* [PATCH v2 1/5] tracing: Remove unneeded goto out logic
2025-08-01 20:37 [PATCH v2 0/5] tracing: Cleanups with use of guard() and __free() Steven Rostedt
@ 2025-08-01 20:37 ` Steven Rostedt
2025-08-01 20:37 ` [PATCH v2 2/5] tracing: Add guard(ring_buffer_nest) Steven Rostedt
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Steven Rostedt @ 2025-08-01 20:37 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton
From: Steven Rostedt <rostedt@goodmis.org>
Several places in the trace.c file there's a goto out where the out is
simply a return. There's no reason to jump to the out label if it's not
doing any more logic but simply returning from the function.
Replace the goto outs with a return and remove the out labels.
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
kernel/trace/trace.c | 38 +++++++++++++++-----------------------
1 file changed, 15 insertions(+), 23 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 945a8ecf2c62..0ec9cab9a812 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1841,7 +1841,7 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
ret = get_user(ch, ubuf++);
if (ret)
- goto out;
+ return ret;
read++;
cnt--;
@@ -1855,7 +1855,7 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
while (cnt && isspace(ch)) {
ret = get_user(ch, ubuf++);
if (ret)
- goto out;
+ return ret;
read++;
cnt--;
}
@@ -1865,8 +1865,7 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
/* only spaces were written */
if (isspace(ch) || !ch) {
*ppos += read;
- ret = read;
- goto out;
+ return read;
}
}
@@ -1874,13 +1873,12 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
while (cnt && !isspace(ch) && ch) {
if (parser->idx < parser->size - 1)
parser->buffer[parser->idx++] = ch;
- else {
- ret = -EINVAL;
- goto out;
- }
+ else
+ return -EINVAL;
+
ret = get_user(ch, ubuf++);
if (ret)
- goto out;
+ return ret;
read++;
cnt--;
}
@@ -1895,15 +1893,11 @@ int trace_get_user(struct trace_parser *parser, const char __user *ubuf,
/* Make sure the parsed string always terminates with '\0'. */
parser->buffer[parser->idx] = 0;
} else {
- ret = -EINVAL;
- goto out;
+ return -EINVAL;
}
*ppos += read;
- ret = read;
-
-out:
- return ret;
+ return read;
}
/* TODO add a seq_buf_to_buffer() */
@@ -2405,10 +2399,10 @@ int __init register_tracer(struct tracer *type)
mutex_unlock(&trace_types_lock);
if (ret || !default_bootup_tracer)
- goto out_unlock;
+ return ret;
if (strncmp(default_bootup_tracer, type->name, MAX_TRACER_SIZE))
- goto out_unlock;
+ return 0;
printk(KERN_INFO "Starting tracer '%s'\n", type->name);
/* Do we want this tracer to start on bootup? */
@@ -2420,8 +2414,7 @@ int __init register_tracer(struct tracer *type)
/* disable other selftests, since this will break it. */
disable_tracing_selftest("running a tracer");
- out_unlock:
- return ret;
+ return 0;
}
static void tracing_reset_cpu(struct array_buffer *buf, int cpu)
@@ -8963,12 +8956,12 @@ ftrace_trace_snapshot_callback(struct trace_array *tr, struct ftrace_hash *hash,
out_reg:
ret = tracing_arm_snapshot(tr);
if (ret < 0)
- goto out;
+ return ret;
ret = register_ftrace_function_probe(glob, tr, ops, count);
if (ret < 0)
tracing_disarm_snapshot(tr);
- out:
+
return ret < 0 ? ret : 0;
}
@@ -11070,7 +11063,7 @@ __init static int tracer_alloc_buffers(void)
BUILD_BUG_ON(TRACE_ITER_LAST_BIT > TRACE_FLAGS_MAX_SIZE);
if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
- goto out;
+ return -ENOMEM;
if (!alloc_cpumask_var(&global_trace.tracing_cpumask, GFP_KERNEL))
goto out_free_buffer_mask;
@@ -11188,7 +11181,6 @@ __init static int tracer_alloc_buffers(void)
free_cpumask_var(global_trace.tracing_cpumask);
out_free_buffer_mask:
free_cpumask_var(tracing_buffer_mask);
-out:
return ret;
}
--
2.47.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v2 2/5] tracing: Add guard(ring_buffer_nest)
2025-08-01 20:37 [PATCH v2 0/5] tracing: Cleanups with use of guard() and __free() Steven Rostedt
2025-08-01 20:37 ` [PATCH v2 1/5] tracing: Remove unneeded goto out logic Steven Rostedt
@ 2025-08-01 20:37 ` Steven Rostedt
2025-08-01 20:37 ` [PATCH v2 3/5] tracing: Add guard() around locks and mutexes in trace.c Steven Rostedt
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: Steven Rostedt @ 2025-08-01 20:37 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton
From: Steven Rostedt <rostedt@goodmis.org>
Some calls to the tracing ring buffer can happen when the ring buffer is
already being written to by the same context (for example, a
trace_printk() in between a ring_buffer_lock_reserve() and a
ring_buffer_unlock_commit()).
In order to not trigger the recursion detection, these functions use
ring_buffer_nest_start() and ring_buffer_nest_end(). Create a guard() for
these functions so that their use cases can be simplified and not need to
use goto for the release.
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
include/linux/ring_buffer.h | 3 ++
kernel/trace/trace.c | 69 +++++++++++++------------------
kernel/trace/trace_events_synth.c | 6 +--
3 files changed, 34 insertions(+), 44 deletions(-)
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index cd7f0ae26615..8253cb69540c 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -144,6 +144,9 @@ int ring_buffer_write(struct trace_buffer *buffer,
void ring_buffer_nest_start(struct trace_buffer *buffer);
void ring_buffer_nest_end(struct trace_buffer *buffer);
+DEFINE_GUARD(ring_buffer_nest, struct trace_buffer *,
+ ring_buffer_nest_start(_T), ring_buffer_nest_end(_T))
+
struct ring_buffer_event *
ring_buffer_peek(struct trace_buffer *buffer, int cpu, u64 *ts,
unsigned long *lost_events);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 0ec9cab9a812..332487179e1d 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1160,13 +1160,11 @@ int __trace_array_puts(struct trace_array *tr, unsigned long ip,
trace_ctx = tracing_gen_ctx();
buffer = tr->array_buffer.buffer;
- ring_buffer_nest_start(buffer);
+ guard(ring_buffer_nest)(buffer);
event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, alloc,
trace_ctx);
- if (!event) {
- size = 0;
- goto out;
- }
+ if (!event)
+ return 0;
entry = ring_buffer_event_data(event);
entry->ip = ip;
@@ -1182,8 +1180,6 @@ int __trace_array_puts(struct trace_array *tr, unsigned long ip,
__buffer_unlock_commit(buffer, event);
ftrace_trace_stack(tr, buffer, trace_ctx, 4, NULL);
- out:
- ring_buffer_nest_end(buffer);
return size;
}
EXPORT_SYMBOL_GPL(__trace_array_puts);
@@ -1213,7 +1209,6 @@ int __trace_bputs(unsigned long ip, const char *str)
struct bputs_entry *entry;
unsigned int trace_ctx;
int size = sizeof(struct bputs_entry);
- int ret = 0;
if (!printk_binsafe(tr))
return __trace_puts(ip, str, strlen(str));
@@ -1227,11 +1222,11 @@ int __trace_bputs(unsigned long ip, const char *str)
trace_ctx = tracing_gen_ctx();
buffer = tr->array_buffer.buffer;
- ring_buffer_nest_start(buffer);
+ guard(ring_buffer_nest)(buffer);
event = __trace_buffer_lock_reserve(buffer, TRACE_BPUTS, size,
trace_ctx);
if (!event)
- goto out;
+ return 0;
entry = ring_buffer_event_data(event);
entry->ip = ip;
@@ -1240,10 +1235,7 @@ int __trace_bputs(unsigned long ip, const char *str)
__buffer_unlock_commit(buffer, event);
ftrace_trace_stack(tr, buffer, trace_ctx, 4, NULL);
- ret = 1;
- out:
- ring_buffer_nest_end(buffer);
- return ret;
+ return 1;
}
EXPORT_SYMBOL_GPL(__trace_bputs);
@@ -3397,21 +3389,19 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
size = sizeof(*entry) + sizeof(u32) * len;
buffer = tr->array_buffer.buffer;
- ring_buffer_nest_start(buffer);
- event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
- trace_ctx);
- if (!event)
- goto out;
- entry = ring_buffer_event_data(event);
- entry->ip = ip;
- entry->fmt = fmt;
-
- memcpy(entry->buf, tbuffer, sizeof(u32) * len);
- __buffer_unlock_commit(buffer, event);
- ftrace_trace_stack(tr, buffer, trace_ctx, 6, NULL);
+ scoped_guard(ring_buffer_nest, buffer) {
+ event = __trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
+ trace_ctx);
+ if (!event)
+ goto out_put;
+ entry = ring_buffer_event_data(event);
+ entry->ip = ip;
+ entry->fmt = fmt;
-out:
- ring_buffer_nest_end(buffer);
+ memcpy(entry->buf, tbuffer, sizeof(u32) * len);
+ __buffer_unlock_commit(buffer, event);
+ ftrace_trace_stack(tr, buffer, trace_ctx, 6, NULL);
+ }
out_put:
put_trace_buf();
@@ -3452,20 +3442,19 @@ int __trace_array_vprintk(struct trace_buffer *buffer,
len = vscnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
size = sizeof(*entry) + len + 1;
- ring_buffer_nest_start(buffer);
- event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
- trace_ctx);
- if (!event)
- goto out;
- entry = ring_buffer_event_data(event);
- entry->ip = ip;
-
- memcpy(&entry->buf, tbuffer, len + 1);
- __buffer_unlock_commit(buffer, event);
- ftrace_trace_stack(printk_trace, buffer, trace_ctx, 6, NULL);
+ scoped_guard(ring_buffer_nest, buffer) {
+ event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
+ trace_ctx);
+ if (!event)
+ goto out;
+ entry = ring_buffer_event_data(event);
+ entry->ip = ip;
+ memcpy(&entry->buf, tbuffer, len + 1);
+ __buffer_unlock_commit(buffer, event);
+ ftrace_trace_stack(printk_trace, buffer, trace_ctx, 6, NULL);
+ }
out:
- ring_buffer_nest_end(buffer);
put_trace_buf();
out_nobuffer:
diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c
index 33cfbd4ed76d..f24ee61f8884 100644
--- a/kernel/trace/trace_events_synth.c
+++ b/kernel/trace/trace_events_synth.c
@@ -536,12 +536,12 @@ static notrace void trace_event_raw_event_synth(void *__data,
* is being performed within another event.
*/
buffer = trace_file->tr->array_buffer.buffer;
- ring_buffer_nest_start(buffer);
+ guard(ring_buffer_nest)(buffer);
entry = trace_event_buffer_reserve(&fbuffer, trace_file,
sizeof(*entry) + fields_size);
if (!entry)
- goto out;
+ return;
for (i = 0, n_u64 = 0; i < event->n_fields; i++) {
val_idx = var_ref_idx[i];
@@ -584,8 +584,6 @@ static notrace void trace_event_raw_event_synth(void *__data,
}
trace_event_buffer_commit(&fbuffer);
-out:
- ring_buffer_nest_end(buffer);
}
static void free_synth_event_print_fmt(struct trace_event_call *call)
--
2.47.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v2 3/5] tracing: Add guard() around locks and mutexes in trace.c
2025-08-01 20:37 [PATCH v2 0/5] tracing: Cleanups with use of guard() and __free() Steven Rostedt
2025-08-01 20:37 ` [PATCH v2 1/5] tracing: Remove unneeded goto out logic Steven Rostedt
2025-08-01 20:37 ` [PATCH v2 2/5] tracing: Add guard(ring_buffer_nest) Steven Rostedt
@ 2025-08-01 20:37 ` Steven Rostedt
2025-08-01 20:37 ` [PATCH v2 4/5] tracing: Use __free(kfree) in trace.c to remove gotos Steven Rostedt
2025-08-01 20:37 ` [PATCH v2 5/5] ring-buffer: Convert ring_buffer_write() to use guard(preempt_notrace) Steven Rostedt
4 siblings, 0 replies; 6+ messages in thread
From: Steven Rostedt @ 2025-08-01 20:37 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton
From: Steven Rostedt <rostedt@goodmis.org>
There's several locations in trace.c that can be simplified by using
guards around raw_spin_lock_irqsave, mutexes and preempt disabling.
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
Changes since v1: https://lore.kernel.org/20250801142526.649674199@kernel.org
- Do not use guard(preempt) for trace_event_buffer_lock_reserve() as that
returns with preemption enabled between the disable and enable preempt.
kernel/trace/trace.c | 144 ++++++++++++++-----------------------------
1 file changed, 46 insertions(+), 98 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 332487179e1d..4299e89ed04e 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -432,15 +432,13 @@ static void ftrace_exports(struct ring_buffer_event *event, int flag)
{
struct trace_export *export;
- preempt_disable_notrace();
+ guard(preempt_notrace)();
export = rcu_dereference_raw_check(ftrace_exports_list);
while (export) {
trace_process_export(export, event, flag);
export = rcu_dereference_raw_check(export->next);
}
-
- preempt_enable_notrace();
}
static inline void
@@ -497,27 +495,18 @@ int register_ftrace_export(struct trace_export *export)
if (WARN_ON_ONCE(!export->write))
return -1;
- mutex_lock(&ftrace_export_lock);
+ guard(mutex)(&ftrace_export_lock);
add_ftrace_export(&ftrace_exports_list, export);
- mutex_unlock(&ftrace_export_lock);
-
return 0;
}
EXPORT_SYMBOL_GPL(register_ftrace_export);
int unregister_ftrace_export(struct trace_export *export)
{
- int ret;
-
- mutex_lock(&ftrace_export_lock);
-
- ret = rm_ftrace_export(&ftrace_exports_list, export);
-
- mutex_unlock(&ftrace_export_lock);
-
- return ret;
+ guard(mutex)(&ftrace_export_lock);
+ return rm_ftrace_export(&ftrace_exports_list, export);
}
EXPORT_SYMBOL_GPL(unregister_ftrace_export);
@@ -640,9 +629,8 @@ void trace_array_put(struct trace_array *this_tr)
if (!this_tr)
return;
- mutex_lock(&trace_types_lock);
+ guard(mutex)(&trace_types_lock);
__trace_array_put(this_tr);
- mutex_unlock(&trace_types_lock);
}
EXPORT_SYMBOL_GPL(trace_array_put);
@@ -1424,13 +1412,8 @@ static int tracing_arm_snapshot_locked(struct trace_array *tr)
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;
+ guard(mutex)(&trace_types_lock);
+ return tracing_arm_snapshot_locked(tr);
}
void tracing_disarm_snapshot(struct trace_array *tr)
@@ -2483,9 +2466,8 @@ void tracing_reset_all_online_cpus_unlocked(void)
void tracing_reset_all_online_cpus(void)
{
- mutex_lock(&trace_types_lock);
+ guard(mutex)(&trace_types_lock);
tracing_reset_all_online_cpus_unlocked();
- mutex_unlock(&trace_types_lock);
}
int is_tracing_stopped(void)
@@ -2496,18 +2478,17 @@ int is_tracing_stopped(void)
static void tracing_start_tr(struct trace_array *tr)
{
struct trace_buffer *buffer;
- unsigned long flags;
if (tracing_disabled)
return;
- raw_spin_lock_irqsave(&tr->start_lock, flags);
+ guard(raw_spinlock_irqsave)(&tr->start_lock);
if (--tr->stop_count) {
if (WARN_ON_ONCE(tr->stop_count < 0)) {
/* Someone screwed up their debugging */
tr->stop_count = 0;
}
- goto out;
+ return;
}
/* Prevent the buffers from switching */
@@ -2524,9 +2505,6 @@ static void tracing_start_tr(struct trace_array *tr)
#endif
arch_spin_unlock(&tr->max_lock);
-
- out:
- raw_spin_unlock_irqrestore(&tr->start_lock, flags);
}
/**
@@ -2544,11 +2522,10 @@ void tracing_start(void)
static void tracing_stop_tr(struct trace_array *tr)
{
struct trace_buffer *buffer;
- unsigned long flags;
- raw_spin_lock_irqsave(&tr->start_lock, flags);
+ guard(raw_spinlock_irqsave)(&tr->start_lock);
if (tr->stop_count++)
- goto out;
+ return;
/* Prevent the buffers from switching */
arch_spin_lock(&tr->max_lock);
@@ -2564,9 +2541,6 @@ static void tracing_stop_tr(struct trace_array *tr)
#endif
arch_spin_unlock(&tr->max_lock);
-
- out:
- raw_spin_unlock_irqrestore(&tr->start_lock, flags);
}
/**
@@ -2679,12 +2653,12 @@ void trace_buffered_event_enable(void)
per_cpu(trace_buffered_event, cpu) = event;
- preempt_disable();
- if (cpu == smp_processor_id() &&
- __this_cpu_read(trace_buffered_event) !=
- per_cpu(trace_buffered_event, cpu))
- WARN_ON_ONCE(1);
- preempt_enable();
+ scoped_guard(preempt,) {
+ if (cpu == smp_processor_id() &&
+ __this_cpu_read(trace_buffered_event) !=
+ per_cpu(trace_buffered_event, cpu))
+ WARN_ON_ONCE(1);
+ }
}
}
@@ -3029,7 +3003,7 @@ static void __ftrace_trace_stack(struct trace_array *tr,
skip++;
#endif
- preempt_disable_notrace();
+ guard(preempt_notrace)();
stackidx = __this_cpu_inc_return(ftrace_stack_reserve) - 1;
@@ -3087,8 +3061,6 @@ static void __ftrace_trace_stack(struct trace_array *tr,
/* Again, don't let gcc optimize things here */
barrier();
__this_cpu_dec(ftrace_stack_reserve);
- preempt_enable_notrace();
-
}
static inline void ftrace_trace_stack(struct trace_array *tr,
@@ -3171,9 +3143,9 @@ ftrace_trace_userstack(struct trace_array *tr,
* prevent recursion, since the user stack tracing may
* trigger other kernel events.
*/
- preempt_disable();
+ guard(preempt)();
if (__this_cpu_read(user_stack_count))
- goto out;
+ return;
__this_cpu_inc(user_stack_count);
@@ -3191,8 +3163,6 @@ ftrace_trace_userstack(struct trace_array *tr,
out_drop_count:
__this_cpu_dec(user_stack_count);
- out:
- preempt_enable();
}
#else /* CONFIG_USER_STACKTRACE_SUPPORT */
static void ftrace_trace_userstack(struct trace_array *tr,
@@ -3374,7 +3344,7 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
pause_graph_tracing();
trace_ctx = tracing_gen_ctx();
- preempt_disable_notrace();
+ guard(preempt_notrace)();
tbuffer = get_trace_buf();
if (!tbuffer) {
@@ -3406,7 +3376,6 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
put_trace_buf();
out_nobuffer:
- preempt_enable_notrace();
unpause_graph_tracing();
return len;
@@ -3430,7 +3399,7 @@ int __trace_array_vprintk(struct trace_buffer *buffer,
pause_graph_tracing();
trace_ctx = tracing_gen_ctx();
- preempt_disable_notrace();
+ guard(preempt_notrace)();
tbuffer = get_trace_buf();
@@ -3458,7 +3427,6 @@ int __trace_array_vprintk(struct trace_buffer *buffer,
put_trace_buf();
out_nobuffer:
- preempt_enable_notrace();
unpause_graph_tracing();
return len;
@@ -4788,20 +4756,16 @@ int tracing_open_file_tr(struct inode *inode, struct file *filp)
if (ret)
return ret;
- mutex_lock(&event_mutex);
+ guard(mutex)(&event_mutex);
/* Fail if the file is marked for removal */
if (file->flags & EVENT_FILE_FL_FREED) {
trace_array_put(file->tr);
- ret = -ENODEV;
+ return -ENODEV;
} else {
event_file_get(file);
}
- mutex_unlock(&event_mutex);
- if (ret)
- return ret;
-
filp->private_data = inode->i_private;
return 0;
@@ -5945,9 +5909,9 @@ tracing_set_trace_read(struct file *filp, char __user *ubuf,
char buf[MAX_TRACER_SIZE+2];
int r;
- mutex_lock(&trace_types_lock);
- r = sprintf(buf, "%s\n", tr->current_trace->name);
- mutex_unlock(&trace_types_lock);
+ scoped_guard(mutex, &trace_types_lock) {
+ r = sprintf(buf, "%s\n", tr->current_trace->name);
+ }
return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
}
@@ -6249,15 +6213,13 @@ int tracing_update_buffers(struct trace_array *tr)
{
int ret = 0;
- mutex_lock(&trace_types_lock);
+ guard(mutex)(&trace_types_lock);
update_last_data(tr);
if (!tr->ring_buffer_expanded)
ret = __tracing_resize_ring_buffer(tr, trace_buf_size,
RING_BUFFER_ALL_CPUS);
- mutex_unlock(&trace_types_lock);
-
return ret;
}
@@ -6554,7 +6516,7 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
if (ret)
return ret;
- mutex_lock(&trace_types_lock);
+ guard(mutex)(&trace_types_lock);
cpu = tracing_get_cpu(inode);
ret = open_pipe_on_cpu(tr, cpu);
if (ret)
@@ -6598,7 +6560,6 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
tr->trace_ref++;
- mutex_unlock(&trace_types_lock);
return ret;
fail:
@@ -6607,7 +6568,6 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp)
close_pipe_on_cpu(tr, cpu);
fail_pipe_on_cpu:
__trace_array_put(tr);
- mutex_unlock(&trace_types_lock);
return ret;
}
@@ -6616,14 +6576,13 @@ static int tracing_release_pipe(struct inode *inode, struct file *file)
struct trace_iterator *iter = file->private_data;
struct trace_array *tr = inode->i_private;
- mutex_lock(&trace_types_lock);
+ scoped_guard(mutex, &trace_types_lock) {
+ tr->trace_ref--;
- tr->trace_ref--;
-
- if (iter->trace->pipe_close)
- iter->trace->pipe_close(iter);
- close_pipe_on_cpu(tr, iter->cpu_file);
- mutex_unlock(&trace_types_lock);
+ if (iter->trace->pipe_close)
+ iter->trace->pipe_close(iter);
+ close_pipe_on_cpu(tr, iter->cpu_file);
+ }
free_trace_iter_content(iter);
kfree(iter);
@@ -7426,7 +7385,7 @@ int tracing_set_clock(struct trace_array *tr, const char *clockstr)
if (i == ARRAY_SIZE(trace_clocks))
return -EINVAL;
- mutex_lock(&trace_types_lock);
+ guard(mutex)(&trace_types_lock);
tr->clock_id = i;
@@ -7450,8 +7409,6 @@ int tracing_set_clock(struct trace_array *tr, const char *clockstr)
tscratch->clock_id = i;
}
- mutex_unlock(&trace_types_lock);
-
return 0;
}
@@ -7503,15 +7460,13 @@ static int tracing_time_stamp_mode_show(struct seq_file *m, void *v)
{
struct trace_array *tr = m->private;
- mutex_lock(&trace_types_lock);
+ guard(mutex)(&trace_types_lock);
if (ring_buffer_time_stamp_abs(tr->array_buffer.buffer))
seq_puts(m, "delta [absolute]\n");
else
seq_puts(m, "[delta] absolute\n");
- mutex_unlock(&trace_types_lock);
-
return 0;
}
@@ -8099,14 +8054,14 @@ static void clear_tracing_err_log(struct trace_array *tr)
{
struct tracing_log_err *err, *next;
- mutex_lock(&tracing_err_log_lock);
+ guard(mutex)(&tracing_err_log_lock);
+
list_for_each_entry_safe(err, next, &tr->err_log, list) {
list_del(&err->list);
free_tracing_log_err(err);
}
tr->n_err_log_entries = 0;
- mutex_unlock(&tracing_err_log_lock);
}
static void *tracing_err_log_seq_start(struct seq_file *m, loff_t *pos)
@@ -8377,7 +8332,7 @@ static int tracing_buffers_release(struct inode *inode, struct file *file)
struct ftrace_buffer_info *info = file->private_data;
struct trace_iterator *iter = &info->iter;
- mutex_lock(&trace_types_lock);
+ guard(mutex)(&trace_types_lock);
iter->tr->trace_ref--;
@@ -8388,8 +8343,6 @@ static int tracing_buffers_release(struct inode *inode, struct file *file)
info->spare_cpu, info->spare);
kvfree(info);
- mutex_unlock(&trace_types_lock);
-
return 0;
}
@@ -8597,14 +8550,13 @@ static long tracing_buffers_ioctl(struct file *file, unsigned int cmd, unsigned
* An ioctl call with cmd 0 to the ring buffer file will wake up all
* waiters
*/
- mutex_lock(&trace_types_lock);
+ guard(mutex)(&trace_types_lock);
/* Make sure the waiters see the new wait_index */
(void)atomic_fetch_inc_release(&iter->wait_index);
ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
- mutex_unlock(&trace_types_lock);
return 0;
}
@@ -9094,10 +9046,9 @@ trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt,
return -EINVAL;
if (!!(topt->flags->val & topt->opt->bit) != val) {
- mutex_lock(&trace_types_lock);
+ guard(mutex)(&trace_types_lock);
ret = __set_tracer_option(topt->tr, topt->flags,
topt->opt, !val);
- mutex_unlock(&trace_types_lock);
if (ret)
return ret;
}
@@ -9406,7 +9357,7 @@ rb_simple_write(struct file *filp, const char __user *ubuf,
return ret;
if (buffer) {
- mutex_lock(&trace_types_lock);
+ guard(mutex)(&trace_types_lock);
if (!!val == tracer_tracing_is_on(tr)) {
val = 0; /* do nothing */
} else if (val) {
@@ -9420,7 +9371,6 @@ rb_simple_write(struct file *filp, const char __user *ubuf,
/* Wake up any waiters */
ring_buffer_wake_waiters(buffer, RING_BUFFER_ALL_CPUS);
}
- mutex_unlock(&trace_types_lock);
}
(*ppos)++;
@@ -9804,10 +9754,9 @@ static void __update_tracer_options(struct trace_array *tr)
static void update_tracer_options(struct trace_array *tr)
{
- mutex_lock(&trace_types_lock);
+ guard(mutex)(&trace_types_lock);
tracer_options_updated = true;
__update_tracer_options(tr);
- mutex_unlock(&trace_types_lock);
}
/* Must have trace_types_lock held */
@@ -9829,11 +9778,10 @@ struct trace_array *trace_array_find_get(const char *instance)
{
struct trace_array *tr;
- mutex_lock(&trace_types_lock);
+ guard(mutex)(&trace_types_lock);
tr = trace_array_find(instance);
if (tr)
tr->ref++;
- mutex_unlock(&trace_types_lock);
return tr;
}
--
2.47.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v2 4/5] tracing: Use __free(kfree) in trace.c to remove gotos
2025-08-01 20:37 [PATCH v2 0/5] tracing: Cleanups with use of guard() and __free() Steven Rostedt
` (2 preceding siblings ...)
2025-08-01 20:37 ` [PATCH v2 3/5] tracing: Add guard() around locks and mutexes in trace.c Steven Rostedt
@ 2025-08-01 20:37 ` Steven Rostedt
2025-08-01 20:37 ` [PATCH v2 5/5] ring-buffer: Convert ring_buffer_write() to use guard(preempt_notrace) Steven Rostedt
4 siblings, 0 replies; 6+ messages in thread
From: Steven Rostedt @ 2025-08-01 20:37 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton
From: Steven Rostedt <rostedt@goodmis.org>
There's a couple of locations that have goto out in trace.c for the only
purpose of freeing a variable that was allocated. These can be replaced
with __free(kfree).
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
kernel/trace/trace.c | 36 ++++++++++++------------------------
1 file changed, 12 insertions(+), 24 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 4299e89ed04e..d0b1964648c1 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5042,7 +5042,7 @@ tracing_cpumask_read(struct file *filp, char __user *ubuf,
size_t count, loff_t *ppos)
{
struct trace_array *tr = file_inode(filp)->i_private;
- char *mask_str;
+ char *mask_str __free(kfree) = NULL;
int len;
len = snprintf(NULL, 0, "%*pb\n",
@@ -5053,16 +5053,10 @@ tracing_cpumask_read(struct file *filp, char __user *ubuf,
len = snprintf(mask_str, len, "%*pb\n",
cpumask_pr_args(tr->tracing_cpumask));
- if (len >= count) {
- count = -EINVAL;
- goto out_err;
- }
- count = simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
-
-out_err:
- kfree(mask_str);
+ if (len >= count)
+ return -EINVAL;
- return count;
+ return simple_read_from_buffer(ubuf, count, ppos, mask_str, len);
}
int tracing_set_cpumask(struct trace_array *tr,
@@ -10739,7 +10733,8 @@ ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos,
int (*createfn)(const char *))
{
- char *kbuf, *buf, *tmp;
+ char *kbuf __free(kfree) = NULL;
+ char *buf, *tmp;
int ret = 0;
size_t done = 0;
size_t size;
@@ -10754,10 +10749,9 @@ ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
if (size >= WRITE_BUFSIZE)
size = WRITE_BUFSIZE - 1;
- if (copy_from_user(kbuf, buffer + done, size)) {
- ret = -EFAULT;
- goto out;
- }
+ if (copy_from_user(kbuf, buffer + done, size))
+ return -EFAULT;
+
kbuf[size] = '\0';
buf = kbuf;
do {
@@ -10773,8 +10767,7 @@ ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
/* This can accept WRITE_BUFSIZE - 2 ('\n' + '\0') */
pr_warn("Line length is too long: Should be less than %d\n",
WRITE_BUFSIZE - 2);
- ret = -EINVAL;
- goto out;
+ return -EINVAL;
}
}
done += size;
@@ -10787,17 +10780,12 @@ ssize_t trace_parse_run_command(struct file *file, const char __user *buffer,
ret = createfn(buf);
if (ret)
- goto out;
+ return ret;
buf += size;
} while (done < count);
}
- ret = done;
-
-out:
- kfree(kbuf);
-
- return ret;
+ return done;
}
#ifdef CONFIG_TRACER_MAX_TRACE
--
2.47.2
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v2 5/5] ring-buffer: Convert ring_buffer_write() to use guard(preempt_notrace)
2025-08-01 20:37 [PATCH v2 0/5] tracing: Cleanups with use of guard() and __free() Steven Rostedt
` (3 preceding siblings ...)
2025-08-01 20:37 ` [PATCH v2 4/5] tracing: Use __free(kfree) in trace.c to remove gotos Steven Rostedt
@ 2025-08-01 20:37 ` Steven Rostedt
4 siblings, 0 replies; 6+ messages in thread
From: Steven Rostedt @ 2025-08-01 20:37 UTC (permalink / raw)
To: linux-kernel, linux-trace-kernel
Cc: Masami Hiramatsu, Mark Rutland, Mathieu Desnoyers, Andrew Morton
From: Steven Rostedt <rostedt@goodmis.org>
The function ring_buffer_write() has a goto out to only do a
preempt_enable_notrace(). This can be replaced by a guard.
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
kernel/trace/ring_buffer.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 00fc38d70e86..9d7bf17fbfba 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -4714,26 +4714,26 @@ int ring_buffer_write(struct trace_buffer *buffer,
int ret = -EBUSY;
int cpu;
- preempt_disable_notrace();
+ guard(preempt_notrace)();
if (atomic_read(&buffer->record_disabled))
- goto out;
+ return -EBUSY;
cpu = raw_smp_processor_id();
if (!cpumask_test_cpu(cpu, buffer->cpumask))
- goto out;
+ return -EBUSY;
cpu_buffer = buffer->buffers[cpu];
if (atomic_read(&cpu_buffer->record_disabled))
- goto out;
+ return -EBUSY;
if (length > buffer->max_data_size)
- goto out;
+ return -EBUSY;
if (unlikely(trace_recursive_lock(cpu_buffer)))
- goto out;
+ return -EBUSY;
event = rb_reserve_next_event(buffer, cpu_buffer, length);
if (!event)
@@ -4751,10 +4751,6 @@ int ring_buffer_write(struct trace_buffer *buffer,
out_unlock:
trace_recursive_unlock(cpu_buffer);
-
- out:
- preempt_enable_notrace();
-
return ret;
}
EXPORT_SYMBOL_GPL(ring_buffer_write);
--
2.47.2
^ permalink raw reply related [flat|nested] 6+ messages in thread