[PATCH 3.10 101/319] fix memory leaks in tracing_buffers_splice_read()

[Willy Tarreau]

From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

commit 1ae2293dd6d2f5c823cf97e60b70d03631cd622f upstream.

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Willy Tarreau <w@xxxxxx>
---
 kernel/trace/trace.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index eff26a9..4ff36f7 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -5168,11 +5168,6 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
 	}
 #endif
 
-	if (splice_grow_spd(pipe, &spd)) {
-		ret = -ENOMEM;
-		goto out;
-	}
-
 	if (*ppos & (PAGE_SIZE - 1)) {
 		ret = -EINVAL;
 		goto out;
@@ -5186,6 +5181,11 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
 		len &= PAGE_MASK;
 	}
 
+	if (splice_grow_spd(pipe, &spd)) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
  again:
 	trace_access_lock(iter->cpu_file);
 	entries = ring_buffer_entries_cpu(iter->trace_buffer->buffer, iter->cpu_file);
@@ -5241,21 +5241,22 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos,
 	if (!spd.nr_pages) {
 		if ((file->f_flags & O_NONBLOCK) || (flags & SPLICE_F_NONBLOCK)) {
 			ret = -EAGAIN;
-			goto out;
+			goto out_shrink;
 		}
 		mutex_unlock(&trace_types_lock);
 		ret = iter->trace->wait_pipe(iter);
 		mutex_lock(&trace_types_lock);
 		if (ret)
-			goto out;
+			goto out_shrink;
 		if (signal_pending(current)) {
 			ret = -EINTR;
-			goto out;
+			goto out_shrink;
 		}
 		goto again;
 	}
 
 	ret = splice_to_pipe(pipe, &spd);
+out_shrink:
 	splice_shrink_spd(&spd);
 out:
 	mutex_unlock(&trace_types_lock);
-- 
2.8.0.rc2.1.gbe9624a