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* [GIT PULL] printk: fixes
@ 2013-03-14 14:26 Frederic Weisbecker
  2013-03-14 14:26 ` [PATCH 1/2] irq_work.h: fix warning when CONFIG_IRQ_WORK=n Frederic Weisbecker
  2013-03-14 14:26 ` [PATCH 2/2] printk: Provide a wake_up_klogd() off-case Frederic Weisbecker
  0 siblings, 2 replies; 8+ messages in thread
From: Frederic Weisbecker @ 2013-03-14 14:26 UTC (permalink / raw)
  To: Ingo Molnar
  Cc: LKML, Frederic Weisbecker, James Hogan, Steven Rostedt,
	Peter Zijlstra, Andrew Morton, Thomas Gleixner, Paul Gortmaker

Ingo,

Please pull the following printk regression fixes from:

git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
	printk/urgent

HEAD: c45a372bdfc0115147afb7eea11313dc057c817e

Thanks.

---
Frederic Weisbecker (1):
  printk: Provide a wake_up_klogd() off-case

James Hogan (1):
  irq_work.h: fix warning when CONFIG_IRQ_WORK=n

 include/linux/irq_work.h |    2 +-
 include/linux/kernel.h   |    1 -
 include/linux/printk.h   |    6 +++
 kernel/printk.c          |   80 ++++++++++++++++++++++-----------------------
 4 files changed, 46 insertions(+), 43 deletions(-)

-- 
1.7.5.4


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH 1/2] irq_work.h: fix warning when CONFIG_IRQ_WORK=n
  2013-03-14 14:26 [GIT PULL] printk: fixes Frederic Weisbecker
@ 2013-03-14 14:26 ` Frederic Weisbecker
  2013-03-14 14:26 ` [PATCH 2/2] printk: Provide a wake_up_klogd() off-case Frederic Weisbecker
  1 sibling, 0 replies; 8+ messages in thread
From: Frederic Weisbecker @ 2013-03-14 14:26 UTC (permalink / raw)
  To: Ingo Molnar
  Cc: LKML, James Hogan, Frederic Weisbecker, Steven Rostedt,
	Peter Zijlstra, Thomas Gleixner, Andrew Morton, Paul Gortmaker

From: James Hogan <james.hogan@imgtec.com>

A randconfig caught repeated compiler warnings when CONFIG_IRQ_WORK=n
due to the definition of a non-inline static function in
<linux/irq_work.h>:

include/linux/irq_work.h +40 : warning: 'irq_work_needs_cpu' defined but not used

Make it inline to supress the warning. This is caused by the following
commit:

Commit 00b42959106a9ca1c2899e591ae4e9a83ad6af05 ("irq_work: Don't stop
the tick with pending works") merged in v3.9-rc1.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---
 include/linux/irq_work.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h
index f5dbce5..6601702 100644
--- a/include/linux/irq_work.h
+++ b/include/linux/irq_work.h
@@ -37,7 +37,7 @@ void irq_work_sync(struct irq_work *work);
 #ifdef CONFIG_IRQ_WORK
 bool irq_work_needs_cpu(void);
 #else
-static bool irq_work_needs_cpu(void) { return false; }
+static inline bool irq_work_needs_cpu(void) { return false; }
 #endif
 
 #endif /* _LINUX_IRQ_WORK_H */
-- 
1.7.5.4


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH 2/2] printk: Provide a wake_up_klogd() off-case
  2013-03-14 14:26 [GIT PULL] printk: fixes Frederic Weisbecker
  2013-03-14 14:26 ` [PATCH 1/2] irq_work.h: fix warning when CONFIG_IRQ_WORK=n Frederic Weisbecker
@ 2013-03-14 14:26 ` Frederic Weisbecker
  2013-03-14 20:39   ` Andrew Morton
  1 sibling, 1 reply; 8+ messages in thread
From: Frederic Weisbecker @ 2013-03-14 14:26 UTC (permalink / raw)
  To: Ingo Molnar
  Cc: LKML, Frederic Weisbecker, James Hogan, Steven Rostedt,
	Peter Zijlstra, Andrew Morton

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.

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>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---
 include/linux/kernel.h |    1 -
 include/linux/printk.h |    6 +++
 kernel/printk.c        |   80 +++++++++++++++++++++++------------------------
 3 files changed, 45 insertions(+), 42 deletions(-)

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 80d3687..79fdd80 100644
--- 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);
+
 void log_buf_kexec_setup(void);
 void __init setup_log_buf(int early);
 #else
@@ -162,6 +164,10 @@ static inline bool printk_timed_ratelimit(unsigned long *caller_jiffies,
 	return false;
 }
 
+static inline void wake_up_klogd(void)
+{
+}
+
 static inline void log_buf_kexec_setup(void)
 {
 }
diff --git a/kernel/printk.c b/kernel/printk.c
index 0b31715..abbdd9e 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -63,8 +63,6 @@ void asmlinkage __attribute__((weak)) early_printk(const char *fmt, ...)
 #define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */
 #define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */
 
-DECLARE_WAIT_QUEUE_HEAD(log_wait);
-
 int console_printk[4] = {
 	DEFAULT_CONSOLE_LOGLEVEL,	/* console_loglevel */
 	DEFAULT_MESSAGE_LOGLEVEL,	/* default_message_loglevel */
@@ -224,6 +222,7 @@ struct log {
 static DEFINE_RAW_SPINLOCK(logbuf_lock);
 
 #ifdef CONFIG_PRINTK
+DECLARE_WAIT_QUEUE_HEAD(log_wait);
 /* the next printk record to read by syslog(READ) or /proc/kmsg */
 static u64 syslog_seq;
 static u32 syslog_idx;
@@ -1957,45 +1956,6 @@ int is_console_locked(void)
 	return console_locked;
 }
 
-/*
- * Delayed printk version, for scheduler-internal messages:
- */
-#define PRINTK_BUF_SIZE		512
-
-#define PRINTK_PENDING_WAKEUP	0x01
-#define PRINTK_PENDING_SCHED	0x02
-
-static DEFINE_PER_CPU(int, printk_pending);
-static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf);
-
-static void wake_up_klogd_work_func(struct irq_work *irq_work)
-{
-	int pending = __this_cpu_xchg(printk_pending, 0);
-
-	if (pending & PRINTK_PENDING_SCHED) {
-		char *buf = __get_cpu_var(printk_sched_buf);
-		printk(KERN_WARNING "[sched_delayed] %s", buf);
-	}
-
-	if (pending & PRINTK_PENDING_WAKEUP)
-		wake_up_interruptible(&log_wait);
-}
-
-static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = {
-	.func = wake_up_klogd_work_func,
-	.flags = IRQ_WORK_LAZY,
-};
-
-void wake_up_klogd(void)
-{
-	preempt_disable();
-	if (waitqueue_active(&log_wait)) {
-		this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
-		irq_work_queue(&__get_cpu_var(wake_up_klogd_work));
-	}
-	preempt_enable();
-}
-
 static void console_cont_flush(char *text, size_t size)
 {
 	unsigned long flags;
@@ -2458,6 +2418,44 @@ static int __init printk_late_init(void)
 late_initcall(printk_late_init);
 
 #if defined CONFIG_PRINTK
+/*
+ * Delayed printk version, for scheduler-internal messages:
+ */
+#define PRINTK_BUF_SIZE		512
+
+#define PRINTK_PENDING_WAKEUP	0x01
+#define PRINTK_PENDING_SCHED	0x02
+
+static DEFINE_PER_CPU(int, printk_pending);
+static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf);
+
+static void wake_up_klogd_work_func(struct irq_work *irq_work)
+{
+	int pending = __this_cpu_xchg(printk_pending, 0);
+
+	if (pending & PRINTK_PENDING_SCHED) {
+		char *buf = __get_cpu_var(printk_sched_buf);
+		printk(KERN_WARNING "[sched_delayed] %s", buf);
+	}
+
+	if (pending & PRINTK_PENDING_WAKEUP)
+		wake_up_interruptible(&log_wait);
+}
+
+static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = {
+	.func = wake_up_klogd_work_func,
+	.flags = IRQ_WORK_LAZY,
+};
+
+void wake_up_klogd(void)
+{
+	preempt_disable();
+	if (waitqueue_active(&log_wait)) {
+		this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
+		irq_work_queue(&__get_cpu_var(wake_up_klogd_work));
+	}
+	preempt_enable();
+}
 
 int printk_sched(const char *fmt, ...)
 {
-- 
1.7.5.4


^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH 2/2] printk: Provide a wake_up_klogd() off-case
  2013-03-14 14:26 ` [PATCH 2/2] printk: Provide a wake_up_klogd() off-case Frederic Weisbecker
@ 2013-03-14 20:39   ` Andrew Morton
  2013-03-14 22:21     ` Frederic Weisbecker
  2013-03-14 22:24     ` Paul Gortmaker
  0 siblings, 2 replies; 8+ messages in thread
From: Andrew Morton @ 2013-03-14 20:39 UTC (permalink / raw)
  To: Frederic Weisbecker
  Cc: Ingo Molnar, LKML, James Hogan, Steven Rostedt, Peter Zijlstra

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();
 	}
 }
-
-
_


^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH 2/2] printk: Provide a wake_up_klogd() off-case
  2013-03-14 20:39   ` Andrew Morton
@ 2013-03-14 22:21     ` Frederic Weisbecker
  2013-03-14 22:24     ` Paul Gortmaker
  1 sibling, 0 replies; 8+ messages in thread
From: Frederic Weisbecker @ 2013-03-14 22:21 UTC (permalink / raw)
  To: Andrew Morton
  Cc: Ingo Molnar, LKML, James Hogan, Steven Rostedt, Peter Zijlstra

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!

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH 2/2] printk: Provide a wake_up_klogd() off-case
  2013-03-14 20:39   ` Andrew Morton
  2013-03-14 22:21     ` Frederic Weisbecker
@ 2013-03-14 22:24     ` Paul Gortmaker
  2013-03-14 22:34       ` Frederic Weisbecker
  1 sibling, 1 reply; 8+ messages in thread
From: Paul Gortmaker @ 2013-03-14 22:24 UTC (permalink / raw)
  To: Andrew Morton
  Cc: Frederic Weisbecker, Ingo Molnar, LKML, James Hogan,
	Steven Rostedt, Peter Zijlstra

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...

P.
--

>
> --- 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();
>         }
>  }
> -
> -
> _
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH 2/2] printk: Provide a wake_up_klogd() off-case
  2013-03-14 22:24     ` Paul Gortmaker
@ 2013-03-14 22:34       ` Frederic Weisbecker
  2013-03-14 22:45         ` Paul Gortmaker
  0 siblings, 1 reply; 8+ messages in thread
From: Frederic Weisbecker @ 2013-03-14 22:34 UTC (permalink / raw)
  To: Paul Gortmaker
  Cc: Andrew Morton, Ingo Molnar, LKML, James Hogan, Steven Rostedt,
	Peter Zijlstra

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 :)

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH 2/2] printk: Provide a wake_up_klogd() off-case
  2013-03-14 22:34       ` Frederic Weisbecker
@ 2013-03-14 22:45         ` Paul Gortmaker
  0 siblings, 0 replies; 8+ messages in thread
From: Paul Gortmaker @ 2013-03-14 22:45 UTC (permalink / raw)
  To: Frederic Weisbecker
  Cc: Andrew Morton, Ingo Molnar, LKML, James Hogan, Steven Rostedt,
	Peter Zijlstra

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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^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2013-03-14 22:46 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-03-14 14:26 [GIT PULL] printk: fixes Frederic Weisbecker
2013-03-14 14:26 ` [PATCH 1/2] irq_work.h: fix warning when CONFIG_IRQ_WORK=n Frederic Weisbecker
2013-03-14 14:26 ` [PATCH 2/2] printk: Provide a wake_up_klogd() off-case Frederic Weisbecker
2013-03-14 20:39   ` Andrew Morton
2013-03-14 22:21     ` Frederic Weisbecker
2013-03-14 22:24     ` Paul Gortmaker
2013-03-14 22:34       ` Frederic Weisbecker
2013-03-14 22:45         ` Paul Gortmaker

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