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-rw-r--r--kernel/trace/trace.c6
-rw-r--r--kernel/trace/trace.h18
-rw-r--r--kernel/trace/trace_kdb.c6
3 files changed, 20 insertions, 10 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index e9cbb96cd99e..a3e1828f24e9 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -8239,12 +8239,8 @@ void ftrace_dump(enum ftrace_dump_mode oops_dump_mode)
cnt++;
- /* reset all but tr, trace, and overruns */
- memset(&iter.seq, 0,
- sizeof(struct trace_iterator) -
- offsetof(struct trace_iterator, seq));
+ trace_iterator_reset(&iter);
iter.iter_flags |= TRACE_FILE_LAT_FMT;
- iter.pos = -1;
if (trace_find_next_entry_inc(&iter) != NULL) {
int ret;
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 851cd1605085..53a917d83c2d 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1820,4 +1820,22 @@ static inline int tracing_alloc_snapshot_instance(struct trace_array *tr)
extern struct trace_iterator *tracepoint_print_iter;
+/*
+ * Reset the state of the trace_iterator so that it can read consumed data.
+ * Normally, the trace_iterator is used for reading the data when it is not
+ * consumed, and must retain state.
+ */
+static __always_inline void trace_iterator_reset(struct trace_iterator *iter)
+{
+ const size_t offset = offsetof(struct trace_iterator, seq);
+
+ /*
+ * Keep gcc from complaining about overwriting more than just one
+ * member in the structure.
+ */
+ memset((char *)iter + offset, 0, sizeof(struct trace_iterator) - offset);
+
+ iter->pos = -1;
+}
+
#endif /* _LINUX_KERNEL_TRACE_H */
diff --git a/kernel/trace/trace_kdb.c b/kernel/trace/trace_kdb.c
index d953c163a079..9f2b85b4d9e4 100644
--- a/kernel/trace/trace_kdb.c
+++ b/kernel/trace/trace_kdb.c
@@ -41,12 +41,8 @@ static void ftrace_dump_buf(int skip_lines, long cpu_file)
kdb_printf("Dumping ftrace buffer:\n");
- /* reset all but tr, trace, and overruns */
- memset(&iter.seq, 0,
- sizeof(struct trace_iterator) -
- offsetof(struct trace_iterator, seq));
+ trace_iterator_reset(&iter);
iter.iter_flags |= TRACE_FILE_LAT_FMT;
- iter.pos = -1;
if (cpu_file == RING_BUFFER_ALL_CPUS) {
for_each_tracing_cpu(cpu) {