diff options
| -rw-r--r-- | kernel/trace/trace.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 73d75cdb7e5b..ecb774cc01ab 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6610,6 +6610,22 @@ static int tracing_wait_pipe(struct file *filp) return 1; } +static bool update_last_data_if_empty(struct trace_array *tr) +{ + if (!(tr->flags & TRACE_ARRAY_FL_LAST_BOOT)) + return false; + + if (!ring_buffer_empty(tr->array_buffer.buffer)) + return false; + + /* + * If the buffer contains the last boot data and all per-cpu + * buffers are empty, reset it from the kernel side. + */ + update_last_data(tr); + return true; +} + /* * Consumer reader. */ @@ -6641,6 +6657,9 @@ tracing_read_pipe(struct file *filp, char __user *ubuf, } waitagain: + if (update_last_data_if_empty(iter->tr)) + return 0; + sret = tracing_wait_pipe(filp); if (sret <= 0) return sret; @@ -8167,6 +8186,9 @@ tracing_buffers_read(struct file *filp, char __user *ubuf, if (ret < 0) { if (trace_empty(iter) && !iter->closed) { + if (update_last_data_if_empty(iter->tr)) + return 0; + if ((filp->f_flags & O_NONBLOCK)) return -EAGAIN; |