[ANNOUNCE] 4.1.5-rt5

From: Sebastian Andrzej Siewior
Date: Sun Aug 16 2015 - 09:56:58 EST


Dear RT folks!

I'm pleased to announce the v4.1.5-rt5 patch set.
Changes since v4.1.5-rt4:

- don't disable preemption in dump_stack(). We should not see a
backtrace on a production kernel but then it should not increase the
latency if trigger one.

Known issues:

- bcache is disabled.

- CPU hotplug works in general. Steven's test script however
deadlocks usually on the second invocation.

- Clark Williams reported an OOPS in netlink_release() which has not
been narrowed down yet.

- Nicholas Mc Guire reported high CPU usage by softirq on an idle system
which seems to freeze / halt the system.

The delta patch against 4.1.5-rt4 is appended below and can be found here:

https://www.kernel.org/pub/linux/kernel/projects/rt/4.1/incr/patch-4.1.5-rt4-rt5.patch.xz

You can get this release via the git tree at:

git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git v4.1.5-rt5

The RT patch against 4.1.5 can be found here:

https://www.kernel.org/pub/linux/kernel/projects/rt/4.1/patch-4.1.5-rt5.patch.xz

The split quilt queue is available at:

https://www.kernel.org/pub/linux/kernel/projects/rt/4.1/patches-4.1.5-rt5.tar.xz

Sebastian

diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index 464ffd69b92e..00db1aad1548 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -42,7 +42,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, unsigned long bp,
const struct stacktrace_ops *ops, void *data)
{
- const unsigned cpu = get_cpu();
+ const unsigned cpu = get_cpu_light();
int graph = 0;
u32 *prev_esp;

@@ -86,7 +86,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
break;
touch_nmi_watchdog();
}
- put_cpu();
+ put_cpu_light();
}
EXPORT_SYMBOL(dump_trace);

diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 5f1c6266eb30..c331e3fef465 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -152,7 +152,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
unsigned long *stack, unsigned long bp,
const struct stacktrace_ops *ops, void *data)
{
- const unsigned cpu = get_cpu();
+ const unsigned cpu = get_cpu_light();
struct thread_info *tinfo;
unsigned long *irq_stack = (unsigned long *)per_cpu(irq_stack_ptr, cpu);
unsigned long dummy;
@@ -241,7 +241,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
* This handles the process stack:
*/
bp = ops->walk_stack(tinfo, stack, bp, ops, data, NULL, &graph);
- put_cpu();
+ put_cpu_light();
}
EXPORT_SYMBOL(dump_trace);

@@ -255,7 +255,7 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
int cpu;
int i;

- preempt_disable();
+ migrate_disable();
cpu = smp_processor_id();

irq_stack_end = (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
@@ -291,7 +291,7 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
pr_cont(" %016lx", *stack++);
touch_nmi_watchdog();
}
- preempt_enable();
+ migrate_enable();

pr_cont("\n");
show_trace_log_lvl(task, regs, sp, bp, log_lvl);
diff --git a/lib/dump_stack.c b/lib/dump_stack.c
index 6745c6230db3..7ccbc6ff80ea 100644
--- a/lib/dump_stack.c
+++ b/lib/dump_stack.c
@@ -33,7 +33,7 @@ asmlinkage __visible void dump_stack(void)
* Permit this cpu to perform nested stack dumps while serialising
* against other CPUs
*/
- preempt_disable();
+ migrate_disable();

retry:
cpu = smp_processor_id();
@@ -52,7 +52,7 @@ asmlinkage __visible void dump_stack(void)
if (!was_locked)
atomic_set(&dump_lock, -1);

- preempt_enable();
+ migrate_enable();
}
#else
asmlinkage __visible void dump_stack(void)
diff --git a/localversion-rt b/localversion-rt
index ad3da1bcab7e..0efe7ba1930e 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt4
+-rt5
--
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