linux-stable/lib/bust_spinlocks.c
Frederic Weisbecker dc72c32e1f printk: Provide a wake_up_klogd() off-case
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.

[akpm@linux-foundation.org: include printk.h in bust_spinlocks.c]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reported-by: James Hogan <james.hogan@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-03-22 16:41:20 -07:00

31 lines
660 B
C

/*
* lib/bust_spinlocks.c
*
* Provides a minimal bust_spinlocks for architectures which don't have one of their own.
*
* bust_spinlocks() clears any spinlocks which would prevent oops, die(), BUG()
* and panic() information from reaching the user.
*/
#include <linux/kernel.h>
#include <linux/printk.h>
#include <linux/spinlock.h>
#include <linux/tty.h>
#include <linux/wait.h>
#include <linux/vt_kern.h>
#include <linux/console.h>
void __attribute__((weak)) bust_spinlocks(int yes)
{
if (yes) {
++oops_in_progress;
} else {
#ifdef CONFIG_VT
unblank_screen();
#endif
console_unblank();
if (--oops_in_progress == 0)
wake_up_klogd();
}
}