On Sat, 14 Oct 2017 18:21:29 +0900 Sergey Senozhatsky <sergey.senozhat...@gmail.com> wrote:
> On (10/11/17 12:46), Steven Rostedt wrote: > > From: Steven Rostedt (VMware) <rost...@goodmis.org> > > > > The variable printk_safe_irq_ready is set and never cleared at system > > boot up, when there's only one CPU active. It is set before other > > CPUs come on line. Also, it is extremely unlikely that an NMI would > > trigger this early in boot up (which I wonder why we even have this > > variable at all). > > it's not only NMI related, printk() recursion can happen at any stages, > including... um... wait a second. ... including the "before we set up > per-CPU areas" stage? hmm... smells like a bug? I think this was just being overly paranoid. > > do we need to move per-CPU printk_safe buffers out of per-CPU and turn > it into a global static buffer? like logbuf, and just give every CPU a > starting offset of its printk_safe_logbuf part. > > IOW, > > char printk_safe_logbuf[number of cpus * sizeof printk safe buffer]; > > cpu0 offset 0, up to sizeof printk safe buffer > cpu1 offset sizeof printk safe buffer, up to 2 * sizeof printk safe buffer Let's not make this any more complicated than it has to be. > > etc. > > or... at least. avoid stoing to per-CPU printk-safe/printk-nmi buffers > unless we've got per-CPU areas set up? or am I hallucinating? We can keep the flag as is, it's highly unlikely to be a problem. -- Steve
