Commit 6549de1f authored by Steven Rostedt (VMware)'s avatar Steven Rostedt (VMware)
Browse files

ring-buffer: Add a little more information and a WARN when time stamp going backwards is detected 



When the CONFIG_RING_BUFFER_VALIDATE_TIME_DELTAS is enabled, and the time
stamps are detected as not being valid, it reports information about the
write stamp, but does not show the before_stamp which is still useful
information. Also, it should give a warning once, such that tests detect
this happening.

Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 6f6be606

kernel/trace/ring_buffer.c

+7 −3
Original line number Diff line number Diff line
@@ -3318,9 +3318,13 @@ static void check_buffer(struct ring_buffer_per_cpu *cpu_buffer, 
			goto out;

		}

		atomic_inc(&cpu_buffer->record_disabled);

		pr_warn("[CPU: %d]TIME DOES NOT MATCH expected:%lld actual:%lld delta:%lld after:%lld\n",

		/* There's some cases in boot up that this can happen */

		WARN_ON_ONCE(system_state != SYSTEM_BOOTING);

		pr_warn("[CPU: %d]TIME DOES NOT MATCH expected:%lld actual:%lld delta:%lld before:%lld after:%lld%s\n",

			cpu_buffer->cpu,

		       ts + info->delta, info->ts, info->delta, info->after);

			ts + info->delta, info->ts, info->delta,

			info->before, info->after,

			full ? " (full)" : "");

		dump_buffer_page(bpage, info, tail);

		atomic_dec(&ts_dump);

		/* Do not re-enable checking */