On 10/27/2011 09:30 PM, Don Zickus wrote: > Hi, > > I was assisting a customer the other day debugging a kdump[1] problem, when we > noticed the real problem was the hardware watchdog was firing and > rebooting the box. > > Of course, this can be inconvienant if the panic happens right before the > watchdog is supposed to be kicked, leading to a spontaneous reboot before > the second kernel finishes booting and loading the watchdog module. > > I was trying to think of a way to solve this and thought, one way to > minimize the problem is to kick the watchdog before we jump into the kdump > kernel. Another way is to disable the watchdog entirely, but that doesn't > work on all hardware I believe. > > Anyway, I was posting on the watchdog mailing list to see if anyone had any > ideas that might help. And if my above idea to kick the watchdog before > jumping into the kdump kernel seems ok, then an api would need to be > developed. > > I am willing to do any coding and testing necessary, but before I did, I > wanted help to get a direction to go in first. > > Thoughts? Seems like the appropriate thing to do is to call all the reboot notifiers that each watchdog registers. Since one is not doingn a full SYS_RESTART (SYS_DOWN) though, i.e. not running through the BIOS code again, it might be worth having a different SYS_JUMP code in notifier.h that would allow you to kick rather than stop the watchdogs as the reboot notifiers generally do at the moment. I think it would be important not to stop the watchdog if possible, given the large amount of logic that's going to be executed after the jump. cheers, P?draig.
