diff --git a/include/linux/trace_seq.h b/include/linux/trace_seq.h
index 9ec229dfddaa774b9c0a4f2ae410eb273061c330..1ef95c0287f05daed3a1096ad9d5a4cf66dd0f3e 100644
--- a/include/linux/trace_seq.h
+++ b/include/linux/trace_seq.h
@@ -9,9 +9,15 @@
/*
* Trace sequences are used to allow a function to call several other functions
* to create a string of data to use.
+ *
+ * Have the trace seq to be 8K which is typically PAGE_SIZE * 2 on
+ * most architectures. The TRACE_SEQ_BUFFER_SIZE (which is
+ * TRACE_SEQ_SIZE minus the other fields of trace_seq), is the
+ * max size the output of a trace event may be.
*/
-#define TRACE_SEQ_BUFFER_SIZE (PAGE_SIZE * 2 - \
+#define TRACE_SEQ_SIZE 8192
+#define TRACE_SEQ_BUFFER_SIZE (TRACE_SEQ_SIZE - \
(sizeof(struct seq_buf) + sizeof(size_t) + sizeof(int)))
struct trace_seq {
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 0699027b4f4c92d3a6ed7c62ee64491d7cd89046..aa332ace108b18169b3c67198a4fc0b621670b00 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -384,7 +384,6 @@ struct rb_irq_work {
struct irq_work work;
wait_queue_head_t waiters;
wait_queue_head_t full_waiters;
- long wait_index;
bool waiters_pending;
bool full_waiters_pending;
bool wakeup_full;
@@ -756,8 +755,19 @@ static void rb_wake_up_waiters(struct irq_work *work)
wake_up_all(&rbwork->waiters);
if (rbwork->full_waiters_pending || rbwork->wakeup_full) {
+ /* Only cpu_buffer sets the above flags */
+ struct ring_buffer_per_cpu *cpu_buffer =
+ container_of(rbwork, struct ring_buffer_per_cpu, irq_work);
+
+ /* Called from interrupt context */
+ raw_spin_lock(&cpu_buffer->reader_lock);
rbwork->wakeup_full = false;
rbwork->full_waiters_pending = false;
+
+ /* Waking up all waiters, they will reset the shortest full */
+ cpu_buffer->shortest_full = 0;
+ raw_spin_unlock(&cpu_buffer->reader_lock);
+
wake_up_all(&rbwork->full_waiters);
}
}
@@ -798,14 +808,40 @@ void ring_buffer_wake_waiters(struct trace_buffer *buffer, int cpu)
rbwork = &cpu_buffer->irq_work;
}
- rbwork->wait_index++;
- /* make sure the waiters see the new index */
- smp_wmb();
-
/* This can be called in any context */
irq_work_queue(&rbwork->work);
}
+static bool rb_watermark_hit(struct trace_buffer *buffer, int cpu, int full)
+{
+ struct ring_buffer_per_cpu *cpu_buffer;
+ bool ret = false;
+
+ /* Reads of all CPUs always waits for any data */
+ if (cpu == RING_BUFFER_ALL_CPUS)
+ return !ring_buffer_empty(buffer);
+
+ cpu_buffer = buffer->buffers[cpu];
+
+ if (!ring_buffer_empty_cpu(buffer, cpu)) {
+ unsigned long flags;
+ bool pagebusy;
+
+ if (!full)
+ return true;
+
+ raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+ pagebusy = cpu_buffer->reader_page == cpu_buffer->commit_page;
+ ret = !pagebusy && full_hit(buffer, cpu, full);
+
+ if (!cpu_buffer->shortest_full ||
+ cpu_buffer->shortest_full > full)
+ cpu_buffer->shortest_full = full;
+ raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
+ }
+ return ret;
+}
+
/**
* ring_buffer_wait - wait for input to the ring buffer
* @buffer: buffer to wait on
@@ -821,7 +857,6 @@ int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full)
struct ring_buffer_per_cpu *cpu_buffer;
DEFINE_WAIT(wait);
struct rb_irq_work *work;
- long wait_index;
int ret = 0;
/*
@@ -840,81 +875,54 @@ int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full)
work = &cpu_buffer->irq_work;
}
- wait_index = READ_ONCE(work->wait_index);
-
- while (true) {
- if (full)
- prepare_to_wait(&work->full_waiters, &wait, TASK_INTERRUPTIBLE);
- else
- prepare_to_wait(&work->waiters, &wait, TASK_INTERRUPTIBLE);
-
- /*
- * The events can happen in critical sections where
- * checking a work queue can cause deadlocks.
- * After adding a task to the queue, this flag is set
- * only to notify events to try to wake up the queue
- * using irq_work.
- *
- * We don't clear it even if the buffer is no longer
- * empty. The flag only causes the next event to run
- * irq_work to do the work queue wake up. The worse
- * that can happen if we race with !trace_empty() is that
- * an event will cause an irq_work to try to wake up
- * an empty queue.
- *
- * There's no reason to protect this flag either, as
- * the work queue and irq_work logic will do the necessary
- * synchronization for the wake ups. The only thing
- * that is necessary is that the wake up happens after
- * a task has been queued. It's OK for spurious wake ups.
- */
- if (full)
- work->full_waiters_pending = true;
- else
- work->waiters_pending = true;
-
- if (signal_pending(current)) {
- ret = -EINTR;
- break;
- }
-
- if (cpu == RING_BUFFER_ALL_CPUS && !ring_buffer_empty(buffer))
- break;
-
- if (cpu != RING_BUFFER_ALL_CPUS &&
- !ring_buffer_empty_cpu(buffer, cpu)) {
- unsigned long flags;
- bool pagebusy;
- bool done;
-
- if (!full)
- break;
-
- raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
- pagebusy = cpu_buffer->reader_page == cpu_buffer->commit_page;
- done = !pagebusy && full_hit(buffer, cpu, full);
+ if (full)
+ prepare_to_wait(&work->full_waiters, &wait, TASK_INTERRUPTIBLE);
+ else
+ prepare_to_wait(&work->waiters, &wait, TASK_INTERRUPTIBLE);
- if (!cpu_buffer->shortest_full ||
- cpu_buffer->shortest_full > full)
- cpu_buffer->shortest_full = full;
- raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
- if (done)
- break;
- }
+ /*
+ * The events can happen in critical sections where
+ * checking a work queue can cause deadlocks.
+ * After adding a task to the queue, this flag is set
+ * only to notify events to try to wake up the queue
+ * using irq_work.
+ *
+ * We don't clear it even if the buffer is no longer
+ * empty. The flag only causes the next event to run
+ * irq_work to do the work queue wake up. The worse
+ * that can happen if we race with !trace_empty() is that
+ * an event will cause an irq_work to try to wake up
+ * an empty queue.
+ *
+ * There's no reason to protect this flag either, as
+ * the work queue and irq_work logic will do the necessary
+ * synchronization for the wake ups. The only thing
+ * that is necessary is that the wake up happens after
+ * a task has been queued. It's OK for spurious wake ups.
+ */
+ if (full)
+ work->full_waiters_pending = true;
+ else
+ work->waiters_pending = true;
- schedule();
+ if (rb_watermark_hit(buffer, cpu, full))
+ goto out;
- /* Make sure to see the new wait index */
- smp_rmb();
- if (wait_index != work->wait_index)
- break;
+ if (signal_pending(current)) {
+ ret = -EINTR;
+ goto out;
}
+ schedule();
+ out:
if (full)
finish_wait(&work->full_waiters, &wait);
else
finish_wait(&work->waiters, &wait);
+ if (!ret && !rb_watermark_hit(buffer, cpu, full) && signal_pending(current))
+ ret = -EINTR;
+
return ret;
}
@@ -937,28 +945,33 @@ __poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu,
struct file *filp, poll_table *poll_table, int full)
{
struct ring_buffer_per_cpu *cpu_buffer;
- struct rb_irq_work *work;
+ struct rb_irq_work *rbwork;
if (cpu == RING_BUFFER_ALL_CPUS) {
- work = &buffer->irq_work;
+ rbwork = &buffer->irq_work;
full = 0;
} else {
if (!cpumask_test_cpu(cpu, buffer->cpumask))
return EPOLLERR;
cpu_buffer = buffer->buffers[cpu];
- work = &cpu_buffer->irq_work;
+ rbwork = &cpu_buffer->irq_work;
}
if (full) {
- poll_wait(filp, &work->full_waiters, poll_table);
- work->full_waiters_pending = true;
+ unsigned long flags;
+
+ poll_wait(filp, &rbwork->full_waiters, poll_table);
+
+ raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
+ rbwork->full_waiters_pending = true;
if (!cpu_buffer->shortest_full ||
cpu_buffer->shortest_full > full)
cpu_buffer->shortest_full = full;
+ raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
} else {
- poll_wait(filp, &work->waiters, poll_table);
- work->waiters_pending = true;
+ poll_wait(filp, &rbwork->waiters, poll_table);
+ rbwork->waiters_pending = true;
}
/*
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8198bfc54b58d9729ab6f6318eb9720a32d40375..c9c8983073485bb3645062760ffc4b0dcef94e9d 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -7293,6 +7293,8 @@ tracing_free_buffer_release(struct inode *inode, struct file *filp)
return 0;
}
+#define TRACE_MARKER_MAX_SIZE 4096
+
static ssize_t
tracing_mark_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *fpos)
@@ -7320,6 +7322,9 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
if ((ssize_t)cnt < 0)
return -EINVAL;
+ if (cnt > TRACE_MARKER_MAX_SIZE)
+ cnt = TRACE_MARKER_MAX_SIZE;
+
meta_size = sizeof(*entry) + 2; /* add '\0' and possible '\n' */
again:
size = cnt + meta_size;
@@ -7328,11 +7333,6 @@ tracing_mark_write(struct file *filp, const char __user *ubuf,
if (cnt < FAULTED_SIZE)
size += FAULTED_SIZE - cnt;
- if (size > TRACE_SEQ_BUFFER_SIZE) {
- cnt -= size - TRACE_SEQ_BUFFER_SIZE;
- goto again;
- }
-
buffer = tr->array_buffer.buffer;
event = __trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
tracing_gen_ctx());
@@ -8393,6 +8393,20 @@ tracing_buffers_read(struct file *filp, char __user *ubuf,
return size;
}
+static int tracing_buffers_flush(struct file *file, fl_owner_t id)
+{
+ struct ftrace_buffer_info *info = file->private_data;
+ struct trace_iterator *iter = &info->iter;
+
+ iter->wait_index++;
+ /* Make sure the waiters see the new wait_index */
+ smp_wmb();
+
+ ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
+
+ return 0;
+}
+
static int tracing_buffers_release(struct inode *inode, struct file *file)
{
struct ftrace_buffer_info *info = file->private_data;
@@ -8404,12 +8418,6 @@ static int tracing_buffers_release(struct inode *inode, struct file *file)
__trace_array_put(iter->tr);
- iter->wait_index++;
- /* Make sure the waiters see the new wait_index */
- smp_wmb();
-
- ring_buffer_wake_waiters(iter->array_buffer->buffer, iter->cpu_file);
-
if (info->spare)
ring_buffer_free_read_page(iter->array_buffer->buffer,
info->spare_cpu, info->spare);
@@ -8625,6 +8633,7 @@ static const struct file_operations tracing_buffers_fops = {
.read = tracing_buffers_read,
.poll = tracing_buffers_poll,
.release = tracing_buffers_release,
+ .flush = tracing_buffers_flush,
.splice_read = tracing_buffers_splice_read,
.unlocked_ioctl = tracing_buffers_ioctl,
.llseek = no_llseek,
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 3e7fa44dc2b24850f8b836f6bd223807fbcf0c48..d8b302d0108302d9ef2debe735c4b7778a217f90 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -1587,12 +1587,11 @@ static enum print_line_t trace_print_print(struct trace_iterator *iter,
{
struct print_entry *field;
struct trace_seq *s = &iter->seq;
- int max = iter->ent_size - offsetof(struct print_entry, buf);
trace_assign_type(field, iter->ent);
seq_print_ip_sym(s, field->ip, flags);
- trace_seq_printf(s, ": %.*s", max, field->buf);
+ trace_seq_printf(s, ": %s", field->buf);
return trace_handle_return(s);
}
@@ -1601,11 +1600,10 @@ static enum print_line_t trace_print_raw(struct trace_iterator *iter, int flags,
struct trace_event *event)
{
struct print_entry *field;
- int max = iter->ent_size - offsetof(struct print_entry, buf);
trace_assign_type(field, iter->ent);
- trace_seq_printf(&iter->seq, "# %lx %.*s", field->ip, max, field->buf);
+ trace_seq_printf(&iter->seq, "# %lx %s", field->ip, field->buf);
return trace_handle_return(&iter->seq);
}