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Subject[GIT PULL] core kernel fixes
Linus,

Please pull the latest core-fixes-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git core-fixes-for-linus

This fixes the percpu related boot crash that i've reported.

Thanks,

Ingo

------------------>
Tejun Heo (2):
lockdep: Move early boot local IRQ enable/disable status to init/main.c
smp: Allow on_each_cpu() to be called while early_boot_irqs_disabled status to init/main.c


arch/x86/xen/enlighten.c | 2 +-
include/linux/kernel.h | 2 ++
include/linux/lockdep.h | 8 --------
init/main.c | 13 +++++++++++--
kernel/lockdep.c | 18 +-----------------
kernel/smp.c | 11 +++++++----
kernel/trace/trace_irqsoff.c | 8 --------
7 files changed, 22 insertions(+), 40 deletions(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 7e8d3bc..50542ef 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1194,7 +1194,7 @@ asmlinkage void __init xen_start_kernel(void)
per_cpu(xen_vcpu, 0) = &HYPERVISOR_shared_info->vcpu_info[0];

local_irq_disable();
- early_boot_irqs_off();
+ early_boot_irqs_disabled = true;

memblock_init();

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 5a9d905..d07d805 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -243,6 +243,8 @@ extern int test_taint(unsigned flag);
extern unsigned long get_taint(void);
extern int root_mountflags;

+extern bool early_boot_irqs_disabled;
+
/* Values used for system_state */
extern enum system_states {
SYSTEM_BOOTING,
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 71c09b2..f638fd7 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -436,16 +436,8 @@ do { \
#endif /* CONFIG_LOCKDEP */

#ifdef CONFIG_TRACE_IRQFLAGS
-extern void early_boot_irqs_off(void);
-extern void early_boot_irqs_on(void);
extern void print_irqtrace_events(struct task_struct *curr);
#else
-static inline void early_boot_irqs_off(void)
-{
-}
-static inline void early_boot_irqs_on(void)
-{
-}
static inline void print_irqtrace_events(struct task_struct *curr)
{
}
diff --git a/init/main.c b/init/main.c
index 00799c1..33c37c3 100644
--- a/init/main.c
+++ b/init/main.c
@@ -96,6 +96,15 @@ static inline void mark_rodata_ro(void) { }
extern void tc_init(void);
#endif

+/*
+ * Debug helper: via this flag we know that we are in 'early bootup code'
+ * where only the boot processor is running with IRQ disabled. This means
+ * two things - IRQ must not be enabled before the flag is cleared and some
+ * operations which are not allowed with IRQ disabled are allowed while the
+ * flag is set.
+ */
+bool early_boot_irqs_disabled __read_mostly;
+
enum system_states system_state __read_mostly;
EXPORT_SYMBOL(system_state);

@@ -554,7 +563,7 @@ asmlinkage void __init start_kernel(void)
cgroup_init_early();

local_irq_disable();
- early_boot_irqs_off();
+ early_boot_irqs_disabled = true;

/*
* Interrupts are still disabled. Do necessary setups, then
@@ -621,7 +630,7 @@ asmlinkage void __init start_kernel(void)
if (!irqs_disabled())
printk(KERN_CRIT "start_kernel(): bug: interrupts were "
"enabled early\n");
- early_boot_irqs_on();
+ early_boot_irqs_disabled = false;
local_irq_enable();

/* Interrupts are enabled now so all GFP allocations are safe. */
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 42ba65d..0d2058d 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -2292,22 +2292,6 @@ mark_held_locks(struct task_struct *curr, enum mark_type mark)
}

/*
- * Debugging helper: via this flag we know that we are in
- * 'early bootup code', and will warn about any invalid irqs-on event:
- */
-static int early_boot_irqs_enabled;
-
-void early_boot_irqs_off(void)
-{
- early_boot_irqs_enabled = 0;
-}
-
-void early_boot_irqs_on(void)
-{
- early_boot_irqs_enabled = 1;
-}
-
-/*
* Hardirqs will be enabled:
*/
void trace_hardirqs_on_caller(unsigned long ip)
@@ -2319,7 +2303,7 @@ void trace_hardirqs_on_caller(unsigned long ip)
if (unlikely(!debug_locks || current->lockdep_recursion))
return;

- if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled)))
+ if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled)))
return;

if (unlikely(curr->hardirqs_enabled)) {
diff --git a/kernel/smp.c b/kernel/smp.c
index 4ec30e0..4b83cd6 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -430,7 +430,7 @@ void smp_call_function_many(const struct cpumask *mask,
* can't happen.
*/
WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()
- && !oops_in_progress);
+ && !oops_in_progress && !early_boot_irqs_disabled);

/* So, what's a CPU they want? Ignoring this one. */
cpu = cpumask_first_and(mask, cpu_online_mask);
@@ -533,17 +533,20 @@ void ipi_call_unlock_irq(void)
#endif /* USE_GENERIC_SMP_HELPERS */

/*
- * Call a function on all processors
+ * Call a function on all processors. May be used during early boot while
+ * early_boot_irqs_disabled is set. Use local_irq_save/restore() instead
+ * of local_irq_disable/enable().
*/
int on_each_cpu(void (*func) (void *info), void *info, int wait)
{
+ unsigned long flags;
int ret = 0;

preempt_disable();
ret = smp_call_function(func, info, wait);
- local_irq_disable();
+ local_irq_save(flags);
func(info);
- local_irq_enable();
+ local_irq_restore(flags);
preempt_enable();
return ret;
}
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 5cf8c60..92b6e1e 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -453,14 +453,6 @@ void time_hardirqs_off(unsigned long a0, unsigned long a1)
* Stubs:
*/

-void early_boot_irqs_off(void)
-{
-}
-
-void early_boot_irqs_on(void)
-{
-}
-
void trace_softirqs_on(unsigned long ip)
{
}

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