1 files changed, 19 insertions, 6 deletions

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 7d7a07e9b9e9..0aa75be843a0 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4575,20 +4575,33 @@ static size_t
 tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
 {
         size_t count;
+        int save_len;
         int ret;
 
         /* Seq buffer is page-sized, exactly what we need. */
         for (;;) {
-                count = iter->seq.seq.len;
+                save_len = iter->seq.seq.len;
                 ret = print_trace_line(iter);
-                count = iter->seq.seq.len - count;
-                if (rem < count) {
-                        rem = 0;
-                        iter->seq.seq.len -= count;
+
+                if (trace_seq_has_overflowed(&iter->seq)) {
+                        iter->seq.seq.len = save_len;
                         break;
                 }
+
+                /*
+                 * This should not be hit, because it should only
+                 * be set if the iter->seq overflowed. But check it
+                 * anyway to be safe.
+                 */
                 if (ret == TRACE_TYPE_PARTIAL_LINE) {
-                        iter->seq.seq.len -= count;
+                        iter->seq.seq.len = save_len;
+                        break;
+                }
+
+                count = iter->seq.seq.len - save_len;
+                if (rem < count) {
+                        rem = 0;
+                        iter->seq.seq.len = save_len;
                         break;
                 }