Hi Li, > From: Li RongQing <roy.qing.li@xxxxxxxxx> > > the softdog has static variables which are accessed if its timer is > still running after the driver is unloaded. and lead to crash: > > $modprobe softdog > $echo 1 >/dev/watchdog > $modprobe -r softdog > > CPU 20 Unable to handle kernel paging request at virtual address > Oops[#1]: > CPU: 20 PID: 0 Comm: swapper/20 Not tainted 4.1.13-WR8.0.0.0_standard > ... > Modules linked in: [last unloaded: softdog] > .... > Call Trace: > [<ffffffff801e142c>] cascade+0x34/0xb0 > [<ffffffff801e1964>] run_timer_softirq+0x30c/0x368 > [<ffffffff80181044>] __do_softirq+0x1ec/0x418 > [<ffffffff801815d0>] irq_exit+0x90/0x98 > [<ffffffff8010749c>] plat_irq_dispatch+0xa4/0x140 > [<ffffffff80152740>] ret_from_irq+0x0/0x4 > [<ffffffff801529e0>] __r4k_wait+0x20/0x40 > [<ffffffff801c2278>] cpu_startup_entry+0x2a0/0x368 > [<ffffffff8015fa64>] start_secondary+0x444/0x4d8 > > add the module ref when timer is running to avoid to unload the softdog > module > > Signed-off-by: Li RongQing <roy.qing.li@xxxxxxxxx> > Cc: Guenter Roeck <linux@xxxxxxxxxxxx> > --- > drivers/watchdog/softdog.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/watchdog/softdog.c b/drivers/watchdog/softdog.c > index 0dc5e323d..86ce3f9 100644 > --- a/drivers/watchdog/softdog.c > +++ b/drivers/watchdog/softdog.c > @@ -87,6 +87,7 @@ static struct timer_list watchdog_ticktock = > > static void watchdog_fire(unsigned long data) > { > + module_put(THIS_MODULE); > if (soft_noboot) > pr_crit("Triggered - Reboot ignored\n"); > else if (soft_panic) { > @@ -105,13 +106,16 @@ static void watchdog_fire(unsigned long data) > > static int softdog_ping(struct watchdog_device *w) > { > - mod_timer(&watchdog_ticktock, jiffies+(w->timeout*HZ)); > + if (!mod_timer(&watchdog_ticktock, jiffies+(w->timeout*HZ))) > + __module_get(THIS_MODULE); > return 0; > } > > static int softdog_stop(struct watchdog_device *w) > { > - del_timer(&watchdog_ticktock); > + if (del_timer(&watchdog_ticktock)) > + module_put(THIS_MODULE); > + > return 0; > } > > -- > 2.1.4 > Patch is adde to linux-watchdog-next. Kind regards, Wim. -- To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html