On Mon, 2008-08-11 at 08:59 +0800, Huang Ying wrote: > On Fri, 2008-08-08 at 12:13 +0200, Peter Zijlstra wrote: > > On Fri, 2008-08-08 at 14:52 +0800, Huang Ying wrote: > > > Replace local_irq_disable() with raw_local_irq_disable() to prevent > > > lockdep complain. > > Uhhm, please provide more information - just using raw_* to silence > > lockdep is generally the wrong thing to do. > > In traditional kexec, the new kernel will replace current one, so the > irq is simply disabled. But now jumping back from kexeced kernel is > supported, so the irq should be enabled again. > > The code sequence of irq during kexec jump is as follow: > > local_irq_disable(); /* in kernel_kexec() */ > local_irq_disable(); /* in machine_kexec() */ > local_irq_enable(); /* in kernel_kexec() */ > > The disable and enable is not match. Maybe another method is to use > local_irq_save(), local_irq_restore() pair in machine_kexec(), so the > disable and enable is matched. And its the machine kernel's lockdep instance that goes complain? whichever annotation gets used - and I think I can agree that raw_* might be approriate there, this should be accompanied with a rather elaborate changelog and preferably a comment in the code too. Without such we'll be wondering in the years to come WTH happens here.
