xnu-792.tar.gz

[apple/xnu.git] / pexpert / i386 / pe_kprintf.c

diff --git a/pexpert/i386/pe_kprintf.c b/pexpert/i386/pe_kprintf.c
index b82d5d43b6be5b91be69760c8eeef0903a50f70b..7e0ed56f116662b1890c9554e26d4a8cd3c03dc6 100644 (file)
--- a/pexpert/i386/pe_kprintf.c
+++ b/pexpert/i386/pe_kprintf.c
@@ -84,8 +84,17 @@ void kprintf(const char *fmt, ...)
     boolean_t state;
     
     if (!disableSerialOuput) {
-        state = ml_set_interrupts_enabled(FALSE);
-        simple_lock(&kprintf_lock);
+
+       /*
+        * Spin to get kprintf lock but re-enable interrupts while failing.
+        * This allows interrupts to be handled while waiting but
+        * interrupts are disabled once we have the lock.
+        */
+       state = ml_set_interrupts_enabled(FALSE);
+       while (!simple_lock_try(&kprintf_lock)) {
+             ml_set_interrupts_enabled(state);
+             ml_set_interrupts_enabled(FALSE);
+       }
 
        if (cpu_number() != cpu_last_locked) {
            MP_DEBUG_KPRINTF("[cpu%d...]\n", cpu_number());