Messages in this thread Patch in this message | | | From | Doug Anderson <> | Subject | [PATCH v2 2/2] watchdog: dw_wdt: keepalive the watchdog at write time | Date | Thu, 7 May 2015 21:27:45 -0700 |
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If you've got code that does this in a tight loop 1. Open watchdog 2. Send 'expect close' 3. Close watchdog ...you'll eventually trigger a watchdog reset. You can reproduce this by using daisydog (1) and running: while true; do daisydog -c > /dev/null; done
The problem is that each time you write to the watchdog for 'expect close' it moves the timer .5 seconds out. The timer thus never fires and never pats the watchdog for you.
1: http://git.chromium.org/gitweb/?p=chromiumos/third_party/daisydog.git
Signed-off-by: Doug Anderson <dianders@chromium.org> Reviewed-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Jisheng Zhang <jszhang@marvell.com> --- Changes in v2: None
drivers/watchdog/dw_wdt.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c index a284abd..6ea0634 100644 --- a/drivers/watchdog/dw_wdt.c +++ b/drivers/watchdog/dw_wdt.c @@ -215,6 +215,7 @@ static ssize_t dw_wdt_write(struct file *filp, const char __user *buf, } dw_wdt_set_next_heartbeat(); + dw_wdt_keepalive(); mod_timer(&dw_wdt.timer, jiffies + WDT_TIMEOUT); return len; -- 2.2.0.rc0.207.ga3a616c
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