From 55ea4cf403800af2ce6b125bc3d853117e0c0456 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Fri, 27 Nov 2020 11:20:58 -0500 Subject: ring-buffer: Update write stamp with the correct ts The write stamp, used to calculate deltas between events, was updated with the stale "ts" value in the "info" structure, and not with the updated "ts" variable. This caused the deltas between events to be inaccurate, and when crossing into a new sub buffer, had time go backwards. Link: https://lkml.kernel.org/r/20201124223917.795844-1-elavila@google.com Cc: stable@vger.kernel.org Fixes: a389d86f7fd09 ("ring-buffer: Have nested events still record running time stamp") Reported-by: "J. Avila" Tested-by: Daniel Mentz Tested-by: Will McVicker Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ring_buffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/trace/ring_buffer.c') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index dc83b3fa9fe7..bccaf88d3706 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -3291,7 +3291,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, /* Nothing came after this event between C and E */ info->delta = ts - info->after; (void)rb_time_cmpxchg(&cpu_buffer->write_stamp, - info->after, info->ts); + info->after, ts); info->ts = ts; } else { /* -- cgit v1.2.3-59-g8ed1b