On 2/3/2025 18:35, Guenter Roeck wrote: > On 2/4/25 18:02, liuchao (CR) wrote: > > On 1/27/2025 22:30, Guenter Roeck wrote: > >> On 1/27/25 01:35, liuchao (CR) wrote: > >>> On 1/26/25 21:10, Guenter Roeck wrote: > >>>> On 1/26/25 00:38, Liu Chao wrote: > >>>>> Every time the user echoes 0 > /dev/watchdog0, meaningless > >>>>> critical log is printed. > >>>>> > >>>> > >>>> It is not meaningless, and it will still be displayed after this > >>>> change, making the change pointless. > >>> > >>> The change is not pointless. For example, the softdog driver does > >>> not invoke watchdog_stop or print logs in the watchdog_release. > >>> > >> > >> It seems to me that is a problem in the softdog driver. > >> > >> The change is actually worse than I initially thought. > >> The message is _supposed_ to be displayed if watchdog_stop() is not > >> called while the watchdog is running (i.e., if err == -EBUSY). > >> Otherwise it would not be displayed for real hardware watchdogs which > >> are not stopped because they were running and watchdog_stop() is not > >> called because WDIOF_MAGICCLOSE is set in the driver and the magic > >> release byte was not written. > >> > >> Specifically, the softdog driver has WDIOF_MAGICCLOSE set. It is not > >> supposed to be unloadable (or unloaded) while the watchdog is running. > > > > When echo to /dev/watchdog0, The watchdog_open, watchdog_write, and > > watchdog_release functions are invoked in sequence. Do you mean the > > softdog driver should not call watchdog_release? > > > > After the user opens /dev/watchdog0, the user feeds the watchdog > > through ioctl WDIOC_KEEPALIVE and never closes. Is this the correct usage? > > > > I tried softdog. It works as advertised. Yes, "echo 0 > watchdog0" triggers the > message. > "sudo modprobe -r softdog" then fails with > > modprobe: FATAL: Module softdog is in use. > > and, as expected, one minute later (or whatever the timeout is set to) the > system reboots. > > There is nothing wrong with the message. The softdog _does_ refuse to be > unloaded while running, and it _does_ reboot the system after the timeout > expired. This is all perfectly as expected. The log is not meaningless. Instead, it > tells the user that the system will reboot after the watchdog expired. Which it > does. User creates a process and echoes every time to ensure that the system is normal, the process can be executed properly. Otherwise, the system reboots. So the critical message keeps printing. Is it reasonable to change it to info level? > > Guenter
