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-rw-r--r--kernel/trace/trace.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index b38a4bb4054..6a1c76bb56b 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2439,7 +2439,6 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
if (sret != -EBUSY)
return sret;
- sret = 0;
trace_seq_reset(&iter->seq);
@@ -2450,6 +2449,8 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
goto out;
}
+waitagain:
+ sret = 0;
while (trace_empty(iter)) {
if ((filp->f_flags & O_NONBLOCK)) {
@@ -2556,8 +2557,13 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
sret = trace_seq_to_user(&iter->seq, ubuf, cnt);
if (iter->seq.readpos >= iter->seq.len)
trace_seq_reset(&iter->seq);
+
+ /*
+ * If there was nothing to send to user, inspite of consuming trace
+ * entries, go back to wait for more entries.
+ */
if (sret == -EBUSY)
- sret = 0;
+ goto waitagain;
out:
mutex_unlock(&trace_types_lock);