From 3d9f134e77864024d67f27e85d85e2ad12a13dc6 Mon Sep 17 00:00:00 2001 From: Dave Barach Date: Sun, 8 Mar 2020 08:27:19 -0400 Subject: [PATCH] vppinfra: fix corner cases in tw_timer_expire Type: fix Signed-off-by: Dave Barach Change-Id: I4b3ff6e9c8e1d76037b168aeab36dcb5b4482260 --- src/vppinfra/tw_timer_template.c | 23 ++++++++++++++++++++++- 1 file changed, 22 insertions(+), 1 deletion(-) diff --git a/src/vppinfra/tw_timer_template.c b/src/vppinfra/tw_timer_template.c index af2b75a0f57..6b005fd2ff3 100644 --- a/src/vppinfra/tw_timer_template.c +++ b/src/vppinfra/tw_timer_template.c @@ -513,7 +513,7 @@ static inline u32 slow_wheel_index __attribute__ ((unused)); u32 glacier_wheel_index __attribute__ ((unused)); - /* Shouldn't happen */ + /* Called too soon to process new timer expirations? */ if (PREDICT_FALSE (now < tw->next_run_time)) return callback_vector_arg; @@ -525,6 +525,27 @@ static inline /* Remember when we ran, compute next runtime */ tw->next_run_time = (now + tw->timer_interval); + /* First call, or time jumped backwards? */ + if (PREDICT_FALSE + ((tw->last_run_time == 0.0) || (now <= tw->last_run_time))) + { + tw->last_run_time = now; + return callback_vector_arg; + } + + /* + * Refuse to do anything if we're about to process way too many slots. + * Should never come anywhere close to happening, with the possible exception + * of cases involving a large forward jump in the timebase. + */ + if (nticks > (1 << (TW_RING_SHIFT + 1))) + { + clib_warning ("Excessive nticks %u at %.6f last run %.6f", + nticks, now, tw->last_run_time); + tw->last_run_time = now; + return callback_vector_arg; + } + if (callback_vector_arg == 0) { _vec_len (tw->expired_timer_handles) = 0; -- 2.16.6