Date: Thu, 10 Nov 2016 11:12:45 +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: r308480 - head/sys/dev/hwpmc Message-ID: <201611101112.uAABCjJt010277@repo.freebsd.org>
next in thread | raw e-mail | index | archive | help
Author: avg Date: Thu Nov 10 11:12:45 2016 New Revision: 308480 URL: https://svnweb.freebsd.org/changeset/base/308480 Log: pmc_process_csw_out: ignore deleted counters I see the fllowing panic on AMD when exiting pmcstat: panic: [pmc,1473] pp_pmcval outside of expected range cpu=2 ri=17 pp_pmcval=fffffffffa529f5b pm_reloadcount=10000 It seems that at least on AMD a performance counter keeps counting after overflowing. When pmcstat exits it sets counters that it used to PMC_STATE_DELETED and waits until their use count goes to zero. amd_intr() wouldn't reload a counter in that state and, thus, a counter would be allowed to overflow. That means that the counter's value would be allowed to go outside the expected range. MFC after: 2 weeks Modified: head/sys/dev/hwpmc/hwpmc_mod.c Modified: head/sys/dev/hwpmc/hwpmc_mod.c ============================================================================== --- head/sys/dev/hwpmc/hwpmc_mod.c Thu Nov 10 10:45:12 2016 (r308479) +++ head/sys/dev/hwpmc/hwpmc_mod.c Thu Nov 10 11:12:45 2016 (r308480) @@ -1431,8 +1431,8 @@ pmc_process_csw_out(struct thread *td) * save the reading. */ - if (pp != NULL && pp->pp_pmcs[ri].pp_pmc != NULL) { - + if (pm->pm_state != PMC_STATE_DELETED && pp != NULL && + pp->pp_pmcs[ri].pp_pmc != NULL) { KASSERT(pm == pp->pp_pmcs[ri].pp_pmc, ("[pmc,%d] pm %p != pp_pmcs[%d] %p", __LINE__, pm, ri, pp->pp_pmcs[ri].pp_pmc));
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201611101112.uAABCjJt010277>