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Date: Mon, 2 Mar 2020 06:19:44 -0800 From: Guenter Roeck <linux@...ck-us.net> To: luanshi <zhangliguang@...ux.alibaba.com>, Wim Van Sebroeck <wim@...ux-watchdog.org> Cc: linux-watchdog@...r.kernel.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH] watchdog: sbsa_gwdt: disable watchdog when system panic was trigged by signal WS0 On 3/2/20 12:46 AM, luanshi wrote: > When ARM SBSA Generic Watchdog worked in the two stages mode by setting > module parameter action to 1, when the timeout is reached, the first > signal (WS0) will trigger panic. Before panic, the value of register > SBSA_GWDT_WCS was 0x0, after panic and system startup, the value of > register SBSA_GWDT_WCS was 0x7, status bits SBSA_GWDT_WCS_EN > SBSA_GWDT_WCS_WS0 and SBSA_GWDT_WCS_WS1 were set, this will increase the > refcnt of module sbsa_gwdt by function watchdog_cdev_register because > flag WDOG_HW_RUNNING was set, so we cannot unload the module again. To be > consistent with reboot, watchdog should be disabled when system panic was > trigged by signal(WS0). > > Signed-off-by: Liguang Zhang <zhangliguang@...ux.alibaba.com> > --- > drivers/watchdog/sbsa_gwdt.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/watchdog/sbsa_gwdt.c b/drivers/watchdog/sbsa_gwdt.c > index f0f1e3b..6bee5bb 100644 > --- a/drivers/watchdog/sbsa_gwdt.c > +++ b/drivers/watchdog/sbsa_gwdt.c > @@ -194,6 +194,12 @@ static int sbsa_gwdt_stop(struct watchdog_device *wdd) > > static irqreturn_t sbsa_gwdt_interrupt(int irq, void *dev_id) > { > + struct sbsa_gwdt *gwdt = (struct sbsa_gwdt *)dev_id; > + struct watchdog_device *wdd = &gwdt->wdd; > + > + if (wdd->ops->stop) > + wdd->ops->stop(wdd); > + > panic(WATCHDOG_NAME " timeout"); > > return IRQ_HANDLED; > This prevents the 2nd stage (the actual system reset) from working if the panic call gets stuck and doesn't result in a reboot. I don't think it is a good idea to do that. It effectively disables the second stage. Ultimately, this is a bios problem; the bios/rommon should have stopped the watchdog when rebooting. If you don't want the watchdog to run on startup, you have to add a module parameter to disable the watchdog if it is running at probe time. Guenter
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