Messages in this thread Patch in this message | | | From | Doug Anderson <> | Subject | [PATCH 2/2] watchdog: dw_wdt: keepalive the watchdog at write time | Date | Thu, 7 May 2015 15:09:24 -0700 |
| |
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> --- 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 3fa2f19..ff5d734 100644 --- a/drivers/watchdog/dw_wdt.c +++ b/drivers/watchdog/dw_wdt.c @@ -220,6 +220,7 @@ 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
| |