diff options
| -rw-r--r-- | crypto/pbkdf.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/crypto/pbkdf.c b/crypto/pbkdf.c index 0dd7c3aeaa..2989fc0a40 100644 --- a/crypto/pbkdf.c +++ b/crypto/pbkdf.c @@ -107,7 +107,7 @@ static void *threaded_qcrypto_pbkdf2_count_iters(void *data) size_t nsalt = iters_data->nsalt; size_t nout = iters_data->nout; Error **errp = iters_data->errp; - + size_t scaled = 0; uint64_t ret = -1; g_autofree uint8_t *out = g_new(uint8_t, nout); uint64_t iterations = (1 << 15); @@ -131,7 +131,17 @@ static void *threaded_qcrypto_pbkdf2_count_iters(void *data) delta_ms = end_ms - start_ms; - if (delta_ms == 0) { /* sanity check */ + /* + * For very small 'iterations' values, CPU (or crypto + * accelerator) might be fast enough that the scheduler + * hasn't incremented getrusage() data, or incremented + * it by a very small amount, resulting in delta_ms == 0. + * Once we've scaled 'iterations' x10, 5 times, we really + * should be seeing delta_ms != 0, so sanity check at + * that point. + */ + if (scaled > 5 && + delta_ms == 0) { /* sanity check */ error_setg(errp, "Unable to get accurate CPU usage"); goto cleanup; } else if (delta_ms > 500) { @@ -141,6 +151,7 @@ static void *threaded_qcrypto_pbkdf2_count_iters(void *data) } else { iterations = (iterations * 1000 / delta_ms); } + scaled++; } iterations = iterations * 1000 / delta_ms; |