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authorLinus Torvalds <torvalds@linux-foundation.org>2019-05-26 13:49:40 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-26 13:49:40 -0700
commitc5b440951a19fdd068090d38dcbe72ea28e5e0d0 (patch)
tree4078aba02a1cac17bdc9fb84238c4f2207187863
parent862f0a3227b337cea11d0488b0345dc2670fc297 (diff)
parent0c97bf863efce63d6ab7971dad811601e6171d2f (diff)
Merge tag 'trace-v5.2-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing warning fix from Steven Rostedt: "Make the GCC 9 warning for sub struct memset go away. GCC 9 now warns about calling memset() on partial structures when it goes across multiple fields. This adds a helper for the place in tracing that does this type of clearing of a structure" * tag 'trace-v5.2-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Silence GCC 9 array bounds warning
-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 2c92b3d9ea30..1c80521fd436 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -8910,12 +8910,8 @@ 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 82c70b63d375..005f08629b8b 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1966,4 +1966,22 @@ static inline void tracer_hardirqs_off(unsigned long a0, unsigned long a1) { }
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 6c1ae6b752d1..cca65044c14c 100644
--- a/kernel/trace/trace_kdb.c
+++ b/kernel/trace/trace_kdb.c
@@ -37,12 +37,8 @@ static void ftrace_dump_buf(int skip_entries, long cpu_file)
if (skip_entries)
kdb_printf("(skipping %d entries)\n", skip_entries);
- /* 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) {