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author | Bryn M. Reeves <bmr@redhat.com> | 2016-07-06 09:12:51 +0100 |
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committer | Bryn M. Reeves <bmr@redhat.com> | 2016-07-06 09:14:43 +0100 |
commit | 03e03e9c11f5731c225d6cb99a1f36d4d8b699f6 (patch) | |
tree | 75c27570a139199798344578757b3464de24dcfd | |
parent | 5d3b136d38db40a6d26b8a09e7a4b504fa2f85d1 (diff) | |
download | lvm2-03e03e9c11f5731c225d6cb99a1f36d4d8b699f6.tar.gz |
libdm: test for zero interval_ns in _utilization() (Coverity)
It's possible for interval_ns to be zero if the interval is not
set or the clock is misconfigured. Test for this before using the
value as the divisor in the utilisation calculation.
-rw-r--r-- | libdm/libdm-stats.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/libdm/libdm-stats.c b/libdm/libdm-stats.c index 057bbcc7b..c0ef38f4c 100644 --- a/libdm/libdm-stats.c +++ b/libdm/libdm-stats.c @@ -2656,10 +2656,19 @@ static int _utilization(const struct dm_stats *dms, double *util, * for the last interval; do not allow a value > 100% utilization * to be passed to a dm_make_percent() call. We expect to see these * at startup if counters have not been cleared before the first read. + * + * A zero interval_ns is also an error since metrics cannot be + * calculated without a defined interval - return zero and emit a + * backtrace in this case. */ io_nsecs = dm_stats_get_counter(dms, DM_STATS_IO_NSECS, region_id, area_id); + if (!interval_ns) { + *util = 0.0; + return_0; + } + io_nsecs = ((io_nsecs < interval_ns) ? io_nsecs : interval_ns); *util = (double) io_nsecs / (double) interval_ns; |