Re: [PATCH] watchdog: airoha: validate heartbeat module parameter

[Wayen Yan]

Please do not apply the above patch. It introduces a regression:

The patch removes the direct assignment "wdog_dev->timeout = heartbeat"
and relies on watchdog_init_timeout() instead. However, since wdog_dev
is allocated via devm_kzalloc(), timeout is initialized to 0. If the
heartbeat module parameter is invalid and there is no "timeout-sec" DT
property, watchdog_init_timeout() returns -EINVAL and leaves timeout
at 0. When the watchdog is subsequently started, airoha_wdt_start()
writes 0 * wdt_freq = 0 to WDT_TIMER_LOAD_VALUE, causing an immediate
hardware reboot — which is worse than the original overflow bug.

I will send a v2 patch that:
1. Pre-initializes timeout to WDT_HEARTBEAT before calling
   watchdog_init_timeout(), so the safe default is preserved on failure
2. Sets min_timeout = 1 to prevent timeout = 0 via ioctl

Sorry for the noise.

Wayen