[PATCH] ftrace: Support full glob matching

[PATCH] ftrace: Support full glob matching

[Masami Hiramatsu]

Use glob_match() to support flexible glob wildcards (*,?)
and character classes ([) for ftrace.
Since the full glob matching is slower than the current
partial matching routines(*pat, pat*, *pat*), this leaves
those routines and just add MATCH_GLOB for complex glob
expression.

e.g.
----
[root@localhost tracing]# echo 'sched*group' > set_ftrace_filter
[root@localhost tracing]# cat set_ftrace_filter
sched_free_group
sched_change_group
sched_create_group
sched_online_group
sched_destroy_group
sched_offline_group
[root@localhost tracing]# echo '[Ss]y[Ss]_*' > set_ftrace_filter
[root@localhost tracing]# head set_ftrace_filter
sys_arch_prctl
sys_rt_sigreturn
sys_ioperm
SyS_iopl
sys_modify_ldt
SyS_mmap
SyS_set_thread_area
SyS_get_thread_area
SyS_set_tid_address
sys_fork
----

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 Documentation/trace/events.txt     |    9 +++------
 Documentation/trace/ftrace.txt     |    9 +++------
 kernel/trace/Kconfig               |    2 ++
 kernel/trace/ftrace.c              |    4 ++++
 kernel/trace/trace.c               |    2 +-
 kernel/trace/trace.h               |    2 ++
 kernel/trace/trace_events_filter.c |   17 ++++++++++++++++-
 7 files changed, 31 insertions(+), 14 deletions(-)

diff --git a/Documentation/trace/events.txt b/Documentation/trace/events.txt
index 08d74d7..2cc08d4 100644
--- a/Documentation/trace/events.txt
+++ b/Documentation/trace/events.txt
@@ -189,16 +189,13 @@ And for string fields they are:
 
 ==, !=, ~
 
-The glob (~) only accepts a wild card character (*) at the start and or
-end of the string. For example:
+The glob (~) accepts a wild card character (*,?) and character classes
+([). For example:
 
   prev_comm ~ "*sh"
   prev_comm ~ "sh*"
   prev_comm ~ "*sh*"
-
-But does not allow for it to be within the string:
-
-  prev_comm ~ "ba*sh"   <-- is invalid
+  prev_comm ~ "ba*sh"
 
 5.2 Setting filters
 -------------------
diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
index a6b3705..b26abc7 100644
--- a/Documentation/trace/ftrace.txt
+++ b/Documentation/trace/ftrace.txt
@@ -2218,16 +2218,13 @@ hrtimer_interrupt
 sys_nanosleep
 
 
-Perhaps this is not enough. The filters also allow simple wild
-cards. Only the following are currently available
+Perhaps this is not enough. The filters also allow glob(7) matching.
 
   <match>*  - will match functions that begin with <match>
   *<match>  - will match functions that end with <match>
   *<match>* - will match functions that have <match> in it
-
-These are the only wild cards which are supported.
-
-  <match>*<match> will not work.
+  <match1>*<match2> - will match functions that begin with
+                      <match1> and end with <match2>
 
 Note: It is better to use quotes to enclose the wild cards,
       otherwise the shell may expand the parameters into names
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index ba33267..aa6eb15 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -70,6 +70,7 @@ config FTRACE_NMI_ENTER
 
 config EVENT_TRACING
 	select CONTEXT_SWITCH_TRACER
+        select GLOB
 	bool
 
 config CONTEXT_SWITCH_TRACER
@@ -133,6 +134,7 @@ config FUNCTION_TRACER
 	select KALLSYMS
 	select GENERIC_TRACER
 	select CONTEXT_SWITCH_TRACER
+        select GLOB
 	help
 	  Enable the kernel to trace every kernel function. This is done
 	  by using a compiler feature to insert a small, 5-byte No-Operation
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 84752c8..5741184 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3493,6 +3493,10 @@ static int ftrace_match(char *str, struct ftrace_glob *g)
 		    memcmp(str + slen - g->len, g->search, g->len) == 0)
 			matched = 1;
 		break;
+	case MATCH_GLOB:
+		if (glob_match(g->search, str))
+			matched = 1;
+		break;
 	}
 
 	return matched;
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 37824d9..ae343e7 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4065,7 +4065,7 @@ static const char readme_msg[] =
 	"\n  available_filter_functions - list of functions that can be filtered on\n"
 	"  set_ftrace_filter\t- echo function name in here to only trace these\n"
 	"\t\t\t  functions\n"
-	"\t     accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
+	"\t     accepts: func_full_name or glob-matching-pattern\n"
 	"\t     modules: Can select a group via module\n"
 	"\t      Format: :mod:<module-name>\n"
 	"\t     example: echo :mod:ext3 > set_ftrace_filter\n"
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index f783df4..eac2eda 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -15,6 +15,7 @@
 #include <linux/trace_events.h>
 #include <linux/compiler.h>
 #include <linux/trace_seq.h>
+#include <linux/glob.h>
 
 #ifdef CONFIG_FTRACE_SYSCALLS
 #include <asm/unistd.h>		/* For NR_SYSCALLS	     */
@@ -1252,6 +1253,7 @@ enum regex_type {
 	MATCH_FRONT_ONLY,
 	MATCH_MIDDLE_ONLY,
 	MATCH_END_ONLY,
+	MATCH_GLOB,
 };
 
 struct regex {
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 9daa9b3..e1c7e2c 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -344,6 +344,12 @@ static int regex_match_end(char *str, struct regex *r, int len)
 	return 0;
 }
 
+static int regex_match_glob(char *str, struct regex *r, int len __maybe_unused)
+{
+	if (glob_match(r->pattern, str))
+		return 1;
+	return 0;
+}
 /**
  * filter_parse_regex - parse a basic regex
  * @buff:   the raw regex
@@ -380,14 +386,20 @@ enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not)
 			if (!i) {
 				*search = buff + 1;
 				type = MATCH_END_ONLY;
-			} else {
+			} else if (i == len - 1) {
 				if (type == MATCH_END_ONLY)
 					type = MATCH_MIDDLE_ONLY;
 				else
 					type = MATCH_FRONT_ONLY;
 				buff[i] = 0;
 				break;
+			} else {	/* pattern continues, use full glob */
+				type = MATCH_GLOB;
+				break;
 			}
+		} else if (strchr("[?\\", buff[i])) {
+			type = MATCH_GLOB;
+			break;
 		}
 	}
 
@@ -420,6 +432,9 @@ static void filter_build_regex(struct filter_pred *pred)
 	case MATCH_END_ONLY:
 		r->match = regex_match_end;
 		break;
+	case MATCH_GLOB:
+		r->match = regex_match_glob;
+		break;
 	}
 
 	pred->not ^= not;

Re: [PATCH] ftrace: Support full glob matching

[Steven Rostedt]

On Wed,  5 Oct 2016 20:58:15 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> Use glob_match() to support flexible glob wildcards (*,?)
> and character classes ([) for ftrace.
> Since the full glob matching is slower than the current
> partial matching routines(*pat, pat*, *pat*), this leaves
> those routines and just add MATCH_GLOB for complex glob
> expression.
> 
> e.g.
> ----
> [root@localhost tracing]# echo 'sched*group' > set_ftrace_filter
> [root@localhost tracing]# cat set_ftrace_filter
> sched_free_group
> sched_change_group
> sched_create_group
> sched_online_group
> sched_destroy_group
> sched_offline_group
> [root@localhost tracing]# echo '[Ss]y[Ss]_*' > set_ftrace_filter
> [root@localhost tracing]# head set_ftrace_filter
> sys_arch_prctl
> sys_rt_sigreturn
> sys_ioperm
> SyS_iopl
> sys_modify_ldt
> SyS_mmap
> SyS_set_thread_area
> SyS_get_thread_area
> SyS_set_tid_address
> sys_fork
> ----
> 
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>

Nice! Although, I probably wont get to look at this till I get back
from Berlin. Please send me a friendly "ping" on the 17th.

I'll still add it to my new "todo" folder. Since, just marking patches
in my inbox as todo hasn't been working out for me, I've created a
separate folder for ftrace patches.

Thanks!

-- Steve

Re: [PATCH] ftrace: Support full glob matching

[Namhyung Kim]

Hi Masami,

On Wed, Oct 05, 2016 at 08:58:15PM +0900, Masami Hiramatsu wrote:
> Use glob_match() to support flexible glob wildcards (*,?)
> and character classes ([) for ftrace.
> Since the full glob matching is slower than the current
> partial matching routines(*pat, pat*, *pat*), this leaves
> those routines and just add MATCH_GLOB for complex glob
> expression.
> 
> e.g.
> ----
> [root@localhost tracing]# echo 'sched*group' > set_ftrace_filter
> [root@localhost tracing]# cat set_ftrace_filter
> sched_free_group
> sched_change_group
> sched_create_group
> sched_online_group
> sched_destroy_group
> sched_offline_group
> [root@localhost tracing]# echo '[Ss]y[Ss]_*' > set_ftrace_filter
> [root@localhost tracing]# head set_ftrace_filter
> sys_arch_prctl
> sys_rt_sigreturn
> sys_ioperm
> SyS_iopl
> sys_modify_ldt
> SyS_mmap
> SyS_set_thread_area
> SyS_get_thread_area
> SyS_set_tid_address
> sys_fork
> ----
> 
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>

Nice!

Acked-by: Namhyung Kim <namhyung@kernel.org>

Thanks,
Namhyung


> ---
>  Documentation/trace/events.txt     |    9 +++------
>  Documentation/trace/ftrace.txt     |    9 +++------
>  kernel/trace/Kconfig               |    2 ++
>  kernel/trace/ftrace.c              |    4 ++++
>  kernel/trace/trace.c               |    2 +-
>  kernel/trace/trace.h               |    2 ++
>  kernel/trace/trace_events_filter.c |   17 ++++++++++++++++-
>  7 files changed, 31 insertions(+), 14 deletions(-)
> 
> diff --git a/Documentation/trace/events.txt b/Documentation/trace/events.txt
> index 08d74d7..2cc08d4 100644
> --- a/Documentation/trace/events.txt
> +++ b/Documentation/trace/events.txt
> @@ -189,16 +189,13 @@ And for string fields they are:
>  
>  ==, !=, ~
>  
> -The glob (~) only accepts a wild card character (*) at the start and or
> -end of the string. For example:
> +The glob (~) accepts a wild card character (*,?) and character classes
> +([). For example:
>  
>    prev_comm ~ "*sh"
>    prev_comm ~ "sh*"
>    prev_comm ~ "*sh*"
> -
> -But does not allow for it to be within the string:
> -
> -  prev_comm ~ "ba*sh"   <-- is invalid
> +  prev_comm ~ "ba*sh"
>  
>  5.2 Setting filters
>  -------------------
> diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
> index a6b3705..b26abc7 100644
> --- a/Documentation/trace/ftrace.txt
> +++ b/Documentation/trace/ftrace.txt
> @@ -2218,16 +2218,13 @@ hrtimer_interrupt
>  sys_nanosleep
>  
>  
> -Perhaps this is not enough. The filters also allow simple wild
> -cards. Only the following are currently available
> +Perhaps this is not enough. The filters also allow glob(7) matching.
>  
>    <match>*  - will match functions that begin with <match>
>    *<match>  - will match functions that end with <match>
>    *<match>* - will match functions that have <match> in it
> -
> -These are the only wild cards which are supported.
> -
> -  <match>*<match> will not work.
> +  <match1>*<match2> - will match functions that begin with
> +                      <match1> and end with <match2>
>  
>  Note: It is better to use quotes to enclose the wild cards,
>        otherwise the shell may expand the parameters into names
> diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
> index ba33267..aa6eb15 100644
> --- a/kernel/trace/Kconfig
> +++ b/kernel/trace/Kconfig
> @@ -70,6 +70,7 @@ config FTRACE_NMI_ENTER
>  
>  config EVENT_TRACING
>  	select CONTEXT_SWITCH_TRACER
> +        select GLOB
>  	bool
>  
>  config CONTEXT_SWITCH_TRACER
> @@ -133,6 +134,7 @@ config FUNCTION_TRACER
>  	select KALLSYMS
>  	select GENERIC_TRACER
>  	select CONTEXT_SWITCH_TRACER
> +        select GLOB
>  	help
>  	  Enable the kernel to trace every kernel function. This is done
>  	  by using a compiler feature to insert a small, 5-byte No-Operation
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index 84752c8..5741184 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -3493,6 +3493,10 @@ static int ftrace_match(char *str, struct ftrace_glob *g)
>  		    memcmp(str + slen - g->len, g->search, g->len) == 0)
>  			matched = 1;
>  		break;
> +	case MATCH_GLOB:
> +		if (glob_match(g->search, str))
> +			matched = 1;
> +		break;
>  	}
>  
>  	return matched;
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 37824d9..ae343e7 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -4065,7 +4065,7 @@ static const char readme_msg[] =
>  	"\n  available_filter_functions - list of functions that can be filtered on\n"
>  	"  set_ftrace_filter\t- echo function name in here to only trace these\n"
>  	"\t\t\t  functions\n"
> -	"\t     accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
> +	"\t     accepts: func_full_name or glob-matching-pattern\n"
>  	"\t     modules: Can select a group via module\n"
>  	"\t      Format: :mod:<module-name>\n"
>  	"\t     example: echo :mod:ext3 > set_ftrace_filter\n"
> diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
> index f783df4..eac2eda 100644
> --- a/kernel/trace/trace.h
> +++ b/kernel/trace/trace.h
> @@ -15,6 +15,7 @@
>  #include <linux/trace_events.h>
>  #include <linux/compiler.h>
>  #include <linux/trace_seq.h>
> +#include <linux/glob.h>
>  
>  #ifdef CONFIG_FTRACE_SYSCALLS
>  #include <asm/unistd.h>		/* For NR_SYSCALLS	     */
> @@ -1252,6 +1253,7 @@ enum regex_type {
>  	MATCH_FRONT_ONLY,
>  	MATCH_MIDDLE_ONLY,
>  	MATCH_END_ONLY,
> +	MATCH_GLOB,
>  };
>  
>  struct regex {
> diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
> index 9daa9b3..e1c7e2c 100644
> --- a/kernel/trace/trace_events_filter.c
> +++ b/kernel/trace/trace_events_filter.c
> @@ -344,6 +344,12 @@ static int regex_match_end(char *str, struct regex *r, int len)
>  	return 0;
>  }
>  
> +static int regex_match_glob(char *str, struct regex *r, int len __maybe_unused)
> +{
> +	if (glob_match(r->pattern, str))
> +		return 1;
> +	return 0;
> +}
>  /**
>   * filter_parse_regex - parse a basic regex
>   * @buff:   the raw regex
> @@ -380,14 +386,20 @@ enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not)
>  			if (!i) {
>  				*search = buff + 1;
>  				type = MATCH_END_ONLY;
> -			} else {
> +			} else if (i == len - 1) {
>  				if (type == MATCH_END_ONLY)
>  					type = MATCH_MIDDLE_ONLY;
>  				else
>  					type = MATCH_FRONT_ONLY;
>  				buff[i] = 0;
>  				break;
> +			} else {	/* pattern continues, use full glob */
> +				type = MATCH_GLOB;
> +				break;
>  			}
> +		} else if (strchr("[?\\", buff[i])) {
> +			type = MATCH_GLOB;
> +			break;
>  		}
>  	}
>  
> @@ -420,6 +432,9 @@ static void filter_build_regex(struct filter_pred *pred)
>  	case MATCH_END_ONLY:
>  		r->match = regex_match_end;
>  		break;
> +	case MATCH_GLOB:
> +		r->match = regex_match_glob;
> +		break;
>  	}
>  
>  	pred->not ^= not;
> 

Re: [PATCH] ftrace: Support full glob matching

[Masami Hiramatsu]

On Wed, 5 Oct 2016 09:36:35 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:

> On Wed,  5 Oct 2016 20:58:15 +0900
> Masami Hiramatsu <mhiramat@kernel.org> wrote:
> 
> > Use glob_match() to support flexible glob wildcards (*,?)
> > and character classes ([) for ftrace.
> > Since the full glob matching is slower than the current
> > partial matching routines(*pat, pat*, *pat*), this leaves
> > those routines and just add MATCH_GLOB for complex glob
> > expression.
> > 
> > e.g.
> > ----
> > [root@localhost tracing]# echo 'sched*group' > set_ftrace_filter
> > [root@localhost tracing]# cat set_ftrace_filter
> > sched_free_group
> > sched_change_group
> > sched_create_group
> > sched_online_group
> > sched_destroy_group
> > sched_offline_group
> > [root@localhost tracing]# echo '[Ss]y[Ss]_*' > set_ftrace_filter
> > [root@localhost tracing]# head set_ftrace_filter
> > sys_arch_prctl
> > sys_rt_sigreturn
> > sys_ioperm
> > SyS_iopl
> > sys_modify_ldt
> > SyS_mmap
> > SyS_set_thread_area
> > SyS_get_thread_area
> > SyS_set_tid_address
> > sys_fork
> > ----
> > 
> > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> 
> Nice! Although, I probably wont get to look at this till I get back
> from Berlin. Please send me a friendly "ping" on the 17th.

OK, I'm also considering update ftracetest too for recent features.
Maybe I would better make a series including this.

> I'll still add it to my new "todo" folder. Since, just marking patches
> in my inbox as todo hasn't been working out for me, I've created a
> separate folder for ftrace patches.

:)

Thanks!

> 
> Thanks!
> 
> -- Steve


-- 
Masami Hiramatsu <mhiramat@kernel.org>

Re: [PATCH] ftrace: Support full glob matching

[Steven Rostedt]

Shuah,

Hi! I'm going to be pulling these patches into my tree, but since they
touch selftests, can you take a look at them. They were posted to LKML,
but if you need me to bounce them to you too, I can do that as well.

Here's the links of the patches with the selftests:

http://lkml.kernel.org/r/147685282642.8760.554191165644931816.stgit@devbox
http://lkml.kernel.org/r/147685283587.8760.2601950190140526395.stgit@devbox
http://lkml.kernel.org/r/147685284503.8760.3870499047839781698.stgit@devbox
http://lkml.kernel.org/r/147685285432.8760.9114124487704649863.stgit@devbox

I'm still in the process of reviewing them myself.

-- Steve


On Wed,  5 Oct 2016 20:58:15 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:

> Use glob_match() to support flexible glob wildcards (*,?)
> and character classes ([) for ftrace.
> Since the full glob matching is slower than the current
> partial matching routines(*pat, pat*, *pat*), this leaves
> those routines and just add MATCH_GLOB for complex glob
> expression.
> 
> e.g.
> ----
> [root@localhost tracing]# echo 'sched*group' > set_ftrace_filter
> [root@localhost tracing]# cat set_ftrace_filter
> sched_free_group
> sched_change_group
> sched_create_group
> sched_online_group
> sched_destroy_group
> sched_offline_group
> [root@localhost tracing]# echo '[Ss]y[Ss]_*' > set_ftrace_filter
> [root@localhost tracing]# head set_ftrace_filter
> sys_arch_prctl
> sys_rt_sigreturn
> sys_ioperm
> SyS_iopl
> sys_modify_ldt
> SyS_mmap
> SyS_set_thread_area
> SyS_get_thread_area
> SyS_set_tid_address
> sys_fork
> ----
> 
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> ---
>  Documentation/trace/events.txt     |    9 +++------
>  Documentation/trace/ftrace.txt     |    9 +++------
>  kernel/trace/Kconfig               |    2 ++
>  kernel/trace/ftrace.c              |    4 ++++
>  kernel/trace/trace.c               |    2 +-
>  kernel/trace/trace.h               |    2 ++
>  kernel/trace/trace_events_filter.c |   17 ++++++++++++++++-
>  7 files changed, 31 insertions(+), 14 deletions(-)
> 
> diff --git a/Documentation/trace/events.txt b/Documentation/trace/events.txt
> index 08d74d7..2cc08d4 100644
> --- a/Documentation/trace/events.txt
> +++ b/Documentation/trace/events.txt
> @@ -189,16 +189,13 @@ And for string fields they are:
>  
>  ==, !=, ~
>  
> -The glob (~) only accepts a wild card character (*) at the start and or
> -end of the string. For example:
> +The glob (~) accepts a wild card character (*,?) and character classes
> +([). For example:
>  
>    prev_comm ~ "*sh"
>    prev_comm ~ "sh*"
>    prev_comm ~ "*sh*"
> -
> -But does not allow for it to be within the string:
> -
> -  prev_comm ~ "ba*sh"   <-- is invalid
> +  prev_comm ~ "ba*sh"
>  
>  5.2 Setting filters
>  -------------------
> diff --git a/Documentation/trace/ftrace.txt b/Documentation/trace/ftrace.txt
> index a6b3705..b26abc7 100644
> --- a/Documentation/trace/ftrace.txt
> +++ b/Documentation/trace/ftrace.txt
> @@ -2218,16 +2218,13 @@ hrtimer_interrupt
>  sys_nanosleep
>  
>  
> -Perhaps this is not enough. The filters also allow simple wild
> -cards. Only the following are currently available
> +Perhaps this is not enough. The filters also allow glob(7) matching.
>  
>    <match>*  - will match functions that begin with <match>
>    *<match>  - will match functions that end with <match>
>    *<match>* - will match functions that have <match> in it
> -
> -These are the only wild cards which are supported.
> -
> -  <match>*<match> will not work.
> +  <match1>*<match2> - will match functions that begin with
> +                      <match1> and end with <match2>
>  
>  Note: It is better to use quotes to enclose the wild cards,
>        otherwise the shell may expand the parameters into names
> diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
> index ba33267..aa6eb15 100644
> --- a/kernel/trace/Kconfig
> +++ b/kernel/trace/Kconfig
> @@ -70,6 +70,7 @@ config FTRACE_NMI_ENTER
>  
>  config EVENT_TRACING
>  	select CONTEXT_SWITCH_TRACER
> +        select GLOB
>  	bool
>  
>  config CONTEXT_SWITCH_TRACER
> @@ -133,6 +134,7 @@ config FUNCTION_TRACER
>  	select KALLSYMS
>  	select GENERIC_TRACER
>  	select CONTEXT_SWITCH_TRACER
> +        select GLOB
>  	help
>  	  Enable the kernel to trace every kernel function. This is done
>  	  by using a compiler feature to insert a small, 5-byte No-Operation
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index 84752c8..5741184 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -3493,6 +3493,10 @@ static int ftrace_match(char *str, struct ftrace_glob *g)
>  		    memcmp(str + slen - g->len, g->search, g->len) == 0)
>  			matched = 1;
>  		break;
> +	case MATCH_GLOB:
> +		if (glob_match(g->search, str))
> +			matched = 1;
> +		break;
>  	}
>  
>  	return matched;
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index 37824d9..ae343e7 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -4065,7 +4065,7 @@ static const char readme_msg[] =
>  	"\n  available_filter_functions - list of functions that can be filtered on\n"
>  	"  set_ftrace_filter\t- echo function name in here to only trace these\n"
>  	"\t\t\t  functions\n"
> -	"\t     accepts: func_full_name, *func_end, func_begin*, *func_middle*\n"
> +	"\t     accepts: func_full_name or glob-matching-pattern\n"
>  	"\t     modules: Can select a group via module\n"
>  	"\t      Format: :mod:<module-name>\n"
>  	"\t     example: echo :mod:ext3 > set_ftrace_filter\n"
> diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
> index f783df4..eac2eda 100644
> --- a/kernel/trace/trace.h
> +++ b/kernel/trace/trace.h
> @@ -15,6 +15,7 @@
>  #include <linux/trace_events.h>
>  #include <linux/compiler.h>
>  #include <linux/trace_seq.h>
> +#include <linux/glob.h>
>  
>  #ifdef CONFIG_FTRACE_SYSCALLS
>  #include <asm/unistd.h>		/* For NR_SYSCALLS	     */
> @@ -1252,6 +1253,7 @@ enum regex_type {
>  	MATCH_FRONT_ONLY,
>  	MATCH_MIDDLE_ONLY,
>  	MATCH_END_ONLY,
> +	MATCH_GLOB,
>  };
>  
>  struct regex {
> diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
> index 9daa9b3..e1c7e2c 100644
> --- a/kernel/trace/trace_events_filter.c
> +++ b/kernel/trace/trace_events_filter.c
> @@ -344,6 +344,12 @@ static int regex_match_end(char *str, struct regex *r, int len)
>  	return 0;
>  }
>  
> +static int regex_match_glob(char *str, struct regex *r, int len __maybe_unused)
> +{
> +	if (glob_match(r->pattern, str))
> +		return 1;
> +	return 0;
> +}
>  /**
>   * filter_parse_regex - parse a basic regex
>   * @buff:   the raw regex
> @@ -380,14 +386,20 @@ enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not)
>  			if (!i) {
>  				*search = buff + 1;
>  				type = MATCH_END_ONLY;
> -			} else {
> +			} else if (i == len - 1) {
>  				if (type == MATCH_END_ONLY)
>  					type = MATCH_MIDDLE_ONLY;
>  				else
>  					type = MATCH_FRONT_ONLY;
>  				buff[i] = 0;
>  				break;
> +			} else {	/* pattern continues, use full glob */
> +				type = MATCH_GLOB;
> +				break;
>  			}
> +		} else if (strchr("[?\\", buff[i])) {
> +			type = MATCH_GLOB;
> +			break;
>  		}
>  	}
>  
> @@ -420,6 +432,9 @@ static void filter_build_regex(struct filter_pred *pred)
>  	case MATCH_END_ONLY:
>  		r->match = regex_match_end;
>  		break;
> +	case MATCH_GLOB:
> +		r->match = regex_match_glob;
> +		break;
>  	}
>  
>  	pred->not ^= not;