| Message ID | 20240123110757.3657908-4-vdonnefort@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Introducing trace buffer mapping by user-space | expand |
On Tue, 23 Jan 2024 11:07:54 +0000 Vincent Donnefort <vdonnefort@google.com> wrote: [...] > @@ -6592,8 +6641,11 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) > > if (t->init) { > ret = tracer_init(t, tr); > - if (ret) > + if (ret) { > + if (t->use_max_tr) > + tracing_disarm_snapshot_locked(tr); This part is out of CONFIG_TRACER_MAX_TRACE, so it may cause a compile error if CONFIG_TRACER_MAX_TRACE is not set. > goto out; > + } > } > > tr->current_trace = t; [...] > diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c > index 46439e3bcec4..d41bf64741e2 100644 > --- a/kernel/trace/trace_events_trigger.c > +++ b/kernel/trace/trace_events_trigger.c > @@ -597,20 +597,9 @@ static int register_trigger(char *glob, > return ret; > } > > -/** > - * unregister_trigger - Generic event_command @unreg implementation > - * @glob: The raw string used to register the trigger > - * @test: Trigger-specific data used to find the trigger to remove > - * @file: The trace_event_file associated with the event > - * > - * Common implementation for event trigger unregistration. > - * > - * Usually used directly as the @unreg method in event command > - * implementations. > - */ > -static void unregister_trigger(char *glob, > - struct event_trigger_data *test, > - struct trace_event_file *file) OK, so __unregister_trigger returns true if data exists, but unregister_trigger() ignores results. (I want some comment here) > +static bool __unregister_trigger(char *glob, > + struct event_trigger_data *test, > + struct trace_event_file *file) > { > struct event_trigger_data *data = NULL, *iter; > > @@ -626,8 +615,32 @@ static void unregister_trigger(char *glob, > } > } > > - if (data && data->ops->free) > - data->ops->free(data); > + if (data) { > + if (data->ops->free) > + data->ops->free(data); > + > + return true; > + } > + > + return false; > +} > + > +/** > + * unregister_trigger - Generic event_command @unreg implementation > + * @glob: The raw string used to register the trigger > + * @test: Trigger-specific data used to find the trigger to remove > + * @file: The trace_event_file associated with the event > + * > + * Common implementation for event trigger unregistration. > + * > + * Usually used directly as the @unreg method in event command > + * implementations. > + */ > +static void unregister_trigger(char *glob, > + struct event_trigger_data *test, > + struct trace_event_file *file) > +{ > + __unregister_trigger(glob, test, file); > } > > /* > @@ -1470,12 +1483,20 @@ register_snapshot_trigger(char *glob, > struct event_trigger_data *data, > struct trace_event_file *file) > { > - if (tracing_alloc_snapshot_instance(file->tr) != 0) > + if (tracing_arm_snapshot(file->tr)) > return 0; BTW, is this return value correct? It seems that the register_*_trigger() will return error code when it fails. Thanks, > > return register_trigger(glob, data, file); > } > > +static void unregister_snapshot_trigger(char *glob, > + struct event_trigger_data *data, > + struct trace_event_file *file) > +{ > + if (__unregister_trigger(glob, data, file)) > + tracing_disarm_snapshot(file->tr); > +} > + > static int > snapshot_trigger_print(struct seq_file *m, struct event_trigger_data *data) > { > @@ -1508,7 +1529,7 @@ static struct event_command trigger_snapshot_cmd = { > .trigger_type = ETT_SNAPSHOT, > .parse = event_trigger_parse, > .reg = register_snapshot_trigger, > - .unreg = unregister_trigger, > + .unreg = unregister_snapshot_trigger, > .get_trigger_ops = snapshot_get_trigger_ops, > .set_filter = set_trigger_filter, > }; > -- > 2.43.0.429.g432eaa2c6b-goog >
Hi Masami, Thanks for taking the time to look at those changes. On Thu, Jan 25, 2024 at 12:11:49AM +0900, Masami Hiramatsu wrote: > On Tue, 23 Jan 2024 11:07:54 +0000 > Vincent Donnefort <vdonnefort@google.com> wrote: > > [...] > > @@ -6592,8 +6641,11 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) > > > > if (t->init) { > > ret = tracer_init(t, tr); > > - if (ret) > > + if (ret) { > > + if (t->use_max_tr) > > + tracing_disarm_snapshot_locked(tr); > > This part is out of CONFIG_TRACER_MAX_TRACE, so it may cause a compile error > if CONFIG_TRACER_MAX_TRACE is not set. Duh, yes it must depends on TRACER_MAX_TRACE :-\ > > > goto out; > > + } > > } > > > > tr->current_trace = t; > [...] > > diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c > > index 46439e3bcec4..d41bf64741e2 100644 > > --- a/kernel/trace/trace_events_trigger.c > > +++ b/kernel/trace/trace_events_trigger.c > > @@ -597,20 +597,9 @@ static int register_trigger(char *glob, > > return ret; > > } > > > > -/** > > - * unregister_trigger - Generic event_command @unreg implementation > > - * @glob: The raw string used to register the trigger > > - * @test: Trigger-specific data used to find the trigger to remove > > - * @file: The trace_event_file associated with the event > > - * > > - * Common implementation for event trigger unregistration. > > - * > > - * Usually used directly as the @unreg method in event command > > - * implementations. > > - */ > > -static void unregister_trigger(char *glob, > > - struct event_trigger_data *test, > > - struct trace_event_file *file) > > OK, so __unregister_trigger returns true if data exists, but > unregister_trigger() ignores results. (I want some comment here) Will add something for the __unregister_trigger flavour. > > > +static bool __unregister_trigger(char *glob, > > + struct event_trigger_data *test, > > + struct trace_event_file *file) > > { > > struct event_trigger_data *data = NULL, *iter; > > > > @@ -626,8 +615,32 @@ static void unregister_trigger(char *glob, > > } > > } > > > > - if (data && data->ops->free) > > - data->ops->free(data); > > + if (data) { > > + if (data->ops->free) > > + data->ops->free(data); > > + > > + return true; > > + } > > + > > + return false; > > +} > > + > > +/** > > + * unregister_trigger - Generic event_command @unreg implementation > > + * @glob: The raw string used to register the trigger > > + * @test: Trigger-specific data used to find the trigger to remove > > + * @file: The trace_event_file associated with the event > > + * > > + * Common implementation for event trigger unregistration. > > + * > > + * Usually used directly as the @unreg method in event command > > + * implementations. > > + */ > > +static void unregister_trigger(char *glob, > > + struct event_trigger_data *test, > > + struct trace_event_file *file) > > +{ > > + __unregister_trigger(glob, test, file); > > } > > > > /* > > @@ -1470,12 +1483,20 @@ register_snapshot_trigger(char *glob, > > struct event_trigger_data *data, > > struct trace_event_file *file) > > { > > - if (tracing_alloc_snapshot_instance(file->tr) != 0) > > + if (tracing_arm_snapshot(file->tr)) > > return 0; > > BTW, is this return value correct? It seems that the register_*_trigger() > will return error code when it fails. It should indeed be ret = tracing_arm_snapshot() if (ret) return ret; > > Thanks, > > > > > return register_trigger(glob, data, file); > > } > > > > +static void unregister_snapshot_trigger(char *glob, > > + struct event_trigger_data *data, > > + struct trace_event_file *file) > > +{ > > + if (__unregister_trigger(glob, data, file)) > > + tracing_disarm_snapshot(file->tr); > > +} > > + > > static int > > snapshot_trigger_print(struct seq_file *m, struct event_trigger_data *data) > > { > > @@ -1508,7 +1529,7 @@ static struct event_command trigger_snapshot_cmd = { > > .trigger_type = ETT_SNAPSHOT, > > .parse = event_trigger_parse, > > .reg = register_snapshot_trigger, > > - .unreg = unregister_trigger, > > + .unreg = unregister_snapshot_trigger, > > .get_trigger_ops = snapshot_get_trigger_ops, > > .set_filter = set_trigger_filter, > > }; > > -- > > 2.43.0.429.g432eaa2c6b-goog > > > > > -- > Masami Hiramatsu (Google) <mhiramat@kernel.org>
Hi Vincent, On Thu, 25 Jan 2024 14:53:40 +0000 Vincent Donnefort <vdonnefort@google.com> wrote: > > > @@ -1470,12 +1483,20 @@ register_snapshot_trigger(char *glob, > > > struct event_trigger_data *data, > > > struct trace_event_file *file) > > > { > > > - if (tracing_alloc_snapshot_instance(file->tr) != 0) > > > + if (tracing_arm_snapshot(file->tr)) > > > return 0; > > > > BTW, is this return value correct? It seems that the register_*_trigger() > > will return error code when it fails. > > It should indeed be > > ret = tracing_arm_snapshot() > if (ret) > return ret; OK, then there is a bug. We need to fix it before changing this for backporting. Thank you,
Hi Vincent, kernel test robot noticed the following build errors: [auto build test ERROR on 4f1991a92cfe89096b2d1f5583a2e093bdd55c37] url: https://github.com/intel-lab-lkp/linux/commits/Vincent-Donnefort/ring-buffer-Zero-ring-buffer-sub-buffers/20240123-191131 base: 4f1991a92cfe89096b2d1f5583a2e093bdd55c37 patch link: https://lore.kernel.org/r/20240123110757.3657908-4-vdonnefort%40google.com patch subject: [PATCH v12 3/6] tracing: Add snapshot refcount config: i386-buildonly-randconfig-005-20240126 (https://download.01.org/0day-ci/archive/20240126/202401260918.sn23MDek-lkp@intel.com/config) compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18) reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240126/202401260918.sn23MDek-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/202401260918.sn23MDek-lkp@intel.com/ All errors (new ones prefixed by >>): >> kernel/trace/trace.c:6645:11: error: no member named 'use_max_tr' in 'struct tracer' 6645 | if (t->use_max_tr) | ~ ^ >> kernel/trace/trace.c:6646:5: error: call to undeclared function 'tracing_disarm_snapshot_locked'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration] 6646 | tracing_disarm_snapshot_locked(tr); | ^ kernel/trace/trace.c:6646:5: note: did you mean 'tracing_disarm_snapshot'? kernel/trace/trace.h:1986:20: note: 'tracing_disarm_snapshot' declared here 1986 | static inline void tracing_disarm_snapshot(struct trace_array *tr) { } | ^ 2 errors generated. vim +6645 kernel/trace/trace.c 6641 6642 if (t->init) { 6643 ret = tracer_init(t, tr); 6644 if (ret) { > 6645 if (t->use_max_tr) > 6646 tracing_disarm_snapshot_locked(tr); 6647 goto out; 6648 } 6649 } 6650 6651 tr->current_trace = t; 6652 tr->current_trace->enabled++; 6653 trace_branch_enable(tr); 6654 out: 6655 mutex_unlock(&trace_types_lock); 6656 6657 return ret; 6658 } 6659
Hi Vincent, kernel test robot noticed the following build errors: [auto build test ERROR on 4f1991a92cfe89096b2d1f5583a2e093bdd55c37] url: https://github.com/intel-lab-lkp/linux/commits/Vincent-Donnefort/ring-buffer-Zero-ring-buffer-sub-buffers/20240123-191131 base: 4f1991a92cfe89096b2d1f5583a2e093bdd55c37 patch link: https://lore.kernel.org/r/20240123110757.3657908-4-vdonnefort%40google.com patch subject: [PATCH v12 3/6] tracing: Add snapshot refcount config: i386-randconfig-012-20240126 (https://download.01.org/0day-ci/archive/20240126/202401261026.Cc8uBwxf-lkp@intel.com/config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240126/202401261026.Cc8uBwxf-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/202401261026.Cc8uBwxf-lkp@intel.com/ All errors (new ones prefixed by >>): kernel/trace/trace.c: In function 'tracing_set_tracer': >> kernel/trace/trace.c:6645:9: error: 'struct tracer' has no member named 'use_max_tr' 6645 | if (t->use_max_tr) | ^~ >> kernel/trace/trace.c:6646:5: error: implicit declaration of function 'tracing_disarm_snapshot_locked'; did you mean 'tracing_disarm_snapshot'? [-Werror=implicit-function-declaration] 6646 | tracing_disarm_snapshot_locked(tr); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | tracing_disarm_snapshot cc1: some warnings being treated as errors vim +6645 kernel/trace/trace.c 6641 6642 if (t->init) { 6643 ret = tracer_init(t, tr); 6644 if (ret) { > 6645 if (t->use_max_tr) > 6646 tracing_disarm_snapshot_locked(tr); 6647 goto out; 6648 } 6649 } 6650 6651 tr->current_trace = t; 6652 tr->current_trace->enabled++; 6653 trace_branch_enable(tr); 6654 out: 6655 mutex_unlock(&trace_types_lock); 6656 6657 return ret; 6658 } 6659
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 46dbe22121e9..ac59321a8d95 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -1300,6 +1300,52 @@ static void free_snapshot(struct trace_array *tr) tr->allocated_snapshot = false; } +static int tracing_arm_snapshot_locked(struct trace_array *tr) +{ + int ret; + + lockdep_assert_held(&trace_types_lock); + + if (tr->snapshot == UINT_MAX) + return -EBUSY; + + ret = tracing_alloc_snapshot_instance(tr); + if (ret) + return ret; + + tr->snapshot++; + + return 0; +} + +static void tracing_disarm_snapshot_locked(struct trace_array *tr) +{ + lockdep_assert_held(&trace_types_lock); + + if (WARN_ON(!tr->snapshot)) + return; + + tr->snapshot--; +} + +int tracing_arm_snapshot(struct trace_array *tr) +{ + int ret; + + mutex_lock(&trace_types_lock); + ret = tracing_arm_snapshot_locked(tr); + mutex_unlock(&trace_types_lock); + + return ret; +} + +void tracing_disarm_snapshot(struct trace_array *tr) +{ + mutex_lock(&trace_types_lock); + tracing_disarm_snapshot_locked(tr); + mutex_unlock(&trace_types_lock); +} + /** * tracing_alloc_snapshot - allocate snapshot buffer. * @@ -1373,10 +1419,6 @@ int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, mutex_lock(&trace_types_lock); - ret = tracing_alloc_snapshot_instance(tr); - if (ret) - goto fail_unlock; - if (tr->current_trace->use_max_tr) { ret = -EBUSY; goto fail_unlock; @@ -1395,6 +1437,10 @@ int tracing_snapshot_cond_enable(struct trace_array *tr, void *cond_data, goto fail_unlock; } + ret = tracing_arm_snapshot_locked(tr); + if (ret) + goto fail_unlock; + local_irq_disable(); arch_spin_lock(&tr->max_lock); tr->cond_snapshot = cond_snapshot; @@ -1439,6 +1485,8 @@ int tracing_snapshot_cond_disable(struct trace_array *tr) arch_spin_unlock(&tr->max_lock); local_irq_enable(); + tracing_disarm_snapshot(tr); + return ret; } EXPORT_SYMBOL_GPL(tracing_snapshot_cond_disable); @@ -6579,11 +6627,12 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) */ synchronize_rcu(); free_snapshot(tr); + tracing_disarm_snapshot_locked(tr); } - if (t->use_max_tr && !tr->allocated_snapshot) { - ret = tracing_alloc_snapshot_instance(tr); - if (ret < 0) + if (t->use_max_tr) { + ret = tracing_arm_snapshot_locked(tr); + if (ret) goto out; } #else @@ -6592,8 +6641,11 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) if (t->init) { ret = tracer_init(t, tr); - if (ret) + if (ret) { + if (t->use_max_tr) + tracing_disarm_snapshot_locked(tr); goto out; + } } tr->current_trace = t; @@ -7695,10 +7747,11 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt, if (tr->allocated_snapshot) ret = resize_buffer_duplicate_size(&tr->max_buffer, &tr->array_buffer, iter->cpu_file); - else - ret = tracing_alloc_snapshot_instance(tr); - if (ret < 0) + + ret = tracing_arm_snapshot_locked(tr); + if (ret) break; + /* Now, we're going to swap */ if (iter->cpu_file == RING_BUFFER_ALL_CPUS) { local_irq_disable(); @@ -7708,6 +7761,7 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt, smp_call_function_single(iter->cpu_file, tracing_swap_cpu_buffer, (void *)tr, 1); } + tracing_disarm_snapshot_locked(tr); break; default: if (tr->allocated_snapshot) { @@ -8832,8 +8886,13 @@ ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash, ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops; - if (glob[0] == '!') - return unregister_ftrace_function_probe_func(glob+1, tr, ops); + if (glob[0] == '!') { + ret = unregister_ftrace_function_probe_func(glob+1, tr, ops); + if (!ret) + tracing_disarm_snapshot(tr); + + return ret; + } if (!param) goto out_reg; @@ -8852,12 +8911,13 @@ ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash, return ret; out_reg: - ret = tracing_alloc_snapshot_instance(tr); + ret = tracing_arm_snapshot(tr); if (ret < 0) goto out; ret = register_ftrace_function_probe(glob, tr, ops, count); - + if (ret < 0) + tracing_disarm_snapshot(tr); out: return ret < 0 ? ret : 0; } diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 00f873910c5d..3aa06bd5e48d 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -334,6 +334,7 @@ struct trace_array { */ struct array_buffer max_buffer; bool allocated_snapshot; + unsigned int snapshot; #endif #ifdef CONFIG_TRACER_MAX_TRACE unsigned long max_latency; @@ -1973,12 +1974,16 @@ static inline void trace_event_eval_update(struct trace_eval_map **map, int len) #ifdef CONFIG_TRACER_SNAPSHOT void tracing_snapshot_instance(struct trace_array *tr); int tracing_alloc_snapshot_instance(struct trace_array *tr); +int tracing_arm_snapshot(struct trace_array *tr); +void tracing_disarm_snapshot(struct trace_array *tr); #else static inline void tracing_snapshot_instance(struct trace_array *tr) { } static inline int tracing_alloc_snapshot_instance(struct trace_array *tr) { return 0; } +static inline int tracing_arm_snapshot(struct trace_array *tr) { return 0; } +static inline void tracing_disarm_snapshot(struct trace_array *tr) { } #endif #ifdef CONFIG_PREEMPT_TRACER diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c index 46439e3bcec4..d41bf64741e2 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -597,20 +597,9 @@ static int register_trigger(char *glob, return ret; } -/** - * unregister_trigger - Generic event_command @unreg implementation - * @glob: The raw string used to register the trigger - * @test: Trigger-specific data used to find the trigger to remove - * @file: The trace_event_file associated with the event - * - * Common implementation for event trigger unregistration. - * - * Usually used directly as the @unreg method in event command - * implementations. - */ -static void unregister_trigger(char *glob, - struct event_trigger_data *test, - struct trace_event_file *file) +static bool __unregister_trigger(char *glob, + struct event_trigger_data *test, + struct trace_event_file *file) { struct event_trigger_data *data = NULL, *iter; @@ -626,8 +615,32 @@ static void unregister_trigger(char *glob, } } - if (data && data->ops->free) - data->ops->free(data); + if (data) { + if (data->ops->free) + data->ops->free(data); + + return true; + } + + return false; +} + +/** + * unregister_trigger - Generic event_command @unreg implementation + * @glob: The raw string used to register the trigger + * @test: Trigger-specific data used to find the trigger to remove + * @file: The trace_event_file associated with the event + * + * Common implementation for event trigger unregistration. + * + * Usually used directly as the @unreg method in event command + * implementations. + */ +static void unregister_trigger(char *glob, + struct event_trigger_data *test, + struct trace_event_file *file) +{ + __unregister_trigger(glob, test, file); } /* @@ -1470,12 +1483,20 @@ register_snapshot_trigger(char *glob, struct event_trigger_data *data, struct trace_event_file *file) { - if (tracing_alloc_snapshot_instance(file->tr) != 0) + if (tracing_arm_snapshot(file->tr)) return 0; return register_trigger(glob, data, file); } +static void unregister_snapshot_trigger(char *glob, + struct event_trigger_data *data, + struct trace_event_file *file) +{ + if (__unregister_trigger(glob, data, file)) + tracing_disarm_snapshot(file->tr); +} + static int snapshot_trigger_print(struct seq_file *m, struct event_trigger_data *data) { @@ -1508,7 +1529,7 @@ static struct event_command trigger_snapshot_cmd = { .trigger_type = ETT_SNAPSHOT, .parse = event_trigger_parse, .reg = register_snapshot_trigger, - .unreg = unregister_trigger, + .unreg = unregister_snapshot_trigger, .get_trigger_ops = snapshot_get_trigger_ops, .set_filter = set_trigger_filter, };
When a ring-buffer is memory mapped by user-space, no trace or ring-buffer swap is possible. This means the snapshot feature is mutually exclusive with the memory mapping. Having a refcount on snapshot users will help to know if a mapping is possible or not. Signed-off-by: Vincent Donnefort <vdonnefort@google.com>