diff options
| -rw-r--r-- | kernel/trace/trace.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index ab5cbcae43a..57155dc5353 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -346,6 +346,9 @@ ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt) int len; int ret; + if (!cnt) + return 0; + if (s->len <= s->readpos) return -EBUSY; @@ -353,9 +356,11 @@ ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt) if (cnt > len) cnt = len; ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt); - if (ret) + if (ret == cnt) return -EFAULT; + cnt -= ret; + s->readpos += len; return cnt; } @@ -3049,6 +3054,9 @@ tracing_buffers_read(struct file *filp, char __user *ubuf, ssize_t ret; size_t size; + if (!count) + return 0; + /* Do we have previous read data to read? */ if (info->read < PAGE_SIZE) goto read; @@ -3073,8 +3081,10 @@ read: size = count; ret = copy_to_user(ubuf, info->spare + info->read, size); - if (ret) + if (ret == size) return -EFAULT; + size -= ret; + *ppos += size; info->read += size; |