Add an underflow check to a cwnd error condition.

This commit is contained in:
Mike Perry 2022-07-26 22:28:02 +00:00
parent 7654e12be8
commit 533fe36957

View File

@ -882,10 +882,19 @@ congestion_control_update_circuit_bdp(congestion_control_t *cc,
if (!cc->ewma_rtt_usec) {
uint64_t cwnd = cc->cwnd;
tor_assert_nonfatal(cc->cwnd <= cwnd_max);
/* If the channel is blocked, keep subtracting off the chan_q
* until we hit the min cwnd. */
if (blocked_on_chan) {
cwnd = MAX(cwnd - chan_q, cc->cwnd_min);
/* Cast is fine because we're less than int32 */
if (chan_q >= (int64_t)cwnd) {
log_notice(LD_CIRC,
"Clock stall with large chanq: %d %"PRIu64, chan_q, cwnd);
cwnd = cc->cwnd_min;
} else {
cwnd = MAX(cwnd - chan_q, cc->cwnd_min);
}
cc->blocked_chan = 1;
} else {
cc->blocked_chan = 0;