From 3d116ad2c21e87d02acb2904a7a4c5def3442ef1 Mon Sep 17 00:00:00 2001 From: Mark Johnston Date: Thu, 17 Dec 2020 17:21:12 +0000 Subject: MFC r368306: sdt: Create providers and probes in separate passes when loading sdt.ko --- sys/cddl/dev/sdt/sdt.c | 56 +++++++++++++++++++++++++++++++++++--------------- 1 file changed, 39 insertions(+), 17 deletions(-) diff --git a/sys/cddl/dev/sdt/sdt.c b/sys/cddl/dev/sdt/sdt.c index 9e3053d90073..3f85099f16d4 100644 --- a/sys/cddl/dev/sdt/sdt.c +++ b/sys/cddl/dev/sdt/sdt.c @@ -271,25 +271,23 @@ 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) { @@ -310,6 +308,20 @@ sdt_kld_load(void *arg __unused, struct linker_file *lf) } } +/* + * 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) { @@ -348,16 +360,21 @@ sdt_kld_unload_try(void *arg __unused, struct linker_file *lf, int *error) } 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); @@ -369,12 +386,17 @@ 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; -- cgit v1.2.3