commit 0caa975190e4d2b19e7b65a0b23a7700522aa5d7

Author: Frank Ch. Eigler <fche@redhat.com>

Date:   Mon Aug 31 11:17:33 2015 -0400

    PR18889 part: improve module-notification related debug tracing

    -DDEBUG_KPROBES -DDEBUG_SYMBOLS -DDEBUG_STP_ON_THE_FLY recommended.

diff --git a/runtime/linux/kprobes.c b/runtime/linux/kprobes.c

index 47eb29a..54c224e 100644

--- a/runtime/linux/kprobes.c

+++ b/runtime/linux/kprobes.c

@@ -567,6 +567,8 @@ stapkp_refresh(const char *modname,

 {

    size_t i;

+   dbug_stapkp("refresh %lu probes with module %s\n", nprobes, modname ?: "?");

+

    for (i = 0; i < nprobes; i++) {

       struct stap_dwarf_probe *sdp = &probes[i];

diff --git a/runtime/transport/symbols.c b/runtime/transport/symbols.c

index fe576c1..9ea2b5b 100644

--- a/runtime/transport/symbols.c

+++ b/runtime/transport/symbols.c

@@ -1,7 +1,7 @@

-/* -*- linux-c -*- 

+/* -*- linux-c -*-

  * symbols.c - stp symbol and module functions

  *

- * Copyright (C) Red Hat Inc, 2006-2012

+ * Copyright (C) Red Hat Inc, 2006-2015

  *

  * This file is part of systemtap, and is free software.  You can

  * redistribute it and/or modify it under the terms of the GNU General

@@ -121,10 +121,26 @@ static unsigned _stp_module_nsections (struct module_sect_attrs *attrs)

 static int _stp_module_notifier (struct notifier_block * nb,

                                  unsigned long val, void *data)

 {

+        struct module *mod = data;

+        struct module_sect_attrs *attrs;

+        unsigned i, nsections;

+

+        (void) attrs;

+        (void) i;

+        (void) nsections;

+

+        if (!mod) { // so as to avoid null pointer checks later

+                WARN_ON (!mod);

+                return NOTIFY_DONE;

+        }

+

+        dbug_sym(1, "module notify %lu %s attrs %p\n",

+                 val, mod->name, mod->sect_attrs);

+

         /* Prior to 2.6.11, struct module contained a module_sections

            attribute vector rather than module_sect_attrs.  Prior to

            2.6.19, module_sect_attrs lacked a number-of-sections

-           field.  Past 3.8, MODULE_STATE_COMING is sent too early to 

+           field.  Past 3.8, MODULE_STATE_COMING is sent too early to

            let us probe module init functions.

            Without CONFIG_KALLSYMS, we don't get any of the

@@ -132,11 +148,6 @@ static int _stp_module_notifier (struct notifier_block * nb,

            that directly? */

 #if defined(CONFIG_KALLSYMS) && LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,11)

-        struct module *mod = data;

-        struct module_sect_attrs *attrs;

-        unsigned i, nsections;

-        WARN_ON (!mod);

-

         if (val == MODULE_STATE_COMING ||

             val == MODULE_STATE_LIVE) {

                 /* A module is arriving or has arrived.  Register all

@@ -145,6 +156,7 @@ static int _stp_module_notifier (struct notifier_block * nb,

                    did the fishie go? */

                 attrs = mod->sect_attrs;

+                dbug_sym(1, "module_sect_attrs: %p\n", attrs);

                 if (attrs == NULL) // until add_sect_attrs(), may be zero

                         return NOTIFY_DONE; // remain ignorant

@@ -153,7 +165,7 @@ static int _stp_module_notifier (struct notifier_block * nb,

                         int init_p = (strstr(attrs->attrs[i].name, "init.") != NULL);

                         int init_gone_p = (val == MODULE_STATE_LIVE); // likely already unloaded

-                        _stp_kmodule_update_address(mod->name, 

+                        _stp_kmodule_update_address(mod->name,

                                                     attrs->attrs[i].name,

                                                     ((init_p && init_gone_p) ? 0 : attrs->attrs[i].address));

                 }

@@ -161,7 +173,7 @@ static int _stp_module_notifier (struct notifier_block * nb,

                 /* Verify build-id. */

                 if (_stp_kmodule_check (mod->name))

                    _stp_kmodule_update_address(mod->name, NULL, 0); /* Pretend it was never here. */

-        }        

+        }

         else if (val == MODULE_STATE_GOING) {

                 /* Unregister all sections. */

                 _stp_kmodule_update_address(mod->name, NULL, 0);

commit 2278079efc01124dd509241f6c6eadbd6e19cb2a

Author: Frank Ch. Eigler <fche@redhat.com>

Date:   Mon Aug 31 17:46:43 2015 -0400

    PR18889 part: module-init notification via module_{load,free} tracepoints

    Investigating RHBZ1257399 et al., we found that module_notifier is

    being called too early after kernel commit #4982223e51.  This

    precludes normal module section-address computation and thus kprobe

    emplacement.  This patch adds hooking into the module_{load,free}

    tracepoints in parallel, because on some kernels (RHEL7.1.Z+) they

    occur at just the right time.

    On the downside, on recent LKML kernels, attaching to those

    tracepoints requires EXPORT_TRACEPOINT_SYMBOL_GPL's, so until that is

    done (or another workaround made), LKML kernels will still miss out on

    module-init probing.

diff --git a/buildrun.cxx b/buildrun.cxx

index d7a431d..6d66b5a 100644

--- a/buildrun.cxx

+++ b/buildrun.cxx

@@ -1,5 +1,5 @@

 // build/run probes

-// Copyright (C) 2005-2014 Red Hat Inc.

+// Copyright (C) 2005-2015 Red Hat Inc.

 //

 // This file is part of systemtap, and is free software.  You can

 // redistribute it and/or modify it under the terms of the GNU General

@@ -377,8 +377,10 @@ compile_pass (systemtap_session& s)

   output_exportconf(s, o, "proc_create_data", "STAPCONF_PROC_CREATE_DATA");

   output_exportconf(s, o, "PDE_DATA", "STAPCONF_PDE_DATA");

   output_autoconf(s, o, "autoconf-module-sect-attrs.c", "STAPCONF_MODULE_SECT_ATTRS", NULL);

-

   output_autoconf(s, o, "autoconf-utrace-via-tracepoints.c", "STAPCONF_UTRACE_VIA_TRACEPOINTS", NULL);

+  output_autoconf(s, o, "autoconf-module-tracepoints.c", "STAPCONF_MODULE_TRACEPOINT", NULL);

+  output_exportconf(s, o, "__tracepoint_module_load", "STAPCONF_MODULE_TRACEPOINT_EXPORT_LOAD");

+  output_exportconf(s, o, "__tracepoint_module_free", "STAPCONF_MODULE_TRACEPOINT_EXPORT_FREE");

   output_autoconf(s, o, "autoconf-task_work-struct.c", "STAPCONF_TASK_WORK_STRUCT", NULL);

   output_autoconf(s, o, "autoconf-vm-area-pte.c", "STAPCONF_VM_AREA_PTE", NULL);

   output_autoconf(s, o, "autoconf-relay-umode_t.c", "STAPCONF_RELAY_UMODE_T", NULL);

diff --git a/runtime/linux/autoconf-module-tracepoints.c b/runtime/linux/autoconf-module-tracepoints.c

new file mode 100644

index 0000000..77b938e

--- /dev/null

+++ b/runtime/linux/autoconf-module-tracepoints.c

@@ -0,0 +1,31 @@

+#include <linux/module.h>

+#include <trace/events/module.h>

+

+// NB: in kernels which do have the requisite pieces, just unconfigured, then

+// everything below will compile just fine, only returning ENOSYS at runtime.

+// To get the compile-time error that autoconf needs, check it directly:

+#ifndef CONFIG_TRACEPOINTS

+#error "CONFIG_TRACEPOINTS is not enabled"

+#endif

+

+// presuming void *data-parametrized tracepoint callback api

+

+void __module_load(void *cb_data, struct module* mod)

+{

+        (void) cb_data;

+        (void) mod;

+	return;

+}

+

+void __module_free(void *cb_data, struct module* mod)

+{

+        (void) cb_data;

+        (void) mod;

+	return;

+}

+

+void __autoconf_func(void)

+{

+	(void) register_trace_module_load(__module_load, NULL);

+        (void) register_trace_module_free(__module_free, NULL);

+}

diff --git a/runtime/transport/symbols.c b/runtime/transport/symbols.c

index 9ea2b5b..4266e5d 100644

--- a/runtime/transport/symbols.c

+++ b/runtime/transport/symbols.c

@@ -125,6 +125,7 @@ static int _stp_module_notifier (struct notifier_block * nb,

         struct module_sect_attrs *attrs;

         unsigned i, nsections;

+        (void) nb;

         (void) attrs;

         (void) i;

         (void) nsections;

@@ -191,6 +192,21 @@ static int _stp_module_notifier (struct notifier_block * nb,

         return NOTIFY_DONE;

 }

+

+#ifdef STAPCONF_MODULE_TRACEPOINT

+/* We just delegate to the canonical notifier function */

+static void _stp_module_load_tp(void *data, struct module* mod)

+{

+        (void) _stp_module_notifier (NULL, MODULE_STATE_COMING, mod);

+        

+}

+static void _stp_module_free_tp(void *data, struct module* mod)

+{

+        (void) _stp_module_notifier (NULL, MODULE_STATE_GOING, mod);

+}

+#endif

+

+

 static int _stp_module_update_self (void)

 {

 	/* Only bother if we need unwinding and have module_sect_attrs.  */

diff --git a/runtime/transport/transport.c b/runtime/transport/transport.c

index 54e9b41..e069a3d 100644

--- a/runtime/transport/transport.c

+++ b/runtime/transport/transport.c

@@ -21,6 +21,23 @@

 #include <linux/delay.h>

 #include <linux/mutex.h>

 #include "../uidgid_compatibility.h"

+#ifdef STAPCONF_MODULE_TRACEPOINT

+#include <trace/events/module.h>

+#endif

+

+/* PR18889: After 3.17, commit #de7b2973903c6, tracepoints are

+   attached by symbol-address rather than by name string.  That means

+   they must be EXPORT_TRACEPOINT_SYMBOL_GPL'd for a tracepoint

+   [un]register operation.  On RHEL7 kernels with out that commit

+   backported, we can do a tracepoint attach even without the exports.  */

+#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,17,0)

+#if defined(STAPCONF_MODULE_TRACEPOINT) && defined(STAPCONF_MODULE_TRACEPOINT_EXPORT_LOAD) && defined(STAPCONF_MODULE_TRACEPOINT_EXPORT_FREE)

+#define STAP_USE_MODULE_TRACEPOINTS

+#endif

+#elif defined(STAPCONF_MODULE_TRACEPOINT)

+#define STAP_USE_MODULE_TRACEPOINTS

+#endif

+

 static int _stp_exit_flag = 0;

@@ -83,6 +100,11 @@ static void systemtap_module_exit(void);

 static int systemtap_module_init(void);

 static int _stp_module_notifier_active = 0;

+#ifdef STAPCONF_MODULE_TRACEPOINT

+/* callbacks in runtime/transport/symbols.c */

+static void _stp_module_load_tp(void *data, struct module* mod);

+static void _stp_module_free_tp(void *data, struct module* mod);

+#endif

 static int _stp_module_notifier (struct notifier_block * nb,

                                  unsigned long val, void *data);

 static struct notifier_block _stp_module_notifier_nb = {

@@ -158,11 +180,30 @@ static void _stp_handle_start(struct _stp_msg_start *st)

                            failed: something nasty has happened, and

                            we want no further probing started.  PR16766 */

                         if (!_stp_module_notifier_active) {

-                                int rc = register_module_notifier(& _stp_module_notifier_nb);

-                                if (rc == 0)

-                                        _stp_module_notifier_active = 1;

-                                else

-                                        _stp_warn ("Cannot register module notifier (%d)\n", rc);

+#ifdef STAP_USE_MODULE_TRACEPOINTS

+                                int rc0 = register_trace_module_load (& _stp_module_load_tp, NULL);

+                                if (rc0)

+                                        _stp_warn ("Cannot register module load tracepoint (%d)\n", rc0);

+                                else {

+                                        int rc1 = register_trace_module_free (& _stp_module_free_tp, NULL);

+                                        if (rc1) {

+                                                _stp_warn ("Cannot register module free tracepoint (%d)\n", rc1);

+                                                unregister_trace_module_load(& _stp_module_load_tp, NULL);

+                                        } else {

+#endif

+                                                int rc = register_module_notifier(& _stp_module_notifier_nb);

+                                                if (rc == 0)

+                                                        _stp_module_notifier_active = 1;

+                                                else {

+                                                        _stp_warn ("Cannot register module notifier (%d)\n", rc);

+#ifdef STAP_USE_MODULE_TRACEPOINTS

+                                                        unregister_trace_module_load(& _stp_module_load_tp, NULL);

+                                                        unregister_trace_module_free(& _stp_module_free_tp, NULL);

+                                                        

+                                                }

+                                        }

+#endif

+                                }

                         }

                 }

@@ -198,7 +239,12 @@ static void _stp_cleanup_and_exit(int send_exit)

 	        /* Unregister the module notifier. */

 	        if (_stp_module_notifier_active) {

-                        int rc = unregister_module_notifier(& _stp_module_notifier_nb);

+                        int rc;

+#ifdef STAP_USE_MODULE_TRACEPOINTS

+                        unregister_trace_module_load(& _stp_module_load_tp, NULL);

+                        unregister_trace_module_free(& _stp_module_free_tp, NULL);

+#endif

+                        rc = unregister_module_notifier(& _stp_module_notifier_nb);

                         if (rc)

                                 _stp_warn("module_notifier unregister error %d", rc);

 	                _stp_module_notifier_active = 0;

commit 2e67c14dad1c661d2ce0b0ed218b371c1af218ba

Author: Frank Ch. Eigler <fche@redhat.com>

Date:   Wed Sep 2 11:16:46 2015 -0400

    PR18889: switch to STP_TRACEPOINT* frontend for kernel tracepoint registration

    jistone kindly reminded that the runtime/stp_tracepoint.[ch] machinery

    allows us to attach to kernel tracepoints, whether on string- or

    tp*-based kernel APIs, and whether or not the tp* objects are

    EXPORT_TRACEPOINT_SYMBOL_GPL'd.  Let's use those; presto we get

    module-init probing back on kernels oldish and newish.

diff --git a/buildrun.cxx b/buildrun.cxx

index 6d66b5a..2ca5933 100644

--- a/buildrun.cxx

+++ b/buildrun.cxx

@@ -379,8 +379,6 @@ compile_pass (systemtap_session& s)

   output_autoconf(s, o, "autoconf-module-sect-attrs.c", "STAPCONF_MODULE_SECT_ATTRS", NULL);

   output_autoconf(s, o, "autoconf-utrace-via-tracepoints.c", "STAPCONF_UTRACE_VIA_TRACEPOINTS", NULL);

   output_autoconf(s, o, "autoconf-module-tracepoints.c", "STAPCONF_MODULE_TRACEPOINT", NULL);

-  output_exportconf(s, o, "__tracepoint_module_load", "STAPCONF_MODULE_TRACEPOINT_EXPORT_LOAD");

-  output_exportconf(s, o, "__tracepoint_module_free", "STAPCONF_MODULE_TRACEPOINT_EXPORT_FREE");

   output_autoconf(s, o, "autoconf-task_work-struct.c", "STAPCONF_TASK_WORK_STRUCT", NULL);

   output_autoconf(s, o, "autoconf-vm-area-pte.c", "STAPCONF_VM_AREA_PTE", NULL);

   output_autoconf(s, o, "autoconf-relay-umode_t.c", "STAPCONF_RELAY_UMODE_T", NULL);

diff --git a/runtime/transport/transport.c b/runtime/transport/transport.c

index e069a3d..db7de46 100644

--- a/runtime/transport/transport.c

+++ b/runtime/transport/transport.c

@@ -1,8 +1,8 @@

-/* -*- linux-c -*- 

+/* -*- linux-c -*-

  * transport.c - stp transport functions

  *

  * Copyright (C) IBM Corporation, 2005

- * Copyright (C) Red Hat Inc, 2005-2014

+ * Copyright (C) Red Hat Inc, 2005-2015

  * Copyright (C) Intel Corporation, 2006

  *

  * This file is part of systemtap, and is free software.  You can

@@ -23,19 +23,7 @@

 #include "../uidgid_compatibility.h"

 #ifdef STAPCONF_MODULE_TRACEPOINT

 #include <trace/events/module.h>

-#endif

-

-/* PR18889: After 3.17, commit #de7b2973903c6, tracepoints are

-   attached by symbol-address rather than by name string.  That means

-   they must be EXPORT_TRACEPOINT_SYMBOL_GPL'd for a tracepoint

-   [un]register operation.  On RHEL7 kernels with out that commit

-   backported, we can do a tracepoint attach even without the exports.  */

-#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,17,0)

-#if defined(STAPCONF_MODULE_TRACEPOINT) && defined(STAPCONF_MODULE_TRACEPOINT_EXPORT_LOAD) && defined(STAPCONF_MODULE_TRACEPOINT_EXPORT_FREE)

-#define STAP_USE_MODULE_TRACEPOINTS

-#endif

-#elif defined(STAPCONF_MODULE_TRACEPOINT)

-#define STAP_USE_MODULE_TRACEPOINTS

+#include "../linux/stp_tracepoint.h"

 #endif

@@ -149,7 +137,7 @@ static void _stp_handle_start(struct _stp_msg_start *st)

         // protect against excessive or premature startup

 	handle_startup = (! _stp_start_called && ! _stp_exit_called);

 	_stp_start_called = 1;

-	

+

 	if (handle_startup) {

 		dbug_trans(1, "stp_handle_start\n");

@@ -180,15 +168,15 @@ static void _stp_handle_start(struct _stp_msg_start *st)

                            failed: something nasty has happened, and

                            we want no further probing started.  PR16766 */

                         if (!_stp_module_notifier_active) {

-#ifdef STAP_USE_MODULE_TRACEPOINTS

-                                int rc0 = register_trace_module_load (& _stp_module_load_tp, NULL);

+#ifdef STAPCONF_MODULE_TRACEPOINT

+                                int rc0 = STP_TRACE_REGISTER(module_load, & _stp_module_load_tp);

                                 if (rc0)

                                         _stp_warn ("Cannot register module load tracepoint (%d)\n", rc0);

                                 else {

-                                        int rc1 = register_trace_module_free (& _stp_module_free_tp, NULL);

+                                        int rc1 = STP_TRACE_REGISTER(module_free, & _stp_module_free_tp);

                                         if (rc1) {

                                                 _stp_warn ("Cannot register module free tracepoint (%d)\n", rc1);

-                                                unregister_trace_module_load(& _stp_module_load_tp, NULL);

+                                                STP_TRACE_UNREGISTER(module_load, & _stp_module_load_tp);

                                         } else {

 #endif

                                                 int rc = register_module_notifier(& _stp_module_notifier_nb);

@@ -196,10 +184,9 @@ static void _stp_handle_start(struct _stp_msg_start *st)

                                                         _stp_module_notifier_active = 1;

                                                 else {

                                                         _stp_warn ("Cannot register module notifier (%d)\n", rc);

-#ifdef STAP_USE_MODULE_TRACEPOINTS

-                                                        unregister_trace_module_load(& _stp_module_load_tp, NULL);

-                                                        unregister_trace_module_free(& _stp_module_free_tp, NULL);

-                                                        

+#ifdef STAPCONF_MODULE_TRACEPOINT

+                                                        STP_TRACE_UNREGISTER(module_load, & _stp_module_load_tp);

+                                                        STP_TRACE_UNREGISTER(module_free, & _stp_module_free_tp);

                                                 }

                                         }

 #endif

@@ -240,9 +227,9 @@ static void _stp_cleanup_and_exit(int send_exit)

 	        /* Unregister the module notifier. */

 	        if (_stp_module_notifier_active) {

                         int rc;

-#ifdef STAP_USE_MODULE_TRACEPOINTS

-                        unregister_trace_module_load(& _stp_module_load_tp, NULL);

-                        unregister_trace_module_free(& _stp_module_free_tp, NULL);

+#ifdef STAPCONF_MODULE_TRACEPOINT

+                        STP_TRACE_UNREGISTER(module_load, & _stp_module_load_tp);

+                        STP_TRACE_UNREGISTER(module_free, & _stp_module_free_tp);

 #endif

                         rc = unregister_module_notifier(& _stp_module_notifier_nb);

                         if (rc)

@@ -380,7 +367,7 @@ static void _stp_ctl_work_callback(unsigned long val)

  *	_stp_transport_close - close ctl and relayfs channels

  *

  *	This is called automatically when the module is unloaded.

- *     

+ *

  */

 static void _stp_transport_close(void)

 {

@@ -397,7 +384,7 @@ static void _stp_transport_close(void)

 /**

  * _stp_transport_init() is called from the module initialization.

- *   It does the bare minimum to exchange commands with staprun 

+ *   It does the bare minimum to exchange commands with staprun

  */

 static int _stp_transport_init(void)

 {

@@ -657,7 +644,7 @@ static struct dentry *_stp_get_module_dir(void)

 static int _stp_transport_fs_init(const char *module_name)

 {

 	struct dentry *root_dir;

-    

+

 	dbug_trans(1, "entry\n");

 	if (module_name == NULL)

 		return -1;

commit 578f5f6f6792fc92d74539a927cd85de5bcbb4dd

Author: Frank Ch. Eigler <fche@redhat.com>

Date:   Wed Sep 2 11:52:31 2015 -0400

    PR18889 testing: already done by modules_out_of_tree.exp

    Ditch bz6503, given that it wasn't reliable.

diff --git a/testsuite/systemtap.base/bz6503.exp b/testsuite/systemtap.base/bz6503.exp

deleted file mode 100644

index 5d4d2d0..0000000

--- a/testsuite/systemtap.base/bz6503.exp

+++ /dev/null

@@ -1,55 +0,0 @@

-# Note that this test is *really* testing the bug fix for pr6503:

-#   permit probes on module .init and __exit functions

-#   <http://sourceware.org/bugzilla/show_bug.cgi?id=6503>

-#

-# Not BZ6503:

-#   ypserve does not work

-#   <https://bugzilla.redhat.com/show_bug.cgi?id=6503>

-#

-# Unfortunately, PR17249 indicates that module-init probes

-# have subsequently broken (due to kernel notification timing

-# changes).

-#

-

-set test bz6503

-

-if {! [installtest_p]} {

-    untested "$test"

-    return

-}

-

-# If we aren't root, make sure the test still succeeds.

-set effective_pid [exec /usr/bin/id -u]

-if {$effective_pid != 0} {

-    set root_cmd "sudo "

-} else {

-    set root_cmd ""

-}

-

-

-# jffs2/ext2/fat/vfat should cover a span of kernels.

-#

-# Note that this test might fail if there is a filesystem of one of

-# these types already mounted.  The filesystem mount will be

-# unaffected (since the module can't be removed).

-spawn stap -t $srcdir/$subdir/bz6503.stp -c "( ($root_cmd /sbin/modprobe jffs2; $root_cmd /sbin/modprobe ext2; $root_cmd /sbin/modprobe fat; $root_cmd /sbin/modprobe vfat); wait; ($root_cmd /sbin/rmmod jffs2; $root_cmd /sbin/rmmod ext2; $root_cmd /sbin/rmmod vfat; $root_cmd /sbin/rmmod fat); wait) 2>/dev/null"

-

-set ok 0

-set ko 0

-expect {

-    -timeout 60

-    timeout { fail "$test (timeout)" }

-    -re {^-----[^\r\n]*\r\n} { exp_continue }

-    -re {^module[^\r\n]*hits:[^\r\n]*\r\n} { incr ok; exp_continue }

-    -re {^WARNING:[\r\n]*\r\n} { incr ko; exp_continue }

-    -re {^ERROR:[\r\n]*\r\n} { incr ko; exp_continue }

-    eof { }

-}

-catch { close} ; catch { wait }

-

-# Mark kernels without module refresh support as xfail

-if {![module_refresh_p]} { setup_xfail *-*-* }

-

-if {$ok > 0 && $ko == 0} then { pass "$test $ok" } else { fail "$test $ok $ko"}

-

-

diff --git a/testsuite/systemtap.base/bz6503.stp b/testsuite/systemtap.base/bz6503.stp

deleted file mode 100644

index 409149f..0000000

--- a/testsuite/systemtap.base/bz6503.stp

+++ /dev/null

@@ -1,5 +0,0 @@

-probe module("jffs2").function("*").call ?,

-      module("ext2").function("*").call ?,

-      module("fat").function("*").call ?,

-      module("vfat").function("*").call ?,

-      never { }