Re: Not getting login prompt after CPU entered into cpu_idle() state
> Here are the final debug statements which we are seeing in the hyper terminal. Can you post the full logs WITHOUT your debug prints. What is the toolchain you are using? > If we load 2.6.10 kernel image, we are getting login prompt in the > hyper terminal on the same Phytec board. You can isolate the problem by writing a small utility(blinky) which would blink some LED on the board and then pass (init = /sbin/blinky) it in your kernel command line. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Not getting login prompt after CPU entered into cpu_idle() state
On Fri, Jul 6, 2012 at 1:02 AM, Jonathan Neuschäfer wrote: > On Fri, Jul 06, 2012 at 12:56:45AM +0700, Mulyadi Santosa wrote: > Only if 0 is already in use. > > But isn't that exec and not open? hm, right, it's execso it should be just launch the init with return value as programmed ( 0?) -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Not getting login prompt after CPU entered into cpu_idle() state
On Fri, Jul 06, 2012 at 12:56:45AM +0700, Mulyadi Santosa wrote: > Hi... > > On Thu, Jul 5, 2012 at 12:12 PM, Srinidhi M wrote: > > .@ <271> ret = 0 : > > /sbin/init > > FYI I absolutely has no hands on experience on this kind of hack, so > this is purely speculation. > > I am thinking, ret=0 when calling /sbin/init? AFAIK, a successful > open() operation should return something bigger than 0 as the file > descriptor. Only if 0 is already in use. But isn't that exec and not open? Thanks, Jonathan ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
Re: Not getting login prompt after CPU entered into cpu_idle() state
Hi... On Thu, Jul 5, 2012 at 12:12 PM, Srinidhi M wrote: > .@ <271> ret = 0 : > /sbin/init FYI I absolutely has no hands on experience on this kind of hack, so this is purely speculation. I am thinking, ret=0 when calling /sbin/init? AFAIK, a successful open() operation should return something bigger than 0 as the file descriptor. Also, init should call /sbin/login or something similar. maybe something is wrong when reading /etc/fstab or anything similar for your kernel? -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
RE: Why can not processes switch in atomic context?
> Date: Wed, 4 Jul 2012 08:12:25 -0700 > Subject: Re: Why can not processes switch in atomic context? > From: dhyla...@gmail.com > To: bu...@live.cn > CC: mobile.parmeni...@gmail.com; kernelnewbies@kernelnewbies.org > > Hi, > > On Wed, Jul 4, 2012 at 3:44 AM, 弋天 卜 wrote: > > > > > > 在 2012-7-3，22:26，"Parmenides" 写道： > > > ...snip... > >> 1. For the spinlock case, it is easy to get if preemption is allowed > >> in critical section, the purpose of protection provided by spinlock > >> can not be achieved readily. > >> > > i think disable preemption in spinlock is not for safe, it is > > For efficiency. Spinlock should exit as soon as possible. > > If tank1 get spinlock and goto sleep for 100 seconds before > > Release spinlock, task2 which requests the same spinlock > > Should wait for 100 seconds, for this example, mutex should be used instead > > of spinlock. > > Unless, of course, the interrupt that fired tried to acquire the > spinlock it preempted, in which case you would have deadlock, even on > an SMP system, if the same processor happened to be used for both. > yes, i think you are right, suppose task1 use spin_lock_irqsave() to get a spinlock, then call schedule() to sleep for a long time, the interrupt on this cpu core will be enabled by kernel, and if there is an interrupt triggered on the same cpu and get the same spinlock, deadlock will happen. ___ Kernelnewbies mailing list Kernelnewbies@kernelnewbies.org http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
