
         |            ^~~~~~~~~~~~~~~~~~~~
   kernel/trace/trace_fprobe.c:741:12: warning: 'fprobe_register' used but never defined
     741 | static int fprobe_register(struct trace_event_call *event,
         |            ^~~~~~~~~~~~~~~
   kernel/trace/trace_fprobe.c:1653:12: warning: 'fprobe_register' defined but not used [-Wunused-function]
    1653 | static int fprobe_register(struct trace_event_call *event,
         |            ^~~~~~~~~~~~~~~
   kernel/trace/trace_fprobe.c:1545:12: warning: 'trace_fprobe_show' defined but not used [-Wunused-function]
    1545 | static int trace_fprobe_show(struct seq_file *m, struct dyn_event *ev)
         |            ^~~~~~~~~~~~~~~~~
   kernel/trace/trace_fprobe.c:1535:12: warning: 'trace_fprobe_release' defined but not used [-Wunused-function]
    1535 | static int trace_fprobe_release(struct dyn_event *ev)
         |            ^~~~~~~~~~~~~~~~~~~~
   kernel/trace/trace_fprobe.c:1530:12: warning: 'trace_fprobe_create' defined but not used [-Wunused-function]
    1530 | static int trace_fprobe_create(const char *raw_command)
         |            ^~~~~~~~~~~~~~~~~~~


vim +284 include/linux/compiler.h

0ef8047b737d74 Juergen Gross  2024-11-29  275  
7290d58095712a Ard Biesheuvel 2018-08-21  276  /*
7290d58095712a Ard Biesheuvel 2018-08-21  277   * Force the compiler to emit 'sym' as a symbol, so that we can reference
7290d58095712a Ard Biesheuvel 2018-08-21  278   * it from inline assembler. Necessary in case 'sym' could be inlined
7290d58095712a Ard Biesheuvel 2018-08-21  279   * otherwise, or eliminated entirely due to lack of references that are
7290d58095712a Ard Biesheuvel 2018-08-21  280   * visible to the compiler.
7290d58095712a Ard Biesheuvel 2018-08-21  281   */
92efda8eb15295 Sami Tolvanen  2022-09-08  282  #define ___ADDRESSABLE(sym, __attrs)						\
92efda8eb15295 Sami Tolvanen  2022-09-08  283  	static void * __used __attrs						\
9f14f1f91883aa Josh Poimboeuf 2025-09-17 @284  	__UNIQUE_ID(__PASTE(addressable_, sym)) = (void *)(uintptr_t)&sym;
0ef8047b737d74 Juergen Gross  2024-11-29  285  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v5 v5 2/3] tracing/fprobe: Support comma-separated symbols and :entry/:exit

[Masami Hiramatsu]

On Sat, 17 Jan 2026 20:18:14 -0500
"Seokwoo Chung (Ryan)" <seokwoo.chung130@gmail.com> wrote:

> - Update DEFINE_FREE to use standard __free()
> - Extend fprobe to support multiple symbols per event. Add parsing logic for
>   lists, ! exclusions, and explicit suffixes. Update tracefs/README to reflect
>   the new syntax
> 
> Signed-off-by: Seokwoo Chung (Ryan) <seokwoo.chung130@gmail.com>
> ---
>  kernel/trace/trace.c        |   3 +-
>  kernel/trace/trace_fprobe.c | 209 +++++++++++++++++++++++++++---------
>  2 files changed, 163 insertions(+), 49 deletions(-)
> 
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index baec63134ab6..10cdcc7b194e 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -5578,7 +5578,8 @@ static const char readme_msg[] =
>  	"\t           r[maxactive][:[<group>/][<event>]] <place> [<args>]\n"
>  #endif
>  #ifdef CONFIG_FPROBE_EVENTS
> -	"\t           f[:[<group>/][<event>]] <func-name>[%return] [<args>]\n"
> +	"\t           f[:[<group>/][<event>]] <func-name>[:entry|:exit] [<args>]\n"
> +	"\t		(single symbols still accept %return)\n"
>  	"\t           t[:[<group>/][<event>]] <tracepoint> [<args>]\n"
>  #endif
>  #ifdef CONFIG_HIST_TRIGGERS
> diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
> index 262c0556e4af..5a2a41eea603 100644
> --- a/kernel/trace/trace_fprobe.c
> +++ b/kernel/trace/trace_fprobe.c
> @@ -187,11 +187,14 @@ DEFINE_FREE(tuser_put, struct tracepoint_user *,
>   */
>  struct trace_fprobe {
>  	struct dyn_event	devent;
> +	char			*filter;
>  	struct fprobe		fp;
> +	bool			list_mode;
> +	char			*nofilter;
>  	const char		*symbol;
> +	struct trace_probe	tp;
>  	bool			tprobe;
>  	struct tracepoint_user	*tuser;
> -	struct trace_probe	tp;
>  };
>  
>  static bool is_trace_fprobe(struct dyn_event *ev)
> @@ -559,6 +562,8 @@ static void free_trace_fprobe(struct trace_fprobe *tf)
>  		trace_probe_cleanup(&tf->tp);
>  		if (tf->tuser)
>  			tracepoint_user_put(tf->tuser);
> +		kfree(tf->filter);
> +		kfree(tf->nofilter);
>  		kfree(tf->symbol);
>  		kfree(tf);
>  	}
> @@ -838,7 +843,12 @@ static int __register_trace_fprobe(struct trace_fprobe *tf)
>  	if (trace_fprobe_is_tracepoint(tf))
>  		return __regsiter_tracepoint_fprobe(tf);
>  
> -	/* TODO: handle filter, nofilter or symbol list */
> +	/* Registration path:
> +	 * - list_mode: pass filter/nofilter
> +	 * - single: pass symbol only (legacy)
> +	 */
> +	if (tf->list_mode)
> +		return register_fprobe(&tf->fp, tf->filter, tf->nofilter);
>  	return register_fprobe(&tf->fp, tf->symbol, NULL);
>  }
>  
> @@ -1154,60 +1164,119 @@ static struct notifier_block tprobe_event_module_nb = {
>  };
>  #endif /* CONFIG_MODULES */
>  
> -static int parse_symbol_and_return(int argc, const char *argv[],
> -				   char **symbol, bool *is_return,
> -				   bool is_tracepoint)
> +static bool has_wildcard(const char *s)
>  {
> -	char *tmp = strchr(argv[1], '%');
> -	int i;
> +	return s && (strchr(s, '*') || strchr(s, '?'));
> +}
>  
> -	if (tmp) {
> -		int len = tmp - argv[1];
> +static int parse_fprobe_spec(const char *in, bool is_tracepoint,
> +		char **base, bool *is_return, bool *list_mode,
> +		char **filter, char **nofilter)
> +{
> +	char *work __free(kfree) = NULL;
> +	char *b __free(kfree) = NULL;
> +	char *f __free(kfree) = NULL;
> +	char *nf __free(kfree) = NULL;
> +	bool legacy_ret = false;
> +	bool list = false;
> +	const char *p;
> +	int ret = 0;
>  
> -		if (!is_tracepoint && !strcmp(tmp, "%return")) {
> -			*is_return = true;
> -		} else {
> -			trace_probe_log_err(len, BAD_ADDR_SUFFIX);
> -			return -EINVAL;
> -		}
> -		*symbol = kmemdup_nul(argv[1], len, GFP_KERNEL);
> -	} else
> -		*symbol = kstrdup(argv[1], GFP_KERNEL);
> -	if (!*symbol)
> -		return -ENOMEM;
> +	if (!in || !base || !is_return || !list_mode || !filter || !nofilter)
> +		return -EINVAL;
>  
> -	if (*is_return)
> -		return 0;
> +	*base = NULL; *filter = NULL; *nofilter = NULL;
> +	*is_return = false; *list_mode = false;
>  
>  	if (is_tracepoint) {
> -		tmp = *symbol;
> -		while (*tmp && (isalnum(*tmp) || *tmp == '_'))
> -			tmp++;
> -		if (*tmp) {
> -			/* find a wrong character. */
> -			trace_probe_log_err(tmp - *symbol, BAD_TP_NAME);
> -			kfree(*symbol);
> -			*symbol = NULL;
> +		if (strchr(in, ',') || strchr(in, ':'))
>  			return -EINVAL;
> -		}
> +		if (strstr(in, "%return"))
> +			return -EINVAL;

These checks look redundant. because below ensures there is no
',', '/' and '%'.

> +		for (p = in; *p; p++)
> +			if (!isalnum(*p) && *p != '_')
> +				return -EINVAL;

Please report parse error via trace_probe_log_err() function so that
user can check what was wrong via tracefs/error_log file. E.g.

	trace_probe_log_err(p - in, BAD_TP_NAME);


> +		b = kstrdup(in, GFP_KERNEL);
> +		if (!b)
> +			return -ENOMEM;

Note: ENOMEM does not need to report via error_log.

> +		*base = no_free_ptr(b);
> +		return 0;
>  	}
>  
> -	/* If there is $retval, this should be a return fprobe. */
> -	for (i = 2; i < argc; i++) {
> -		tmp = strstr(argv[i], "$retval");
> -		if (tmp && !isalnum(tmp[7]) && tmp[7] != '_') {
> -			if (is_tracepoint) {
> -				trace_probe_log_set_index(i);
> -				trace_probe_log_err(tmp - argv[i], RETVAL_ON_PROBE);
> -				kfree(*symbol);
> -				*symbol = NULL;
> +	work = kstrdup(in, GFP_KERNEL);
> +	if (!work)
> +		return -ENOMEM;
> +
> +	p = strstr(work, "%return");
> +	if (p && p[7] == '\0') {
> +		*is_return = true;
> +		legacy_ret = true;
> +		*(char *)p = '\0';
> +	} else {
> +		/*
> +		 * If "symbol:entry" or "symbol:exit" is given, it is new
> +		 * style probe.
> +		 */
> +		p = strrchr(work, ':');
> +		if (p) {
> +			if (!strcmp(p, ":exit")) {
> +				*is_return = true;
> +				*(char *)p = '\0';
> +			} else if (!strcmp(p, ":entry")) {
> +				*(char *)p = '\0';
> +			} else {
>  				return -EINVAL;
>  			}
> -			*is_return = true;
> -			break;
>  		}
>  	}
> -	return 0;
> +
> +	list = !!strchr(work, ',');
> +	
> +	if (list && legacy_ret) {
> +		return -EINVAL;
> +	}

You don't need braces for the above block.

> +
> +	if (legacy_ret)
> +		*is_return = true;
> +
> +	b = kstrdup(work, GFP_KERNEL);
> +	if (!b)
> +		return -ENOMEM;
> +
> +	if (list) {

Could you make this block as an independent function?

> +		char *tmp = b, *tok;
> +		size_t fsz, nfsz;
> +
> +		fsz = nfsz = strlen(b) + 1;
> +
> +		f = kzalloc(fsz, GFP_KERNEL);
> +		nf = kzalloc(nfsz, GFP_KERNEL);
> +		if (!f || !nf)
> +			return -ENOMEM;
> +
> +		while ((tok = strsep(&tmp, ",")) != NULL) {
> +			char *dst;
> +			bool neg = (*tok == '!');
> +
> +			if (*tok == '\0') {
> +				trace_probe_log_err(tmp - b - 1, BAD_TP_NAME);
> +				return -EINVAL;

You missed close brace '}' here. And that makes the build failure.
Can you fix it and run all tests under tools/testing/selftests/ftrace/
with your change?

Thank you,


> +
> +			if (neg)
> +				tok++;
> +			dst = neg ? nf : f;
> +			if (dst[0] != '\0')
> +				strcat(dst, ",");
> +			strcat(dst, tok);
> +		}
> +		*list_mode = true;
> +	}
> +
> +	*base = no_free_ptr(b);
> +	*filter = no_free_ptr(f);
> +	*nofilter = no_free_ptr(nf);
> +
> +	return ret;
>  }
>  
>  static int trace_fprobe_create_internal(int argc, const char *argv[],
> @@ -1241,6 +1310,8 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
>  	const char *event = NULL, *group = FPROBE_EVENT_SYSTEM;
>  	struct module *mod __free(module_put) = NULL;
>  	const char **new_argv __free(kfree) = NULL;
> +	char *parsed_nofilter __free(kfree) = NULL;
> +	char *parsed_filter __free(kfree) = NULL;
>  	char *symbol __free(kfree) = NULL;
>  	char *ebuf __free(kfree) = NULL;
>  	char *gbuf __free(kfree) = NULL;
> @@ -1249,6 +1320,7 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
>  	char *dbuf __free(kfree) = NULL;
>  	int i, new_argc = 0, ret = 0;
>  	bool is_tracepoint = false;
> +	bool list_mode = false;
>  	bool is_return = false;
>  
>  	if ((argv[0][0] != 'f' && argv[0][0] != 't') || argc < 2)
> @@ -1270,11 +1342,26 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
>  
>  	trace_probe_log_set_index(1);
>  
> -	/* a symbol(or tracepoint) must be specified */
> -	ret = parse_symbol_and_return(argc, argv, &symbol, &is_return, is_tracepoint);
> +	/* Parse spec early (single vs list, suffix, base symbol) */
> +	ret = parse_fprobe_spec(argv[1], is_tracepoint, &symbol, &is_return,
> +			&list_mode, &parsed_filter, &parsed_nofilter);
>  	if (ret < 0)
>  		return -EINVAL;
>  
> +	for (i = 2; i < argc; i++) {
> +		char *tmp = strstr(argv[i], "$retval");
> +
> +		if (tmp && !isalnum(tmp[7]) && tmp[7] != '_') {
> +			if (is_tracepoint) {
> +				trace_probe_log_set_index(i);
> +				trace_probe_log_err(tmp - argv[i], RETVAL_ON_PROBE);
> +				return -EINVAL;
> +			}
> +			is_return = true;
> +			break;
> +		}
> +	}
> +
>  	trace_probe_log_set_index(0);
>  	if (event) {
>  		gbuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL);
> @@ -1287,6 +1374,15 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
>  	}
>  
>  	if (!event) {
> +		/*
> +		 * Event name rules:
> +		 * - For list/wildcard: require explicit [GROUP/]EVENT
> +		 * - For single literal: autogenerate symbol__entry/symbol__exit
> +		 */
> +		if (list_mode || has_wildcard(symbol)) {
> +			trace_probe_log_err(0, NO_GROUP_NAME);
> +			return -EINVAL;
> +		}
>  		ebuf = kmalloc(MAX_EVENT_NAME_LEN, GFP_KERNEL);
>  		if (!ebuf)
>  			return -ENOMEM;
> @@ -1322,7 +1418,8 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
>  							NULL, NULL, NULL, sbuf);
>  		}
>  	}
> -	if (!ctx->funcname)
> +
> +	if (!list_mode && !has_wildcard(symbol) && !is_tracepoint)
>  		ctx->funcname = symbol;
>  
>  	abuf = kmalloc(MAX_BTF_ARGS_LEN, GFP_KERNEL);
> @@ -1356,6 +1453,21 @@ static int trace_fprobe_create_internal(int argc, const char *argv[],
>  		return ret;
>  	}
>  
> +	/* carry list parsing result into tf */
> +	if (!is_tracepoint) {
> +		tf->list_mode = list_mode;
> +		if (parsed_filter) {
> +			tf->filter = kstrdup(parsed_filter, GFP_KERNEL);
> +			if (!tf->filter)
> +				return -ENOMEM;
> +		}
> +		if (parsed_nofilter) {
> +			tf->nofilter = kstrdup(parsed_nofilter, GFP_KERNEL);
> +			if (!tf->nofilter)
> +				return -ENOMEM;
> +		}
> +	}
> +
>  	/* parse arguments */
>  	for (i = 0; i < argc; i++) {
>  		trace_probe_log_set_index(i + 2);
> @@ -1442,8 +1554,9 @@ static int trace_fprobe_show(struct seq_file *m, struct dyn_event *ev)
>  	seq_printf(m, ":%s/%s", trace_probe_group_name(&tf->tp),
>  				trace_probe_name(&tf->tp));
>  
> -	seq_printf(m, " %s%s", trace_fprobe_symbol(tf),
> -			       trace_fprobe_is_return(tf) ? "%return" : "");
> +	seq_printf(m, " %s", trace_fprobe_symbol(tf));
> +	if (!trace_fprobe_is_tracepoint(tf) && trace_fprobe_is_return(tf))
> +		seq_puts(m, ":exit");
>  
>  	for (i = 0; i < tf->tp.nr_args; i++)
>  		seq_printf(m, " %s=%s", tf->tp.args[i].name, tf->tp.args[i].comm);
> -- 
> 2.43.0
> 


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>

[PATCH v5 v5 3/3] selftests/ftrace: Add accept cases for fprobe list syntax

[Seokwoo Chung (Ryan)]

Add selftest for comma-separated symbol lists, exclusion (!), and explicit
:entry/:exit suffixes. Verify that excluded symbols are not attached and
that enabled_functions shows the correct probes.

Signed-off-by: Seokwoo Chung (Ryan) <seokwoo.chung130@gmail.com>
---
 .../ftrace/test.d/dynevent/fprobe_list.tc     | 92 +++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/dynevent/fprobe_list.tc

diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_list.tc b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_list.tc
new file mode 100644
index 000000000000..45e57c6f487d
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_list.tc
@@ -0,0 +1,92 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# description: Fprobe event list syntax and :entry/:exit suffixes
+# requires: dynamic_events "f[:[<group>/][<event>]] <func-name>[:entry|:exit] [<args>]":README
+
+# Setup symbols to test. These are common kernel functions.
+PLACE=vfs_read
+PLACE2=vfs_write
+PLACE3=vfs_open
+
+echo 0 > events/enable
+echo > dynamic_events
+
+# Get baseline count of enabled functions (should be 0 if clean, but be safe)
+if [ -f enabled_functions ]; then
+	ocnt=`cat enabled_functions | wc -l`
+else
+	ocnt=0
+fi
+
+# Test 1: List default (entry) with exclusion
+# Target: Trace vfs_read and vfs_open, but EXCLUDE vfs_write
+echo "f:test/list_entry $PLACE,!$PLACE2,$PLACE3" >> dynamic_events
+grep -q "test/list_entry" dynamic_events
+test -d events/test/list_entry
+
+echo 1 > events/test/list_entry/enable
+
+grep -q "$PLACE" enabled_functions
+grep -q "$PLACE3" enabled_functions
+! grep -q "$PLACE2" enabled_functions
+
+# Check count (Baseline + 2 new functions)
+cnt=`cat enabled_functions | wc -l`
+if [ $cnt -ne $((ocnt + 2)) ]; then
+	exit_fail
+fi
+
+# Cleanup Test 1
+echo 0 > events/test/list_entry/enable
+echo "-:test/list_entry" >> dynamic_events
+! grep -q "test/list_entry" dynamic_events
+
+# Count should return to baseline
+cnt=`cat enabled_functions | wc -l`
+if [ $cnt -ne $ocnt ]; then
+	exit_fail
+fi
+
+# Test 2: List with explicit :entry suffix
+# (Should behave exactly like Test 1)
+echo "f:test/list_entry_exp $PLACE,!$PLACE2,$PLACE3:entry" >> dynamic_events
+grep -q "test/list_entry_exp" dynamic_events
+test -d events/test/list_entry_exp
+
+echo 1 > events/test/list_entry_exp/enable
+
+grep -q "$PLACE" enabled_functions
+grep -q "$PLACE3" enabled_functions
+! grep -q "$PLACE2" enabled_functions
+
+cnt=`cat enabled_functions | wc -l`
+if [ $cnt -ne $((ocnt + 2)) ]; then
+	exit_fail
+fi
+
+# Cleanup Test 2
+echo 0 > events/test/list_entry_exp/enable
+echo "-:test/list_entry_exp" >> dynamic_events
+
+# Test 3: List with :exit suffix
+echo "f:test/list_exit $PLACE,!$PLACE2,$PLACE3:exit" >> dynamic_events
+grep -q "test/list_exit" dynamic_events
+test -d events/test/list_exit
+
+echo 1 > events/test/list_exit/enable
+
+# Even for return probes, enabled_functions lists the attached symbols
+grep -q "$PLACE" enabled_functions
+grep -q "$PLACE3" enabled_functions
+! grep -q "$PLACE2" enabled_functions
+
+cnt=`cat enabled_functions | wc -l`
+if [ $cnt -ne $((ocnt + 2)) ]; then
+	exit_fail
+fi
+
+# Cleanup Test 3
+echo 0 > events/test/list_exit/enable
+echo "-:test/list_exit" >> dynamic_events
+
+clear_trace
-- 
2.43.0