Date: Tue, 2 Jun 2015 08:03:29 +0000 (UTC) From: Hiren Panchasara <hiren@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r283905 - stable/10/usr.sbin/pmcstat Message-ID: <201506020803.t5283TQ0052246@svn.freebsd.org>
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Author: hiren Date: Tue Jun 2 08:03:28 2015 New Revision: 283905 URL: https://svnweb.freebsd.org/changeset/base/283905 Log: MFC: r282866 Fix pmcstat symbol resolution for userland processes. When examining existing processes pmcstat fails to correctly determine the locations of executable sections of the process due to a miscalculated virtual load address. This does not affect the newly launched processes as the same value passed as a "start address" to the pmcstat_image_link() thus nullifying the effect of it. The issue manifests itself in processes not being reported in the pmcstat(8) output and "dubious frames" being reported. Fix it for now by ignoring all the sections except the executable one. This won't fix the issue for objects with multiple executable sections but helps in majority of real world usecases. The real solution would be to modify the MAP-IN event to include the appropriate load address so pmcstat(8) won't have to manually parse object files to try to determine it. PR: 198147, 198148 Submitted by: stas Modified: stable/10/usr.sbin/pmcstat/pmcstat_log.c Directory Properties: stable/10/ (props changed) Modified: stable/10/usr.sbin/pmcstat/pmcstat_log.c ============================================================================== --- stable/10/usr.sbin/pmcstat/pmcstat_log.c Tue Jun 2 07:26:26 2015 (r283904) +++ stable/10/usr.sbin/pmcstat/pmcstat_log.c Tue Jun 2 08:03:28 2015 (r283905) @@ -716,7 +716,8 @@ pmcstat_image_get_elf_params(struct pmcs ph.p_offset); break; case PT_LOAD: - if ((ph.p_offset & (-ph.p_align)) == 0) + if ((ph.p_flags & PF_X) != 0 && + (ph.p_offset & (-ph.p_align)) == 0) image->pi_vaddr = ph.p_vaddr & (-ph.p_align); break; }
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