[PATCH RT 0/6] [ANNOUNCE] 3.4.29-rt42-rc1 stable review

[PATCH RT 0/6] [ANNOUNCE] 3.4.29-rt42-rc1 stable review

[Steven Rostedt]

Dear RT Folks,

This is the RT stable review cycle of patch 3.4.29-rt42-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 2/8/2013.

Enjoy,

-- Steve


To build 3.4.29-rt42-rc1 directly, the following patches should be applied:

  http://www.kernel.org/pub/linux/kernel/v3.x/linux-3.4.tar.xz

  http://www.kernel.org/pub/linux/kernel/v3.x/patch-3.4.29.xz

  http://www.kernel.org/pub/linux/kernel/projects/rt/3.4/patch-3.4.29-rt42-rc1.patch.xz

You can also build from 3.4.29-rt41 by applying the incremental patch:

http://www.kernel.org/pub/linux/kernel/projects/rt/3.4/incr/patch-3.4.29-rt41-rt42-rc1.patch.xz


Changes from 3.4.29-rt41:

---


Steven Rostedt (1):
      Linux 3.4.29-rt42-rc1

Thomas Gleixner (5):
      drivers-tty-pl011-irq-disable-madness.patch
      mmci: Remove bogus local_irq_save()
      sched: Init idle->on_rq in init_idle()
      sched: Check for idle task in might_sleep()
      mm: swap: Initialize local locks early

----
 drivers/mmc/host/mmci.c         |    5 -----
 drivers/tty/serial/amba-pl011.c |   15 ++++++++++-----
 kernel/sched/core.c             |    4 +++-
 localversion-rt                 |    2 +-
 mm/swap.c                       |   12 +++++++++---
 5 files changed, 23 insertions(+), 15 deletions(-)

[PATCH RT 1/6] drivers-tty-pl011-irq-disable-madness.patch

[Steven Rostedt]

[-- Attachment #1: 0001-drivers-tty-pl011-irq-disable-madness.patch.patch --]
[-- Type: text/plain, Size: 1480 bytes --]

From: Thomas Gleixner <tglx@linutronix.de>

Cc: stable-rt@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 drivers/tty/serial/amba-pl011.c |   15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index b69356c..7b29c92 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c
@@ -1788,13 +1788,19 @@ pl011_console_write(struct console *co, const char *s, unsigned int count)
 
 	clk_enable(uap->clk);
 
-	local_irq_save(flags);
+	/*
+	 * local_irq_save(flags);
+	 *
+	 * This local_irq_save() is nonsense. If we come in via sysrq
+	 * handling then interrupts are already disabled. Aside of
+	 * that the port.sysrq check is racy on SMP regardless.
+	*/
 	if (uap->port.sysrq)
 		locked = 0;
 	else if (oops_in_progress)
-		locked = spin_trylock(&uap->port.lock);
+		locked = spin_trylock_irqsave(&uap->port.lock, flags);
 	else
-		spin_lock(&uap->port.lock);
+		spin_lock_irqsave(&uap->port.lock, flags);
 
 	/*
 	 *	First save the CR then disable the interrupts
@@ -1816,8 +1822,7 @@ pl011_console_write(struct console *co, const char *s, unsigned int count)
 	writew(old_cr, uap->port.membase + UART011_CR);
 
 	if (locked)
-		spin_unlock(&uap->port.lock);
-	local_irq_restore(flags);
+		spin_unlock_irqrestore(&uap->port.lock, flags);
 
 	clk_disable(uap->clk);
 }
-- 
1.7.10.4

[PATCH RT 2/6] mmci: Remove bogus local_irq_save()

[-- Attachment #1: 0002-mmci-Remove-bogus-local_irq_save.patch --]
[-- Type: text/plain, Size: 1088 bytes --]

From: Thomas Gleixner <tglx@linutronix.de>

On !RT interrupt runs with interrupts disabled. On RT it's in a
thread, so no need to disable interrupts at all.

Cc: stable-rt@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 drivers/mmc/host/mmci.c |    5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 032b847..6f8a1a7 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -910,15 +910,12 @@ static irqreturn_t mmci_pio_irq(int irq, void *dev_id)
 	struct sg_mapping_iter *sg_miter = &host->sg_miter;
 	struct variant_data *variant = host->variant;
 	void __iomem *base = host->base;
-	unsigned long flags;
 	u32 status;
 
 	status = readl(base + MMCISTATUS);
 
 	dev_dbg(mmc_dev(host->mmc), "irq1 (pio) %08x\n", status);
 
-	local_irq_save(flags);
-
 	do {
 		unsigned int remain, len;
 		char *buffer;
@@ -958,8 +955,6 @@ static irqreturn_t mmci_pio_irq(int irq, void *dev_id)
 
 	sg_miter_stop(sg_miter);
 
-	local_irq_restore(flags);

[PATCH RT 2/6] mmci: Remove bogus local_irq_save()

[Steven Rostedt]

[-- Attachment #1: 0002-mmci-Remove-bogus-local_irq_save.patch --]
[-- Type: text/plain, Size: 1243 bytes --]

From: Thomas Gleixner <tglx@linutronix.de>

On !RT interrupt runs with interrupts disabled. On RT it's in a
thread, so no need to disable interrupts at all.

Cc: stable-rt@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 drivers/mmc/host/mmci.c |    5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index 032b847..6f8a1a7 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -910,15 +910,12 @@ static irqreturn_t mmci_pio_irq(int irq, void *dev_id)
 	struct sg_mapping_iter *sg_miter = &host->sg_miter;
 	struct variant_data *variant = host->variant;
 	void __iomem *base = host->base;
-	unsigned long flags;
 	u32 status;
 
 	status = readl(base + MMCISTATUS);
 
 	dev_dbg(mmc_dev(host->mmc), "irq1 (pio) %08x\n", status);
 
-	local_irq_save(flags);
-
 	do {
 		unsigned int remain, len;
 		char *buffer;
@@ -958,8 +955,6 @@ static irqreturn_t mmci_pio_irq(int irq, void *dev_id)
 
 	sg_miter_stop(sg_miter);
 
-	local_irq_restore(flags);
-
 	/*
 	 * If we have less than the fifo 'half-full' threshold to transfer,
 	 * trigger a PIO interrupt as soon as any data is available.
-- 
1.7.10.4

[PATCH RT 3/6] sched: Init idle->on_rq in init_idle()

[Steven Rostedt]

[-- Attachment #1: 0003-sched-Init-idle-on_rq-in-init_idle.patch --]
[-- Type: text/plain, Size: 604 bytes --]

From: Thomas Gleixner <tglx@linutronix.de>

Cc: stable-rt@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/sched/core.c |    1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index fec5603..e979551 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5264,6 +5264,7 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu)
 	rcu_read_unlock();
 
 	rq->curr = rq->idle = idle;
+	idle->on_rq = 1;
 #if defined(CONFIG_SMP)
 	idle->on_cpu = 1;
 #endif
-- 
1.7.10.4

[PATCH RT 4/6] sched: Check for idle task in might_sleep()

[Steven Rostedt]

[-- Attachment #1: 0004-sched-Check-for-idle-task-in-might_sleep.patch --]
[-- Type: text/plain, Size: 985 bytes --]

From: Thomas Gleixner <tglx@linutronix.de>

Idle is not allowed to call sleeping functions ever!

Cc: stable-rt@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 kernel/sched/core.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index e979551..751ec60 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7536,7 +7536,8 @@ void __might_sleep(const char *file, int line, int preempt_offset)
 	static unsigned long prev_jiffy;	/* ratelimiting */
 
 	rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
-	if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
+	if ((preempt_count_equals(preempt_offset) && !irqs_disabled() &&
+	     !is_idle_task(current)) ||
 	    system_state != SYSTEM_RUNNING || oops_in_progress)
 		return;
 	if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
-- 
1.7.10.4

[PATCH RT 5/6] mm: swap: Initialize local locks early

[Steven Rostedt]

[-- Attachment #1: 0005-mm-swap-Initialize-local-locks-early.patch --]
[-- Type: text/plain, Size: 1029 bytes --]

From: Thomas Gleixner <tglx@linutronix.de>

Cc: stable-rt@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 mm/swap.c |   12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/mm/swap.c b/mm/swap.c
index 2051da9..62dc70c 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -767,6 +767,15 @@ unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping,
 }
 EXPORT_SYMBOL(pagevec_lookup_tag);
 
+/* Early setup for the local locks */
+static int __init swap_init_locks(void)
+{
+	local_irq_lock_init(rotate_lock);
+	local_irq_lock_init(swap_lock);
+	return 1;
+}
+early_initcall(swap_init_locks);
+
 /*
  * Perform any setup for the swap system
  */
@@ -774,9 +783,6 @@ void __init swap_setup(void)
 {
 	unsigned long megs = totalram_pages >> (20 - PAGE_SHIFT);
 
-	local_irq_lock_init(rotate_lock);
-	local_irq_lock_init(swap_lock);
-
 #ifdef CONFIG_SWAP
 	bdi_init(swapper_space.backing_dev_info);
 #endif
-- 
1.7.10.4

[PATCH RT 6/6] Linux 3.4.29-rt42-rc1

[Steven Rostedt]

[-- Attachment #1: 0006-Linux-3.4.29-rt42-rc1.patch --]
[-- Type: text/plain, Size: 287 bytes --]

From: Steven Rostedt <srostedt@redhat.com>

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

diff --git a/localversion-rt b/localversion-rt
index 629e0b4..31c892a 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt41
+-rt42-rc1
-- 
1.7.10.4