lkml.org 
[lkml]   [2013]   [Mar]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH 2/2] printk: Provide a wake_up_klogd() off-case
From
2013/3/14 Andrew Morton <akpm@linux-foundation.org>:
> 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 ;))

Right, I doubt this will ever happen ;-)

Still, thanks for the fix!


\
 
 \ /
  Last update: 2013-03-14 23:41    [W:0.064 / U:0.208 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site