Re: [PATCH] printk: Remove separate printk_sched buffers and use printk buf instead

Joe Perches
2014-05-05T23:33:56Z

On Mon, 2014-05-05 at 19:18 -0400, Steven Rostedt wrote:
> To prevent deadlocks with doing a printk inside the scheduler,
> printk_sched() was created. The issue is that printk has a console_sem
> that it can grab and release. The release does a wake up if there's a
> task pending on the sem, and this wake up grabs the rq locks that is
> held in the scheduler. This leads to a possible deadlock if the wake up
> uses the same rq as the one with the rq lock held already.
[]
> kernel/printk/printk.c | 87 +++++++++++++++++++++++++++++++------------------
[]
> @@ -2440,18 +2470,20 @@
> #define PRINTK_BUF_SIZE 512

Wouldn't this define be unused and shouldn't it be deleted too?