Date: Fri, 15 Jun 2018 21:36:16 +0000 (UTC) From: Gleb Smirnoff <glebius@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r335242 - head/sys/kern Message-ID: <201806152136.w5FLaGCP074334@repo.freebsd.org>
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Author: glebius Date: Fri Jun 15 21:36:16 2018 New Revision: 335242 URL: https://svnweb.freebsd.org/changeset/base/335242 Log: Since 'ticks' is an int, it may wrap around and cr_ticks at a certain counter_rate will be greater than ticks, resulting in counter_ratecheck() failure. To fix this take an absolute value of the difference between ticks and cr_ticks. Reported by: jtl Sponsored by: Netflix Modified: head/sys/kern/subr_counter.c Modified: head/sys/kern/subr_counter.c ============================================================================== --- head/sys/kern/subr_counter.c Fri Jun 15 21:23:03 2018 (r335241) +++ head/sys/kern/subr_counter.c Fri Jun 15 21:36:16 2018 (r335242) @@ -140,7 +140,7 @@ counter_ratecheck(struct counter_rate *cr, int64_t lim val = cr->cr_over; now = ticks; - if (now - cr->cr_ticks >= hz) { + if (abs(now - cr->cr_ticks) >= hz) { /* * Time to clear the structure, we are in the next second. * First try unlocked read, and then proceed with atomic. @@ -151,7 +151,7 @@ counter_ratecheck(struct counter_rate *cr, int64_t lim * Check if other thread has just went through the * reset sequence before us. */ - if (now - cr->cr_ticks >= hz) { + if (abs(now - cr->cr_ticks) >= hz) { val = counter_u64_fetch(cr->cr_rate); counter_u64_zero(cr->cr_rate); cr->cr_over = 0;
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