Messages in this thread | | | From | Paul Gortmaker <> | Date | Thu, 14 Mar 2013 18:45:56 -0400 | Subject | Re: [PATCH 2/2] printk: Provide a wake_up_klogd() off-case |
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On Thu, Mar 14, 2013 at 6:34 PM, Frederic Weisbecker <fweisbec@gmail.com> wrote: > 2013/3/14 Paul Gortmaker <paul.gortmaker@windriver.com>: >> On Thu, Mar 14, 2013 at 4:39 PM, Andrew Morton >> <akpm@linux-foundation.org> wrote: >>> On Thu, 14 Mar 2013 15:26:29 +0100 Frederic Weisbecker <fweisbec@gmail.com> wrote: >>> >>>> wake_up_klogd() is useless when CONFIG_PRINTK=n because >>>> neither printk() nor printk_sched() are in use and there >>>> are actually no waiter on log_wait waitqueue. It should >>>> be a stub in this case for users like bust_spinlocks(). >>>> >>>> Otherwise this results in this warning when CONFIG_PRINTK=n >>>> and CONFIG_IRQ_WORK=n: >>>> >>>> kernel/built-in.o In function `wake_up_klogd': >>>> (.text.wake_up_klogd+0xb4): undefined reference to `irq_work_queue' >>>> >>>> To fix this, provide an off-case for wake_up_klogd() when >>>> CONFIG_PRINTK=n. >>>> >>>> There is much more from console_unlock() and other console >>>> related code in printk.c that should be moved under >>>> CONFIG_PRINTK. But for now, focus on a minimal fix as we passed >>>> the merged window already. >>>> >>>> --- a/include/linux/kernel.h >>>> +++ b/include/linux/kernel.h >>>> @@ -390,7 +390,6 @@ extern struct pid *session_of_pgrp(struct pid *pgrp); >>>> unsigned long int_sqrt(unsigned long); >>>> >>>> extern void bust_spinlocks(int yes); >>>> -extern void wake_up_klogd(void); >>>> extern int oops_in_progress; /* If set, an oops, panic(), BUG() or die() is in progress */ >>>> extern int panic_timeout; >>>> extern int panic_on_oops; >>>> diff --git a/include/linux/printk.h b/include/linux/printk.h >>>> index 1249a54..822171f 100644 >>>> --- a/include/linux/printk.h >>>> +++ b/include/linux/printk.h >>>> @@ -134,6 +134,8 @@ extern int printk_delay_msec; >>>> extern int dmesg_restrict; >>>> extern int kptr_restrict; >>>> >>>> +extern void wake_up_klogd(void); >>>> + >>> >>> Given this, it would be prudent to include printk.h in >>> bust_spinlocks.c. printk.h currently gets included by kernel.h, but >>> that doesn't actually seem necessary - nothing in kernel.h calls >>> printk(). >>> >>> (I pity anyone who tries to remove that include from kernel.h ;)) >> >> Why did you have to say that? Now I'm inclined to poke at it and >> just see how bad it really is when I pull on that loose thread... > > $ git grep "#include <linux/printk.h>" | cut -d: -f1 | uniq | wc -l > 29 > > $ git grep printk | cut -d: -f1 | uniq | wc -l > 6689 > > There is roughly 6689 - 29 = 6660 files to modify :)
That is the worst case scenario. If we start by fixing existing headers that actually reference printk (like linux/fs.h) first, then we shouldn't have to mine down into all those stand-alone C files. At least I think that may possibly be the case.... ;) Remains to be seen at this point.
Paul. --
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