Add safety net against potential infinite loop
cpu_interrupt might be called while translating the TB, but before it
is linked into a potentially infinite loop and becomes env->current_tb.
Currently this can (and does) cause huge problems only when using
dyntick clock, with other (periodic) clocks host_alarm_handler will
eventually be executed resulting in a call to cpu_interrupt which will
reset the recursion of running TB and the damage is "only" latency.
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5620 c046a42c-6fe2-441c-8c8c-71466251a162
diff --git a/cpu-exec.c b/cpu-exec.c
index d31a67a..62886a4 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -623,6 +623,14 @@
}
spin_unlock(&tb_lock);
env->current_tb = tb;
+
+ /* cpu_interrupt might be called while translating the
+ TB, but before it is linked into a potentially
+ infinite loop and becomes env->current_tb. Avoid
+ starting execution if there is a pending interrupt. */
+ if (unlikely (env->interrupt_request & CPU_INTERRUPT_EXIT))
+ env->current_tb = NULL;
+
while (env->current_tb) {
tc_ptr = tb->tc_ptr;
/* execute the generated code */
