From owner-svn-src-all@freebsd.org Thu Dec 3 17:10:00 2020 Return-Path: Delivered-To: svn-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id D4AC64AB13E; Thu, 3 Dec 2020 17:10:00 +0000 (UTC) (envelope-from markj@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4Cn2QJ5kMRz4Vdw; Thu, 3 Dec 2020 17:10:00 +0000 (UTC) (envelope-from markj@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 B76ED1CE96; Thu, 3 Dec 2020 17:10:00 +0000 (UTC) (envelope-from markj@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 0B3HA0I4009188; Thu, 3 Dec 2020 17:10:00 GMT (envelope-from markj@FreeBSD.org) Received: (from markj@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 0B3HA0Ph009187; Thu, 3 Dec 2020 17:10:00 GMT (envelope-from markj@FreeBSD.org) Message-Id: <202012031710.0B3HA0Ph009187@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: markj set sender to markj@FreeBSD.org using -f From: Mark Johnston Date: Thu, 3 Dec 2020 17:10:00 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r368306 - head/sys/cddl/dev/sdt X-SVN-Group: head X-SVN-Commit-Author: markj X-SVN-Commit-Paths: head/sys/cddl/dev/sdt X-SVN-Commit-Revision: 368306 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 03 Dec 2020 17:10:00 -0000 Author: markj Date: Thu Dec 3 17:10:00 2020 New Revision: 368306 URL: https://svnweb.freebsd.org/changeset/base/368306 Log: sdt: Create providers and probes in separate passes when loading sdt.ko The sdt module's load handler iterates over SDT linker sets for the kernel and all loaded modules to create probes and providers defined by SDT(9). Probes in one module may belong to a provider in a different module, but when a probe is created we assume that the provider is already defined. To maintain this invariant, modify the load handler to perform two separate passes over loaded modules: one to define providers and the other to define probes. The problem manifests when loading linux.ko, which depends on linux_common.ko, which defines providers used by probes defined in linux.ko. Reported by: gallatin MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Modified: head/sys/cddl/dev/sdt/sdt.c Modified: head/sys/cddl/dev/sdt/sdt.c ============================================================================== --- head/sys/cddl/dev/sdt/sdt.c Thu Dec 3 16:54:59 2020 (r368305) +++ head/sys/cddl/dev/sdt/sdt.c Thu Dec 3 17:10:00 2020 (r368306) @@ -272,26 +272,24 @@ sdt_destroy(void *arg, dtrace_id_t id, void *parg) { } -/* - * Called from the kernel linker when a module is loaded, before - * dtrace_module_loaded() is called. This is done so that it's possible to - * register new providers when modules are loaded. The DTrace framework - * explicitly disallows calling into the framework from the provide_module - * provider method, so we cannot do this there. - */ static void -sdt_kld_load(void *arg __unused, struct linker_file *lf) +sdt_kld_load_providers(struct linker_file *lf) { struct sdt_provider **prov, **begin, **end; - struct sdt_probe **probe, **p_begin, **p_end; - struct sdt_argtype **argtype, **a_begin, **a_end; if (linker_file_lookup_set(lf, "sdt_providers_set", &begin, &end, NULL) == 0) { for (prov = begin; prov < end; prov++) sdt_create_provider(*prov); } +} +static void +sdt_kld_load_probes(struct linker_file *lf) +{ + struct sdt_probe **probe, **p_begin, **p_end; + struct sdt_argtype **argtype, **a_begin, **a_end; + if (linker_file_lookup_set(lf, "sdt_probes_set", &p_begin, &p_end, NULL) == 0) { for (probe = p_begin; probe < p_end; probe++) { @@ -311,7 +309,21 @@ sdt_kld_load(void *arg __unused, struct linker_file *l } } +/* + * Called from the kernel linker when a module is loaded, before + * dtrace_module_loaded() is called. This is done so that it's possible to + * register new providers when modules are loaded. The DTrace framework + * explicitly disallows calling into the framework from the provide_module + * provider method, so we cannot do this there. + */ static void +sdt_kld_load(void *arg __unused, struct linker_file *lf) +{ + sdt_kld_load_providers(lf); + sdt_kld_load_probes(lf); +} + +static void sdt_kld_unload_try(void *arg __unused, struct linker_file *lf, int *error) { struct sdt_provider *prov, **curr, **begin, **end, *tmp; @@ -349,16 +361,21 @@ sdt_kld_unload_try(void *arg __unused, struct linker_f } static int -sdt_linker_file_cb(linker_file_t lf, void *arg __unused) +sdt_load_providers_cb(linker_file_t lf, void *arg __unused) { + sdt_kld_load_providers(lf); + return (0); +} - sdt_kld_load(NULL, lf); - +static int +sdt_load_probes_cb(linker_file_t lf, void *arg __unused) +{ + sdt_kld_load_probes(lf); return (0); } static void -sdt_load() +sdt_load(void) { TAILQ_INIT(&sdt_prov_list); @@ -370,12 +387,17 @@ sdt_load() sdt_kld_unload_try_tag = EVENTHANDLER_REGISTER(kld_unload_try, sdt_kld_unload_try, NULL, EVENTHANDLER_PRI_ANY); - /* Pick up probes from the kernel and already-loaded linker files. */ - linker_file_foreach(sdt_linker_file_cb, NULL); + /* + * Pick up probes from the kernel and already-loaded linker files. + * Define providers in a separate pass since a linker file may be using + * providers defined in a file that appears later in the list. + */ + linker_file_foreach(sdt_load_providers_cb, NULL); + linker_file_foreach(sdt_load_probes_cb, NULL); } static int -sdt_unload() +sdt_unload(void) { struct sdt_provider *prov, *tmp; int ret;