From: Masami Hiramatsu (Google) <[email protected]>
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 <[email protected]>
Closes: https://lore.kernel.org/all/[email protected]/
Signed-off-by: Masami Hiramatsu (Google) <[email protected]>
---
include/linux/tracepoint.h | 7 +++++++
kernel/trace/trace_fprobe.c | 46 ++++++++++++++++++++++++++++++++++++-------
kernel/tracepoint.c | 19 ++++++++++++++++++
3 files changed, 64 insertions(+), 8 deletions(-)
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 */
/**
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/[email protected]/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/[email protected]/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 <[email protected]>
| Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
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
On Sat, 1 Jun 2024 01:01:26 +0800
kernel test robot <[email protected]> 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/[email protected]/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/[email protected]/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 <[email protected]>
> | Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
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
--
Masami Hiramatsu (Google) <[email protected]>