Projects / watchdog


The Linux kernel can reset the system if serious problems are detected. This can be implemented via special watchdog hardware, or via a slightly less reliable software-only watchdog inside the kernel. Either way, there needs to be a daemon that tells the kernel the system is working fine. If the daemon stops doing that, the system is reset. watchdog is such a daemon. It opens /dev/watchdog, and keeps writing to it often enough to keep the kernel from resetting, at least once per minute. Each write delays the reboot time another minute. After a minute the watchdog hardware will cause the reset. In the case of a software watchdog, the ability to reboot will depend on the state of the machines and interrupts.


Recent releases

  •  22 Mar 2010 15:09

    Release Notes: This release fixes several bugs and adds some updates, mostly to improve usability in embedded systems. In particular, the default interval was shortened. watchdog also exempts itself from the OOM killer to make sure the system does not get reset if it runs out of memory.

    •  22 Mar 2009 13:50

      Release Notes: There are several bugfixes. The repair binary system has been enhanced to know more about the failing test. Configuration of timeouts is allowed. wd_keepalive accepts all options that watchdog accepts, and does not throw errors on those it does not use itself. watchdog will not close the watchdog device so early when trying a normal shutdown. This ensures a reset even if the system hangs while doing this. This release cleans up the code base for gcc-4.4.

      •  17 Aug 2007 13:02

        Release Notes: This release adds an "another-chance" repair script, applies some changes to the RedHat init script, adds a sysconf script for RedHat, makes wd_keepalive honor the configuration file option, adds a wd_keepalive manpage, makes wd_keepalive not start without a watchdog device, fixes some typos in the watchdog manpage, and updates the Debian files.

        •  22 Feb 2007 13:10

          Release Notes: A nasty quotation bug was fixed.

          •  22 Feb 2007 13:10

            Release Notes: Parsing of the ping-count option was fixed. That nasty ping problem was fixed. A problem in which intervals were 50% too long was fixed. More bugs were fixed. The outstanding problems with wd_keepalive were hopefully fixed. Some documentation about return values of the test binary was added.


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