Date: Tue, 9 Jul 2013 09:01:45 +0000 (UTC) From: Andriy Gapon <avg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r253077 - head/sys/kern Message-ID: <201307090901.r6991j64023941@svn.freebsd.org>
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Author: avg Date: Tue Jul 9 09:01:44 2013 New Revision: 253077 URL: http://svnweb.freebsd.org/changeset/base/253077 Log: should_yield: protect from td_swvoltick being uninitialized or too stale The distance between ticks and td_swvoltick should be calculated as an unsigned number. Previously we could end up comparing a negative number with hogticks in which case should_yield() would give incorrect answer. We should probably ensure that td_swvoltick is properly initialized. Sponsored by: HybridCluster MFC after: 5 days Modified: head/sys/kern/kern_synch.c Modified: head/sys/kern/kern_synch.c ============================================================================== --- head/sys/kern/kern_synch.c Tue Jul 9 08:59:39 2013 (r253076) +++ head/sys/kern/kern_synch.c Tue Jul 9 09:01:44 2013 (r253077) @@ -581,7 +581,7 @@ int should_yield(void) { - return (ticks - curthread->td_swvoltick >= hogticks); + return ((unsigned int)(ticks - curthread->td_swvoltick) >= hogticks); } void
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