Re: [patch 00/16] timers: Plug debugobject leaks and use del_timer_sync() in exit/teardown

[Julia Lawall <julia.lawall@lip6.fr>]

As far as I could tell, (part of) the issue is that any kind of exit or 
close function should use del_timer_sync, because they could be called 
from a different CPU than the one that started up the timer?

Here is a semantic patch that takes care of the case of simple module_exit 
functions:

@r@
declarer name module_exit;
identifier ex;
@@

module_exit(ex);

@@
identifier r.ex;
@@

ex(...) {
  <...
- del_timer
+ del_timer_sync
    (...)
  ...>
}

The transformations it makes are below.  I haven't had a chance to check 
which results overlap with what Thomas has already sent, but I could look 
into it if this is the right idea.  I guess other kinds of close/exit 
functions would have to be identified manually, to make more rules.

In what circumstance can one be sure that two instructions are executed on 
the same CPU?

julia

diff -u -p a/arch/mips/lasat/picvue_proc.c b/arch/mips/lasat/picvue_proc.c
--- a/arch/mips/lasat/picvue_proc.c
+++ b/arch/mips/lasat/picvue_proc.c
@@ -175,7 +175,7 @@ static void pvc_proc_cleanup(void)
 	remove_proc_entry("scroll", pvc_display_dir);
 	remove_proc_entry(DISPLAY_DIR_NAME, NULL);
 
-	del_timer(&timer);
+	del_timer_sync(&timer);
 }
 
 static int __init pvc_proc_init(void)
diff -u -p a/drivers/tty/serial/mux.c b/drivers/tty/serial/mux.c
--- a/drivers/tty/serial/mux.c
+++ b/drivers/tty/serial/mux.c
@@ -613,7 +613,7 @@ static void __exit mux_exit(void)
 {
 	/* Delete the Mux timer. */
 	if(port_cnt > 0) {
-		del_timer(&mux_timer);
+		del_timer_sync(&mux_timer);
 #ifdef CONFIG_SERIAL_MUX_CONSOLE
 		unregister_console(&mux_console);
 #endif
diff -u -p a/drivers/input/serio/hp_sdc.c b/drivers/input/serio/hp_sdc.c
--- a/drivers/input/serio/hp_sdc.c
+++ b/drivers/input/serio/hp_sdc.c
@@ -984,7 +984,7 @@ static void hp_sdc_exit(void)
 	free_irq(hp_sdc.irq, &hp_sdc);
 	write_unlock_irq(&hp_sdc.lock);
 
-	del_timer(&hp_sdc.kicker);
+	del_timer_sync(&hp_sdc.kicker);
 
 	tasklet_kill(&hp_sdc.task);
 
diff -u -p a/drivers/isdn/sc/init.c b/drivers/isdn/sc/init.c
--- a/drivers/isdn/sc/init.c
+++ b/drivers/isdn/sc/init.c
@@ -390,8 +390,8 @@ static void __exit sc_exit(void)
 		/*
 		 * kill the timers
 		 */
-		del_timer(&(sc_adapter[i]->reset_timer));
-		del_timer(&(sc_adapter[i]->stat_timer));
+		del_timer_sync(&(sc_adapter[i]->reset_timer));
+		del_timer_sync(&(sc_adapter[i]->stat_timer));
 
 		/*
 		 * Tell I4L we're toast
diff -u -p a/drivers/isdn/i4l/isdn_common.c b/drivers/isdn/i4l/isdn_common.c
--- a/drivers/isdn/i4l/isdn_common.c
+++ b/drivers/isdn/i4l/isdn_common.c
@@ -2381,7 +2381,7 @@ static void __exit isdn_exit(void)
 	}
 	isdn_tty_exit();
 	unregister_chrdev(ISDN_MAJOR, "isdn");
-	del_timer(&dev->timer);
+	del_timer_sync(&dev->timer);
 	/* call vfree with interrupts enabled, else it will hang */
 	vfree(dev);
 	printk(KERN_NOTICE "ISDN-subsystem unloaded\n");
diff -u -p a/drivers/isdn/hardware/mISDN/hfcpci.c b/drivers/isdn/hardware/mISDN/hfcpci.c
--- a/drivers/isdn/hardware/mISDN/hfcpci.c
+++ b/drivers/isdn/hardware/mISDN/hfcpci.c
@@ -2352,7 +2352,7 @@ static void __exit
 HFC_cleanup(void)
 {
 	if (timer_pending(&hfc_tl))
-		del_timer(&hfc_tl);
+		del_timer_sync(&hfc_tl);
 
 	pci_unregister_driver(&hfc_driver);
 }
diff -u -p a/drivers/isdn/act2000/module.c b/drivers/isdn/act2000/module.c
--- a/drivers/isdn/act2000/module.c
+++ b/drivers/isdn/act2000/module.c
@@ -796,7 +796,7 @@ static void __exit act2000_exit(void)
 	act2000_card *last;
 	while (card) {
 		unregister_card(card);
-		del_timer(&card->ptimer);
+		del_timer_sync(&card->ptimer);
 		card = card->next;
 	}
 	card = cards;
diff -u -p a/drivers/net/hamradio/yam.c b/drivers/net/hamradio/yam.c
--- a/drivers/net/hamradio/yam.c
+++ b/drivers/net/hamradio/yam.c
@@ -1184,7 +1184,7 @@ static void __exit yam_cleanup_driver(vo
 	struct yam_mcs *p;
 	int i;
 
-	del_timer(&yam_timer);
+	del_timer_sync(&yam_timer);
 	for (i = 0; i < NR_PORTS; i++) {
 		struct net_device *dev = yam_devs[i];
 		if (dev) {
diff -u -p a/drivers/staging/speakup/main.c b/drivers/staging/speakup/main.c
--- a/drivers/staging/speakup/main.c
+++ b/drivers/staging/speakup/main.c
@@ -2218,7 +2218,7 @@ static void __exit speakup_exit(void)
 	unregister_keyboard_notifier(&keyboard_notifier_block);
 	unregister_vt_notifier(&vt_notifier_block);
 	speakup_unregister_devsynth();
-	del_timer(&cursor_timer);
+	del_timer_sync(&cursor_timer);
 	kthread_stop(speakup_task);
 	speakup_task = NULL;
 	mutex_lock(&spk_mutex);
diff -u -p a/drivers/staging/panel/panel.c b/drivers/staging/panel/panel.c
--- a/drivers/staging/panel/panel.c
+++ b/drivers/staging/panel/panel.c
@@ -2298,7 +2298,7 @@ static void __exit panel_cleanup_module(
 	unregister_reboot_notifier(&panel_notifier);
 
 	if (scan_timer.function != NULL)
-		del_timer(&scan_timer);
+		del_timer_sync(&scan_timer);
 
 	if (pprt != NULL) {
 		if (keypad_enabled) {
diff -u -p a/drivers/staging/lustre/lustre/llite/super25.c b/drivers/staging/lustre/lustre/llite/super25.c
--- a/drivers/staging/lustre/lustre/llite/super25.c
+++ b/drivers/staging/lustre/lustre/llite/super25.c
@@ -197,7 +197,7 @@ static void __exit exit_lustre_lite(void
 {
 	ll_xattr_fini();
 	vvp_global_fini();
-	del_timer(&ll_capa_timer);
+	del_timer_sync(&ll_capa_timer);
 	ll_capa_thread_stop();
 	LASSERTF(capa_count[CAPA_SITE_CLIENT] == 0,
 		 "client remaining capa count %d\n",
diff -u -p a/drivers/atm/idt77105.c b/drivers/atm/idt77105.c
--- a/drivers/atm/idt77105.c
+++ b/drivers/atm/idt77105.c
@@ -369,8 +369,8 @@ EXPORT_SYMBOL(idt77105_init);
 static void __exit idt77105_exit(void)
 {
         /* turn off timers */
-        del_timer(&stats_timer);
-        del_timer(&restart_timer);
+        del_timer_sync(&stats_timer);
+        del_timer_sync(&restart_timer);
 }
 
 module_exit(idt77105_exit);
diff -u -p a/drivers/atm/nicstar.c b/drivers/atm/nicstar.c
--- a/drivers/atm/nicstar.c
+++ b/drivers/atm/nicstar.c
@@ -306,7 +306,7 @@ static void __exit nicstar_cleanup(void)
 {
 	XPRINTK("nicstar: nicstar_cleanup() called.\n");
 
-	del_timer(&ns_timer);
+	del_timer_sync(&ns_timer);
 
 	pci_unregister_driver(&nicstar_driver);
 
diff -u -p a/drivers/atm/iphase.c b/drivers/atm/iphase.c
--- a/drivers/atm/iphase.c
+++ b/drivers/atm/iphase.c
@@ -3289,7 +3289,7 @@ static void __exit ia_module_exit(void)
 {
 	pci_unregister_driver(&ia_driver);
 
-        del_timer(&ia_timer);
+        del_timer_sync(&ia_timer);
 }
 
 module_init(ia_module_init);
diff -u -p a/net/hsr/hsr_main.c b/net/hsr/hsr_main.c
--- a/net/hsr/hsr_main.c
+++ b/net/hsr/hsr_main.c
@@ -459,7 +459,7 @@ static int __init hsr_init(void)
 static void __exit hsr_exit(void)
 {
 	unregister_netdevice_notifier(&hsr_nb);
-	del_timer(&prune_timer);
+	del_timer_sync(&prune_timer);
 	hsr_netlink_exit();
 	dev_remove_pack(&hsr_pt);
 }
diff -u -p a/net/atm/mpc.c b/net/atm/mpc.c
--- a/net/atm/mpc.c
+++ b/net/atm/mpc.c
@@ -1492,7 +1492,7 @@ static void __exit atm_mpoa_cleanup(void
 
 	mpc_proc_clean();
 
-	del_timer(&mpc_timer);
+	del_timer_sync(&mpc_timer);
 	unregister_netdevice_notifier(&mpoa_notifier);
 	deregister_atm_ioctl(&atm_ioctl_ops);