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
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 <[email protected]>
Cc: James Hogan <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Andrew Morton <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
---
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
From: James Hogan <[email protected]>
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 <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Paul Gortmaker <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
---
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
On Thu, 14 Mar 2013 15:26:29 +0100 Frederic Weisbecker <[email protected]> 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();
}
}
-
-
_
2013/3/14 Andrew Morton <[email protected]>:
> On Thu, 14 Mar 2013 15:26:29 +0100 Frederic Weisbecker <[email protected]> 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!
On Thu, Mar 14, 2013 at 4:39 PM, Andrew Morton
<[email protected]> wrote:
> On Thu, 14 Mar 2013 15:26:29 +0100 Frederic Weisbecker <[email protected]> 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 [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
2013/3/14 Paul Gortmaker <[email protected]>:
> On Thu, Mar 14, 2013 at 4:39 PM, Andrew Morton
> <[email protected]> wrote:
>> On Thu, 14 Mar 2013 15:26:29 +0100 Frederic Weisbecker <[email protected]> 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 :)
On Thu, Mar 14, 2013 at 6:34 PM, Frederic Weisbecker <[email protected]> wrote:
> 2013/3/14 Paul Gortmaker <[email protected]>:
>> On Thu, Mar 14, 2013 at 4:39 PM, Andrew Morton
>> <[email protected]> wrote:
>>> On Thu, 14 Mar 2013 15:26:29 +0100 Frederic Weisbecker <[email protected]> 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.
--
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/