From owner-svn-src-head@freebsd.org Sat Mar 24 13:48:54 2018 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 5CBFDF6EF9D; Sat, 24 Mar 2018 13:48:54 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 0B2476C81E; Sat, 24 Mar 2018 13:48:54 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id E021F7FD4; Sat, 24 Mar 2018 13:48:53 +0000 (UTC) (envelope-from kib@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id w2ODmrmX043384; Sat, 24 Mar 2018 13:48:53 GMT (envelope-from kib@FreeBSD.org) Received: (from kib@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id w2ODmrcC043383; Sat, 24 Mar 2018 13:48:53 GMT (envelope-from kib@FreeBSD.org) Message-Id: <201803241348.w2ODmrcC043383@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: kib set sender to kib@FreeBSD.org using -f From: Konstantin Belousov Date: Sat, 24 Mar 2018 13:48:53 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r331489 - head/sys/vm X-SVN-Group: head X-SVN-Commit-Author: kib X-SVN-Commit-Paths: head/sys/vm X-SVN-Commit-Revision: 331489 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 24 Mar 2018 13:48:54 -0000 Author: kib Date: Sat Mar 24 13:48:53 2018 New Revision: 331489 URL: https://svnweb.freebsd.org/changeset/base/331489 Log: For vm_zone_stats() sysctl handler, do not drain sbuf calling copyout(9) while owning zone lock. Despite old value sysctl buffer is wired, spurious faults might still occur. Note that we still own the uma_rwlock there, but this lock does not participate in sensitive lock orders. Reported and tested by: pho (as part of the larger patch) Sponsored by: The FreeBSD Foundation MFC after: 1 week Modified: head/sys/vm/uma_core.c Modified: head/sys/vm/uma_core.c ============================================================================== --- head/sys/vm/uma_core.c Sat Mar 24 13:18:09 2018 (r331488) +++ head/sys/vm/uma_core.c Sat Mar 24 13:48:53 2018 (r331489) @@ -3692,7 +3692,7 @@ sysctl_vm_zone_stats(SYSCTL_HANDLER_ARGS) { struct uma_stream_header ush; struct uma_type_header uth; - struct uma_percpu_stat ups; + struct uma_percpu_stat *ups; uma_bucket_t bucket; uma_zone_domain_t zdom; struct sbuf sbuf; @@ -3708,6 +3708,7 @@ sysctl_vm_zone_stats(SYSCTL_HANDLER_ARGS) return (error); sbuf_new_for_sysctl(&sbuf, NULL, 128, req); sbuf_clear_flags(&sbuf, SBUF_INCLUDENUL); + ups = malloc((mp_maxid + 1) * sizeof(*ups), M_TEMP, M_WAITOK); count = 0; rw_rlock(&uma_rwlock); @@ -3760,7 +3761,6 @@ sysctl_vm_zone_stats(SYSCTL_HANDLER_ARGS) uth.uth_frees = z->uz_frees; uth.uth_fails = z->uz_fails; uth.uth_sleeps = z->uz_sleeps; - (void)sbuf_bcat(&sbuf, &uth, sizeof(uth)); /* * While it is not normally safe to access the cache * bucket pointers while not on the CPU that owns the @@ -3769,30 +3769,31 @@ sysctl_vm_zone_stats(SYSCTL_HANDLER_ARGS) * accept the possible race associated with bucket * exchange during monitoring. */ - for (i = 0; i < (mp_maxid + 1); i++) { - bzero(&ups, sizeof(ups)); - if (kz->uk_flags & UMA_ZFLAG_INTERNAL) - goto skip; - if (CPU_ABSENT(i)) - goto skip; + for (i = 0; i < mp_maxid + 1; i++) { + bzero(&ups[i], sizeof(*ups)); + if (kz->uk_flags & UMA_ZFLAG_INTERNAL || + CPU_ABSENT(i)) + continue; cache = &z->uz_cpu[i]; if (cache->uc_allocbucket != NULL) - ups.ups_cache_free += + ups[i].ups_cache_free += cache->uc_allocbucket->ub_cnt; if (cache->uc_freebucket != NULL) - ups.ups_cache_free += + ups[i].ups_cache_free += cache->uc_freebucket->ub_cnt; - ups.ups_allocs = cache->uc_allocs; - ups.ups_frees = cache->uc_frees; -skip: - (void)sbuf_bcat(&sbuf, &ups, sizeof(ups)); + ups[i].ups_allocs = cache->uc_allocs; + ups[i].ups_frees = cache->uc_frees; } ZONE_UNLOCK(z); + (void)sbuf_bcat(&sbuf, &uth, sizeof(uth)); + for (i = 0; i < mp_maxid + 1; i++) + (void)sbuf_bcat(&sbuf, &ups[i], sizeof(ups[i])); } } rw_runlock(&uma_rwlock); error = sbuf_finish(&sbuf); sbuf_delete(&sbuf); + free(ups, M_TEMP); return (error); }