The dw_wdt watchdog driver supports a single DesignWare watchdog device using a statically allocated variable 'dw_wdt' to manage it, but there are some bits of hardware containing two such devices. If the "probe" is called for more than one device, the 'dw_wdt' variable gets clobbered, generally resulting in a kernel crash. Change it to reject additional probed devices. We probably don't expect the "remove" function to get called, but if it does, make sure the Linux timer used by device gets unqueued. The timer also gets unqueued if the watchdog device is closed by the user process unexpectedly. However, this is not currently done asynchronously and the timer function normally requeues the timer. If it manages to requeue the timer, the next call of the timer function will behave as though the close was expected and continue patting the dog every half a second when it should have stopped doing so. Unqueue the timer synchronously to avoid that. NOTE: There is another potential problem that I haven't bothered to fix. If the "remove" function is called while the watchdog device is still open, any in-progress or future file operations are likely to screw things up. 1) watchdog: dw_wdt: prepare for more atomic bits 2) watchdog: dw_wdt: reject additional device probes 3) watchdog: dw_wdt: only unregister restart handler if registered 4) watchdog: dw_wdt: unqueue timer on device removal 5) watchdog: dw_wdt: unqueue timer synchronously on unexpected close drivers/watchdog/dw_wdt.c | 46 +++++++++++++++++++++++++++++++++++----------- 1 file changed, 35 insertions(+), 11 deletions(-) -- 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
