---------------------------------------------- Original Message From: ""<arjan@fenrus.demon.nl> Subject: Re: Q: deadlock Date: Sun, 10 Mar 2002 11:12:15 GMT >In article <63342002301010163277@antisocial.com> you wrote: >> >> Why can the kernel deadlock when calling e.g copy_to_user while holding a >> spinlock? >> I understand that the function can block, but not that it could result in a >> deadlock. > >you hold the spinlock and schedule. another process >gets scheduled and wants to grab the exact same spinlock..... >grabbing spinlock is busy waiting without scheduling so the >original process never ever gets a chance to release the lock.... lock >doesn't get released -> you busy wait forever > I do not see why this is a problem since spinlocks are SMP only. I thought the scheduler (called e.g implicetly by a timer interrupt) would eventually make the process holding the spinlock runable. Then this process would release the spinlock, and the busy waiting process wold enter the critical region? _____________________________________________ Free email with personality! Over 200 domains! http://www.MyOwnEmail.com -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
