Author: cperciva
Date: Sun Nov 28 18:59:52 2010
New Revision: 216015
URL: http://svn.freebsd.org/changeset/base/216015
Log:
MFC r215665,r215732: Don't lose seconds to integer overflow if we go more
than one second between calls to tc_windup.
Modified:
stable/8/sys/kern/kern_tc.c
Directory Properties:
stable/8/sys/ (props changed)
stable/8/sys/amd64/include/xen/ (props changed)
stable/8/sys/cddl/contrib/opensolaris/ (props changed)
stable/8/sys/contrib/dev/acpica/ (props changed)
stable/8/sys/contrib/pf/ (props changed)
Modified: stable/8/sys/kern/kern_tc.c
==============================================================================
--- stable/8/sys/kern/kern_tc.c Sun Nov 28 18:53:57 2010 (r216014)
+++ stable/8/sys/kern/kern_tc.c Sun Nov 28 18:59:52 2010 (r216015)
@@ -440,6 +440,16 @@ tc_windup(void)
ncount = 0;
th->th_offset_count += delta;
th->th_offset_count &= th->th_counter->tc_counter_mask;
+ while (delta > th->th_counter->tc_frequency) {
+ /* Eat complete unadjusted seconds. */
+ delta -= th->th_counter->tc_frequency;
+ th->th_offset.sec++;
+ }
+ if ((delta > th->th_counter->tc_frequency / 2) &&
+ (th->th_scale * delta < ((uint64_t)1 << 63))) {
+ /* The product th_scale * delta just barely overflows. */
+ th->th_offset.sec++;
+ }
bintime_addx(&th->th_offset, th->th_scale * delta);
/*
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