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authormalc <malc@c046a42c-6fe2-441c-8c8c-71466251a162>2008-11-04 14:18:13 +0000
committermalc <malc@c046a42c-6fe2-441c-8c8c-71466251a162>2008-11-04 14:18:13 +0000
commit55e8b85e4891dafd0d0222ad1ced78e3c5f24e1e (patch)
treea9f89f6536dff7bbc0c79539ee1c3d8e785dd11a /cpu-exec.c
parent0c5f3c8d7d77307d79c6f764ef62ce6ffb3bc9e8 (diff)
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
Diffstat (limited to 'cpu-exec.c')
-rw-r--r--cpu-exec.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/cpu-exec.c b/cpu-exec.c
index d31a67aa4d..62886a4f18 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -623,6 +623,14 @@ int cpu_exec(CPUState *env1)
}
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 */