[PATCH RT 0/2] [ANNOUNCE] 3.0.41-rt62-rc1 stable review

Dear RT Folks,

This is the RT stable review cycle of patch 3.0.41-rt62-rc1.

Please scream at me if I messed something up. Please test the patches too.

The -rc release will be uploaded to kernel.org and will be deleted when
the final release is out. This is just a review release (or release candidate).

The pre-releases will not be pushed to the git repository, only the
final release is.

If all goes well, this patch will be converted to the next main release
on 8/29/2012 (again on the late Michael Jackson's B-day, and my
buddy Derek's)

Enjoy,

-- Steve


To build 3.0.41-rt62-rc1 directly, the following patches should be applied:

  http://www.kernel.org/pub/linux/kernel/v3.0/linux-3.0.tar.xz

  http://www.kernel.org/pub/linux/kernel/v3.0/patch-3.0.41.xz

  http://www.kernel.org/pub/linux/kernel/projects/rt/3.0/patch-3.0.41-rt62-rc1.patch.xz

You can also build from 3.0.41-rt61 by applying the incremental patch:

http://www.kernel.org/pub/linux/kernel/projects/rt/3.0/incr/patch-3.0.41-rt61-rt62-rc1.patch.xz


Changes from 3.0.41-rt61:

---


Frank Rowand (1):
      fix printk flush of messages

Steven Rostedt (1):
      Linux 3.0.41-rt62-rc1

----
 kernel/printk.c |    2 +-
 localversion-rt |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

---
 localversion-rt |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/localversion-rt b/localversion-rt
index 9b7de93..fef6b3c 100644
--- a/localversion-rt
+++ b/localversion-rt

@@ -1 +1 @@
--rt61
+-rt62-rc1

-- 
1.7.10.4

Updates console-make-rt-friendly.patch

#ifdef CONFIG_PREEMPT_RT_FULL, printk() output is never flushed by
printk() because:

   # some liberties taken in this pseudo-code to make it easier to follow
   printk()
      vprintk()
         raw_spin_lock(&logbuf_lock)
            # increment preempt_count():
            preempt_disable()
      result = console_trylock_for_printk()
         retval = 0
         # lock will always be false, because preempt_count() will be >= 1
         lock = ... && !preempt_count()
         if (lock)
            retval = 1
         return retval
      # result will always be false since lock will always be false
      if (result)
         console_unlock()
            # this is where the printk() output would be flushed

On system boot some printk() output is flushed because register_console()
and tty_open() call console_unlock().

This change also fixes the problem that was previously fixed by
preempt-rt-allow-immediate-magic-sysrq-output-for-preempt_rt_full.patch

Signed-off-by: Frank Rowand <redacted>
Cc: Frank <redacted>
Link: http://lkml.kernel.org/r/4FB44FD0.4090800@am.sony.com
Signed-off-by: Thomas Gleixner <redacted>
---
 kernel/printk.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/printk.c b/kernel/printk.c
index 60f4290..f2c459f 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c

@@ -835,7 +835,7 @@ static int console_trylock_for_printk(unsigned int cpu, unsigned long flags)
 {
 #ifdef CONFIG_PREEMPT_RT_FULL
 	int lock = (!early_boot_irqs_disabled && !irqs_disabled_flags(flags) &&
-		!preempt_count()) || sysrq_in_progress;
+		(preempt_count() <= 1)) || sysrq_in_progress;
 #else
 	int lock = 1;
 #endif

-- 
1.7.10.4

Hi,

I have tested this patch on our board (custom i.MX31 ARMv6 based) and
everything seems to be working as expected.

Thanks,
Michael

--
Scanned by MailScanner.

On 08/24/12 20:49, Steven Rostedt wrote:

Dear RT Folks,

This is the RT stable review cycle of patch 3.0.41-rt62-rc1.

Please scream at me if I messed something up. Please test the patches too.

I should have looked harder when Michael requested my patch be applied to the
stable series.

My patch was part of a two patch series, sent 5/16.  The first patch was
a reversal of preempt-rt-allow-immediate-magic-sysrq-output-for-preempt_rt_full.patch

The second patch works fine without the first patch.  But the second patch (the one
in 3.0.41-rt62-rc1) removes the need for
preempt-rt-allow-immediate-magic-sysrq-output-for-preempt_rt_full.patch

It is not a big deal if the reversal patch gets left out of the stable releases,
but it is cleaner if it is included.

This also applies to 3.2.28-rt42-rc1

< snip >

Changes from 3.0.41-rt61:

---


Frank Rowand (1):
      fix printk flush of messages

Steven Rostedt (1):
      Linux 3.0.41-rt62-rc1

----
 kernel/printk.c |    2 +-
 localversion-rt |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

-Frank