Messages in this thread Patch in this message | | | Date | Thu, 14 Mar 2013 13:39:31 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 2/2] printk: Provide a wake_up_klogd() off-case |
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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 ;))
--- a/lib/bust_spinlocks.c~printk-provide-a-wake_up_klogd-off-case-fix +++ a/lib/bust_spinlocks.c @@ -8,6 +8,7 @@ */ #include <linux/kernel.h> +#include <linux/printk.h> #include <linux/spinlock.h> #include <linux/tty.h> #include <linux/wait.h> @@ -28,5 +29,3 @@ void __attribute__((weak)) bust_spinlock wake_up_klogd(); } } - - _
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