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-rw-r--r--src/or/circuitstats.c20
1 files changed, 18 insertions, 2 deletions
diff --git a/src/or/circuitstats.c b/src/or/circuitstats.c
index 418acc0024..735b3f0fc2 100644
--- a/src/or/circuitstats.c
+++ b/src/or/circuitstats.c
@@ -753,11 +753,23 @@ circuit_build_times_get_xm(circuit_build_times_t *cbt)
histogram[nth_max_bin[n]]);
}
- /* The following assert is safe, because we don't get called when we
- * haven't observed at least CBT_MIN_MIN_CIRCUITS_TO_OBSERVE circuits. */
+ /* bin_counts can become zero if all of our last CBT_NCIRCUITS_TO_OBSERVE
+ * circuits were abandoned before they completed. This shouldn't happen,
+ * though. We should have reset/re-learned a lower timeout first. */
+ if (bin_counts == 0) {
+ ret = 0;
+ log_warn(LD_CIRC,
+ "No valid circuit build time data out of %d times, %u modes, "
+ "have_timeout=%d, %lfms", cbt->total_build_times, num_modes,
+ cbt->have_computed_timeout, cbt->timeout_ms);
+ goto done;
+ }
+
tor_assert(bin_counts > 0);
ret /= bin_counts;
+
+ done:
tor_free(histogram);
tor_free(nth_max_bin);
@@ -1043,6 +1055,10 @@ circuit_build_times_update_alpha(circuit_build_times_t *cbt)
* and less frechet-like. */
cbt->Xm = circuit_build_times_get_xm(cbt);
+ /* If Xm came back 0, then too many circuits were abandoned. */
+ if (cbt->Xm == 0)
+ return 0;
+
tor_assert(cbt->Xm > 0);
for (i=0; i< CBT_NCIRCUITS_TO_OBSERVE; i++) {