From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/kernel/trace/trace.c | 125 ++++++++++++++++++++++++++++++++++++-----
1 files changed, 110 insertions(+), 15 deletions(-)
diff --git a/kernel/kernel/trace/trace.c b/kernel/kernel/trace/trace.c
index 8b1f74e..3992a50 100644
--- a/kernel/kernel/trace/trace.c
+++ b/kernel/kernel/trace/trace.c
@@ -1883,9 +1883,10 @@
* place on this CPU. We fail to record, but we reset
* the max trace buffer (no one writes directly to it)
* and flag that it failed.
+ * Another reason is resize is in progress.
*/
trace_array_printk_buf(tr->max_buffer.buffer, _THIS_IP_,
- "Failed to swap buffers due to commit in progress\n");
+ "Failed to swap buffers due to commit or resize in progress\n");
}
WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY);
@@ -2179,9 +2180,11 @@
}
/* Must have trace_types_lock held */
-void tracing_reset_all_online_cpus(void)
+void tracing_reset_all_online_cpus_unlocked(void)
{
struct trace_array *tr;
+
+ lockdep_assert_held(&trace_types_lock);
list_for_each_entry(tr, &ftrace_trace_arrays, list) {
if (!tr->clear_trace)
@@ -2192,6 +2195,13 @@
tracing_reset_online_cpus(&tr->max_buffer);
#endif
}
+}
+
+void tracing_reset_all_online_cpus(void)
+{
+ mutex_lock(&trace_types_lock);
+ tracing_reset_all_online_cpus_unlocked();
+ mutex_unlock(&trace_types_lock);
}
/*
@@ -3717,8 +3727,15 @@
* will point to the same string as current_trace->name.
*/
mutex_lock(&trace_types_lock);
- if (unlikely(tr->current_trace && iter->trace->name != tr->current_trace->name))
+ if (unlikely(tr->current_trace && iter->trace->name != tr->current_trace->name)) {
+ /* Close iter->trace before switching to the new current tracer */
+ if (iter->trace->close)
+ iter->trace->close(iter);
*iter->trace = *tr->current_trace;
+ /* Reopen the new current tracer */
+ if (iter->trace->open)
+ iter->trace->open(iter);
+ }
mutex_unlock(&trace_types_lock);
#ifdef CONFIG_TRACER_MAX_TRACE
@@ -4477,6 +4494,33 @@
return 0;
}
+/*
+ * The private pointer of the inode is the trace_event_file.
+ * Update the tr ref count associated to it.
+ */
+int tracing_open_file_tr(struct inode *inode, struct file *filp)
+{
+ struct trace_event_file *file = inode->i_private;
+ int ret;
+
+ ret = tracing_check_open_get_tr(file->tr);
+ if (ret)
+ return ret;
+
+ filp->private_data = inode->i_private;
+
+ return 0;
+}
+
+int tracing_release_file_tr(struct inode *inode, struct file *filp)
+{
+ struct trace_event_file *file = inode->i_private;
+
+ trace_array_put(file->tr);
+
+ return 0;
+}
+
static int tracing_release(struct inode *inode, struct file *file)
{
struct trace_array *tr = inode->i_private;
@@ -4706,6 +4750,8 @@
static const struct file_operations tracing_fops = {
.open = tracing_open,
.read = seq_read,
+ .read_iter = seq_read_iter,
+ .splice_read = generic_file_splice_read,
.write = tracing_write_stub,
.llseek = tracing_lseek,
.release = tracing_release,
@@ -4765,11 +4811,17 @@
!cpumask_test_cpu(cpu, tracing_cpumask_new)) {
atomic_inc(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
ring_buffer_record_disable_cpu(tr->array_buffer.buffer, cpu);
+#ifdef CONFIG_TRACER_MAX_TRACE
+ ring_buffer_record_disable_cpu(tr->max_buffer.buffer, cpu);
+#endif
}
if (!cpumask_test_cpu(cpu, tr->tracing_cpumask) &&
cpumask_test_cpu(cpu, tracing_cpumask_new)) {
atomic_dec(&per_cpu_ptr(tr->array_buffer.data, cpu)->disabled);
ring_buffer_record_enable_cpu(tr->array_buffer.buffer, cpu);
+#ifdef CONFIG_TRACER_MAX_TRACE
+ ring_buffer_record_enable_cpu(tr->max_buffer.buffer, cpu);
+#endif
}
}
arch_spin_unlock(&tr->max_lock);
@@ -6240,6 +6292,7 @@
mutex_unlock(&trace_types_lock);
free_cpumask_var(iter->started);
+ kfree(iter->temp);
mutex_destroy(&iter->mutex);
kfree(iter);
@@ -6372,7 +6425,20 @@
ret = print_trace_line(iter);
if (ret == TRACE_TYPE_PARTIAL_LINE) {
- /* don't print partial lines */
+ /*
+ * If one print_trace_line() fills entire trace_seq in one shot,
+ * trace_seq_to_user() will returns -EBUSY because save_len == 0,
+ * In this case, we need to consume it, otherwise, loop will peek
+ * this event next time, resulting in an infinite loop.
+ */
+ if (save_len == 0) {
+ iter->seq.full = 0;
+ trace_seq_puts(&iter->seq, "[LINE TOO BIG]\n");
+ trace_consume(iter);
+ break;
+ }
+
+ /* In other cases, don't print partial lines */
iter->seq.seq.len = save_len;
break;
}
@@ -7027,6 +7093,11 @@
return ret;
}
+static void tracing_swap_cpu_buffer(void *tr)
+{
+ update_max_tr_single((struct trace_array *)tr, current, smp_processor_id());
+}
+
static ssize_t
tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt,
loff_t *ppos)
@@ -7085,13 +7156,15 @@
ret = tracing_alloc_snapshot_instance(tr);
if (ret < 0)
break;
- local_irq_disable();
/* Now, we're going to swap */
- if (iter->cpu_file == RING_BUFFER_ALL_CPUS)
+ if (iter->cpu_file == RING_BUFFER_ALL_CPUS) {
+ local_irq_disable();
update_max_tr(tr, current, smp_processor_id(), NULL);
- else
- update_max_tr_single(tr, current, iter->cpu_file);
- local_irq_enable();
+ local_irq_enable();
+ } else {
+ smp_call_function_single(iter->cpu_file, tracing_swap_cpu_buffer,
+ (void *)tr, 1);
+ }
break;
default:
if (tr->allocated_snapshot) {
@@ -7180,10 +7253,11 @@
#endif
static const struct file_operations set_tracer_fops = {
- .open = tracing_open_generic,
+ .open = tracing_open_generic_tr,
.read = tracing_set_trace_read,
.write = tracing_set_trace_write,
.llseek = generic_file_llseek,
+ .release = tracing_release_generic_tr,
};
static const struct file_operations tracing_pipe_fops = {
@@ -7506,7 +7580,7 @@
.open = tracing_err_log_open,
.write = tracing_err_log_write,
.read = seq_read,
- .llseek = seq_lseek,
+ .llseek = tracing_lseek,
.release = tracing_err_log_release,
};
@@ -8222,12 +8296,33 @@
return cnt;
}
+static int tracing_open_options(struct inode *inode, struct file *filp)
+{
+ struct trace_option_dentry *topt = inode->i_private;
+ int ret;
+
+ ret = tracing_check_open_get_tr(topt->tr);
+ if (ret)
+ return ret;
+
+ filp->private_data = inode->i_private;
+ return 0;
+}
+
+static int tracing_release_options(struct inode *inode, struct file *file)
+{
+ struct trace_option_dentry *topt = file->private_data;
+
+ trace_array_put(topt->tr);
+ return 0;
+}
static const struct file_operations trace_options_fops = {
- .open = tracing_open_generic,
+ .open = tracing_open_options,
.read = trace_options_read,
.write = trace_options_write,
.llseek = generic_file_llseek,
+ .release = tracing_release_options,
};
/*
@@ -8557,9 +8652,6 @@
if (val > 100)
return -EINVAL;
- if (!val)
- val = 1;
-
tr->buffer_percent = val;
(*ppos)++;
@@ -8884,6 +8976,7 @@
ftrace_destroy_function_files(tr);
tracefs_remove(tr->dir);
free_trace_buffers(tr);
+ clear_tracing_err_log(tr);
for (i = 0; i < tr->nr_topts; i++) {
kfree(tr->topts[i].topts);
@@ -9706,6 +9799,8 @@
static_key_enable(&tracepoint_printk_key.key);
}
tracer_alloc_buffers();
+
+ init_events();
}
void __init trace_init(void)
--
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