On Fri, 2011-01-07 at 13:05 +0530, Rajat Sharma wrote: > As I remember timer interrupt as well is an NMI so, it is possible > (although not advised) to call schedule function while holding > spinlock on same core. > > spin_lock_irqsave(); > schedule(); > spin_lock_irqrestore(); > > however if you have debugging options turned on like > CONFIG_DEBUG_SPINLOCK, you may likely get kernel warning for > 'scheduling in atomic context'. > > Then what can happen if this core is allowed to switched to new > process? Consider the case where new process as well tries to aquire > same spin_lock() which new process can not aquire and start spinning > for the lock for ever :). Likewise, other cores will also get locked > down. > > However stil you can detect softlockup through NMI watchdog. Sorry if I am building up the confusion here. But as Dave Hylands initially mentioned, there will be no timer interrupt. So shouldn't the NMI watchdog get triggered then? No interrupts -> system freeze -> NMI Wdt reboot. http://slacksite.com/slackware/nmi.html > > Rajat -- Thanks, Nilesh _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
