The blackfin boot_lock is used by the secondary processor startup code.
The locking task is the idle thread, which has
idle->sched_class == &idle_sched_class.
idle_sched_class->enqueue_task == NULL, so if the idle task blocks on the
lock, the attempt to wake it when the lock becomes available will fail:
try_to_wake_up()
...
activate_task()
enqueue_task()
p->sched_class->enqueue_task(rq, p, flags)
Fix by converting boot_lock to a raw spin lock.
This has not been compile or boot tested. The fix was needed by arm, this
patch is for all other instances of "boot_lock" in other architectures.
Signed-off-by: Frank Rowand <frank.rowand@xxxxxxxxxxx>
---
arch/blackfin/mach-bf561/smp.c | 10 5 + 5 - 0 !
1 file changed, 5 insertions(+), 5 deletions(-)
Index: b/arch/blackfin/mach-bf561/smp.c
===================================================================
--- a/arch/blackfin/mach-bf561/smp.c
+++ b/arch/blackfin/mach-bf561/smp.c
@@ -13,7 +13,7 @@
#include <asm/dma.h>
#include <asm/time.h>
-static DEFINE_SPINLOCK(boot_lock);
+static DEFINE_RAW_SPINLOCK(boot_lock);
/*
* platform_init_cpus() - Tell the world about how many cores we
@@ -70,8 +70,8 @@ void __cpuinit platform_secondary_init(u
/* We are done with local CPU inits, unblock the boot CPU. */
set_cpu_online(cpu, true);
- spin_lock(&boot_lock);
- spin_unlock(&boot_lock);
+ raw_spin_lock(&boot_lock);
+ raw_spin_unlock(&boot_lock);
}
int __cpuinit platform_boot_secondary(unsigned int cpu, struct task_struct *idle)
@@ -80,7 +80,7 @@ int __cpuinit platform_boot_secondary(un
printk(KERN_INFO "Booting Core B.\n");
- spin_lock(&boot_lock);
+ raw_spin_lock(&boot_lock);
if ((bfin_read_SYSCR() & COREB_SRAM_INIT) == 0) {
/* CoreB already running, sending ipi to wakeup it */
@@ -101,7 +101,7 @@ int __cpuinit platform_boot_secondary(un
if (cpu_online(cpu)) {
/* release the lock and let coreb run */
- spin_unlock(&boot_lock);
+ raw_spin_unlock(&boot_lock);
return 0;
} else
panic("CPU%u: processor failed to boot\n", cpu);
--
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