diff mbox series

tracing/fprobe: Support raw tracepoint events on modules

Message ID 171714888633.198965.13093663631481169611.stgit@devnote2 (mailing list archive)
State Changes Requested
Delegated to: Masami Hiramatsu
Headers show
Series tracing/fprobe: Support raw tracepoint events on modules | expand

Commit Message

Masami Hiramatsu (Google) May 31, 2024, 9:48 a.m. UTC 
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

Support raw tracepoint event on module by fprobe events.
Since it only uses for_each_kernel_tracepoint() to find a tracepoint,
the tracepoints on modules are not handled. Thus if user specified a
tracepoint on a module, it shows an error.
This adds new for_each_module_tracepoint() API to tracepoint subsystem,
and uses it to find tracepoints on modules.

Reported-by: don <zds100@gmail.com>
Closes: https://lore.kernel.org/all/20240530215718.aeec973a1d0bf058d39cb1e3@kernel.org/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 include/linux/tracepoint.h  |    7 +++++++
 kernel/trace/trace_fprobe.c |   46 ++++++++++++++++++++++++++++++++++++-------
 kernel/tracepoint.c         |   19 ++++++++++++++++++
 3 files changed, 64 insertions(+), 8 deletions(-)

Comments

kernel test robot May 31, 2024, 5:01 p.m. UTC | #1 
Hi Masami,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on v6.10-rc1 next-20240531]
[cannot apply to rostedt-trace/for-next rostedt-trace/for-next-urgent]
[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/Masami-Hiramatsu-Google/tracing-fprobe-Support-raw-tracepoint-events-on-modules/20240531-175013
base:   linus/master
patch link:    https://lore.kernel.org/r/171714888633.198965.13093663631481169611.stgit%40devnote2
patch subject: [PATCH] tracing/fprobe: Support raw tracepoint events on modules
config: s390-defconfig (https://download.01.org/0day-ci/archive/20240601/202406010034.fsNP9Rsq-lkp@intel.com/config)
compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project bafda89a0944d947fc4b3b5663185e07a397ac30)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240601/202406010034.fsNP9Rsq-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/202406010034.fsNP9Rsq-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from kernel/tracepoint.c:5:
   In file included from include/linux/module.h:19:
   In file included from include/linux/elf.h:6:
   In file included from arch/s390/include/asm/elf.h:173:
   In file included from arch/s390/include/asm/mmu_context.h:11:
   In file included from arch/s390/include/asm/pgalloc.h:18:
   In file included from include/linux/mm.h:2253:
   include/linux/vmstat.h:500:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     500 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     501 |                            item];
         |                            ~~~~
   include/linux/vmstat.h:507:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     507 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     508 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
   include/linux/vmstat.h:514:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     514 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
   include/linux/vmstat.h:519:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     519 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     520 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
   include/linux/vmstat.h:528:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
     528 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~ ^
     529 |                            NR_VM_NUMA_EVENT_ITEMS +
         |                            ~~~~~~~~~~~~~~~~~~~~~~
>> kernel/tracepoint.c:751:34: error: no member named '__start___tracepoints_ptrs' in 'struct module'
     751 |                 for_each_tracepoint_range(mod->__start___tracepoints_ptrs,
         |                                           ~~~  ^
   5 warnings and 1 error generated.


vim +751 kernel/tracepoint.c

   738	
   739	void for_each_module_tracepoint(void (*fct)(struct tracepoint *tp, void *priv),
   740					void *priv)
   741	{
   742		struct tp_module *tp_mod;
   743		struct module *mod;
   744	
   745		if (!mod->num_tracepoints)
   746			return;
   747	
   748		mutex_lock(&tracepoint_module_list_mutex);
   749		list_for_each_entry(tp_mod, &tracepoint_module_list, list) {
   750			mod = tp_mod->mod;
 > 751			for_each_tracepoint_range(mod->__start___tracepoints_ptrs,
   752				mod->tracepoints_ptrs + mod->num_tracepoints,
   753				fct, priv);
   754		}
   755		mutex_unlock(&tracepoint_module_list_mutex);
   756	}
   757	#endif /* CONFIG_MODULES */
   758
Masami Hiramatsu (Google) June 1, 2024, 1:35 a.m. UTC | #2 
On Sat, 1 Jun 2024 01:01:26 +0800
kernel test robot <lkp@intel.com> wrote:

> Hi Masami,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on linus/master]
> [also build test ERROR on v6.10-rc1 next-20240531]
> [cannot apply to rostedt-trace/for-next rostedt-trace/for-next-urgent]
> [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/Masami-Hiramatsu-Google/tracing-fprobe-Support-raw-tracepoint-events-on-modules/20240531-175013
> base:   linus/master
> patch link:    https://lore.kernel.org/r/171714888633.198965.13093663631481169611.stgit%40devnote2
> patch subject: [PATCH] tracing/fprobe: Support raw tracepoint events on modules
> config: s390-defconfig (https://download.01.org/0day-ci/archive/20240601/202406010034.fsNP9Rsq-lkp@intel.com/config)
> compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project bafda89a0944d947fc4b3b5663185e07a397ac30)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240601/202406010034.fsNP9Rsq-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/202406010034.fsNP9Rsq-lkp@intel.com/

OK, I must be tired... let me fix that. And I'll add a selftest for this case.

Thanks!

> 
> All errors (new ones prefixed by >>):
> 
>    In file included from kernel/tracepoint.c:5:
>    In file included from include/linux/module.h:19:
>    In file included from include/linux/elf.h:6:
>    In file included from arch/s390/include/asm/elf.h:173:
>    In file included from arch/s390/include/asm/mmu_context.h:11:
>    In file included from arch/s390/include/asm/pgalloc.h:18:
>    In file included from include/linux/mm.h:2253:
>    include/linux/vmstat.h:500:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
>      500 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
>          |                            ~~~~~~~~~~~~~~~~~~~~~ ^
>      501 |                            item];
>          |                            ~~~~
>    include/linux/vmstat.h:507:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
>      507 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
>          |                            ~~~~~~~~~~~~~~~~~~~~~ ^
>      508 |                            NR_VM_NUMA_EVENT_ITEMS +
>          |                            ~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/vmstat.h:514:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
>      514 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
>          |                               ~~~~~~~~~~~ ^ ~~~
>    include/linux/vmstat.h:519:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
>      519 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
>          |                            ~~~~~~~~~~~~~~~~~~~~~ ^
>      520 |                            NR_VM_NUMA_EVENT_ITEMS +
>          |                            ~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/vmstat.h:528:43: warning: arithmetic between different enumeration types ('enum zone_stat_item' and 'enum numa_stat_item') [-Wenum-enum-conversion]
>      528 |         return vmstat_text[NR_VM_ZONE_STAT_ITEMS +
>          |                            ~~~~~~~~~~~~~~~~~~~~~ ^
>      529 |                            NR_VM_NUMA_EVENT_ITEMS +
>          |                            ~~~~~~~~~~~~~~~~~~~~~~
> >> kernel/tracepoint.c:751:34: error: no member named '__start___tracepoints_ptrs' in 'struct module'
>      751 |                 for_each_tracepoint_range(mod->__start___tracepoints_ptrs,
>          |                                           ~~~  ^
>    5 warnings and 1 error generated.
> 
> 
> vim +751 kernel/tracepoint.c
> 
>    738	
>    739	void for_each_module_tracepoint(void (*fct)(struct tracepoint *tp, void *priv),
>    740					void *priv)
>    741	{
>    742		struct tp_module *tp_mod;
>    743		struct module *mod;
>    744	
>    745		if (!mod->num_tracepoints)
>    746			return;
>    747	
>    748		mutex_lock(&tracepoint_module_list_mutex);
>    749		list_for_each_entry(tp_mod, &tracepoint_module_list, list) {
>    750			mod = tp_mod->mod;
>  > 751			for_each_tracepoint_range(mod->__start___tracepoints_ptrs,
>    752				mod->tracepoints_ptrs + mod->num_tracepoints,
>    753				fct, priv);
>    754		}
>    755		mutex_unlock(&tracepoint_module_list_mutex);
>    756	}
>    757	#endif /* CONFIG_MODULES */
>    758	
> 
> -- 
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
diff mbox series

Patch

diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 689b6d71590e..46e6a5e759fd 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -65,6 +65,8 @@  struct tp_module {
 bool trace_module_has_bad_taint(struct module *mod);
 extern int register_tracepoint_module_notifier(struct notifier_block *nb);
 extern int unregister_tracepoint_module_notifier(struct notifier_block *nb);
+void for_each_module_tracepoint(void (*fct)(struct tracepoint *, void *),
+				void *priv);
 #else
 static inline bool trace_module_has_bad_taint(struct module *mod)
 {
@@ -80,6 +82,11 @@  int unregister_tracepoint_module_notifier(struct notifier_block *nb)
 {
 	return 0;
 }
+static inline
+void for_each_module_tracepoint(void (*fct)(struct tracepoint *, void *),
+				void *priv)
+{
+}
 #endif /* CONFIG_MODULES */
 
 /*
diff --git a/kernel/trace/trace_fprobe.c b/kernel/trace/trace_fprobe.c
index 62e6a8f4aae9..1d8a983e1edc 100644
--- a/kernel/trace/trace_fprobe.c
+++ b/kernel/trace/trace_fprobe.c
@@ -385,6 +385,7 @@  static struct trace_fprobe *alloc_trace_fprobe(const char *group,
 					       const char *event,
 					       const char *symbol,
 					       struct tracepoint *tpoint,
+					       struct module *mod,
 					       int maxactive,
 					       int nargs, bool is_return)
 {
@@ -405,6 +406,7 @@  static struct trace_fprobe *alloc_trace_fprobe(const char *group,
 		tf->fp.entry_handler = fentry_dispatcher;
 
 	tf->tpoint = tpoint;
+	tf->mod = mod;
 	tf->fp.nr_maxactive = maxactive;
 
 	ret = trace_probe_init(&tf->tp, event, group, false, nargs);
@@ -895,8 +897,23 @@  static struct notifier_block tracepoint_module_nb = {
 struct __find_tracepoint_cb_data {
 	const char *tp_name;
 	struct tracepoint *tpoint;
+	struct module *mod;
 };
 
+static void __find_tracepoint_module_cb(struct tracepoint *tp, void *priv)
+{
+	struct __find_tracepoint_cb_data *data = priv;
+
+	if (!data->tpoint && !strcmp(data->tp_name, tp->name)) {
+		data->tpoint = tp;
+		data->mod = __module_text_address((unsigned long)tp->probestub);
+		if (!try_module_get(data->mod)) {
+			data->tpoint = NULL;
+			data->mod = NULL;
+		}
+	}
+}
+
 static void __find_tracepoint_cb(struct tracepoint *tp, void *priv)
 {
 	struct __find_tracepoint_cb_data *data = priv;
@@ -905,14 +922,28 @@  static void __find_tracepoint_cb(struct tracepoint *tp, void *priv)
 		data->tpoint = tp;
 }
 
-static struct tracepoint *find_tracepoint(const char *tp_name)
+/*
+ * Find a tracepoint from kernel and module. If the tracepoint is in a module,
+ * this increments the module refcount to prevent unloading until the
+ * trace_fprobe is registered to the list. After registering the trace_fprobe
+ * on the trace_fprobe list, the module refcount is decremented because
+ * tracepoint_probe_module_cb will handle it.
+ */
+static struct tracepoint *find_tracepoint(const char *tp_name,
+					  struct module **tp_mod)
 {
 	struct __find_tracepoint_cb_data data = {
 		.tp_name = tp_name,
+		.mod = NULL,
 	};
 
 	for_each_kernel_tracepoint(__find_tracepoint_cb, &data);
 
+	if (!data.tpoint && IS_ENABLED(CONFIG_MODULES)) {
+		for_each_module_tracepoint(__find_tracepoint_module_cb, &data);
+		*tp_mod = data.mod;
+	}
+
 	return data.tpoint;
 }
 
@@ -996,6 +1027,7 @@  static int __trace_fprobe_create(int argc, const char *argv[])
 	char abuf[MAX_BTF_ARGS_LEN];
 	char *dbuf = NULL;
 	bool is_tracepoint = false;
+	struct module *tp_mod = NULL;
 	struct tracepoint *tpoint = NULL;
 	struct traceprobe_parse_context ctx = {
 		.flags = TPARG_FL_KERNEL | TPARG_FL_FPROBE,
@@ -1080,7 +1112,7 @@  static int __trace_fprobe_create(int argc, const char *argv[])
 
 	if (is_tracepoint) {
 		ctx.flags |= TPARG_FL_TPOINT;
-		tpoint = find_tracepoint(symbol);
+		tpoint = find_tracepoint(symbol, &tp_mod);
 		if (!tpoint) {
 			trace_probe_log_set_index(1);
 			trace_probe_log_err(0, NO_TRACEPOINT);
@@ -1110,8 +1142,8 @@  static int __trace_fprobe_create(int argc, const char *argv[])
 		goto out;
 
 	/* setup a probe */
-	tf = alloc_trace_fprobe(group, event, symbol, tpoint, maxactive,
-				argc, is_return);
+	tf = alloc_trace_fprobe(group, event, symbol, tpoint, tp_mod,
+				maxactive, argc, is_return);
 	if (IS_ERR(tf)) {
 		ret = PTR_ERR(tf);
 		/* This must return -ENOMEM, else there is a bug */
@@ -1119,10 +1151,6 @@  static int __trace_fprobe_create(int argc, const char *argv[])
 		goto out;	/* We know tf is not allocated */
 	}
 
-	if (is_tracepoint)
-		tf->mod = __module_text_address(
-				(unsigned long)tf->tpoint->probestub);
-
 	/* parse arguments */
 	for (i = 0; i < argc && i < MAX_TRACE_ARGS; i++) {
 		trace_probe_log_set_index(i + 2);
@@ -1155,6 +1183,8 @@  static int __trace_fprobe_create(int argc, const char *argv[])
 	}
 
 out:
+	if (tp_mod)
+		module_put(tp_mod);
 	traceprobe_finish_parse(&ctx);
 	trace_probe_log_clear();
 	kfree(new_argv);
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 8d1507dd0724..981b60199413 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -735,6 +735,25 @@  static __init int init_tracepoints(void)
 	return ret;
 }
 __initcall(init_tracepoints);
+
+void for_each_module_tracepoint(void (*fct)(struct tracepoint *tp, void *priv),
+				void *priv)
+{
+	struct tp_module *tp_mod;
+	struct module *mod;
+
+	if (!mod->num_tracepoints)
+		return;
+
+	mutex_lock(&tracepoint_module_list_mutex);
+	list_for_each_entry(tp_mod, &tracepoint_module_list, list) {
+		mod = tp_mod->mod;
+		for_each_tracepoint_range(mod->__start___tracepoints_ptrs,
+			mod->tracepoints_ptrs + mod->num_tracepoints,
+			fct, priv);
+	}
+	mutex_unlock(&tracepoint_module_list_mutex);
+}
 #endif /* CONFIG_MODULES */
 
 /**