diff options
Diffstat (limited to 'kernel/trace/ring_buffer.c')
| -rw-r--r-- | kernel/trace/ring_buffer.c | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 2bb96ee80120..c3a2e7509527 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -2642,8 +2642,7 @@ rb_check_timestamp(struct ring_buffer_per_cpu *cpu_buffer, { u64 write_stamp; - WARN_ONCE(info->delta > (1ULL << 59), - KERN_WARNING "Delta way too big! %llu ts=%llu before=%llu after=%llu write stamp=%llu\n%s", + WARN_ONCE(1, "Delta way too big! %llu ts=%llu before=%llu after=%llu write stamp=%llu\n%s", (unsigned long long)info->delta, (unsigned long long)info->ts, (unsigned long long)info->before, @@ -2665,7 +2664,26 @@ static void rb_add_timestamp(struct ring_buffer_per_cpu *cpu_buffer, bool abs = info->add_timestamp & (RB_ADD_STAMP_FORCE | RB_ADD_STAMP_ABSOLUTE); - rb_check_timestamp(cpu_buffer, info); + if (unlikely(info->delta > (1ULL << 59))) { + /* did the clock go backwards */ + if (info->before == info->after && info->before > info->ts) { + /* not interrupted */ + static int once; + + /* + * This is possible with a recalibrating of the TSC. + * Do not produce a call stack, but just report it. + */ + if (!once) { + once++; + pr_warn("Ring buffer clock went backwards: %llu -> %llu\n", + info->before, info->ts); + } + } else + rb_check_timestamp(cpu_buffer, info); + if (!abs) + info->delta = 0; + } *event = rb_add_time_stamp(*event, info->delta, abs); *length -= RB_LEN_TIME_EXTEND; *delta = 0; |