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Add safety net against potential infinite loop

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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
This commit is contained in:
malc 2008-11-04 14:18:13 +00:00
parent 0c5f3c8d7d
commit 55e8b85e48
1 changed files with 8 additions and 0 deletions
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8
cpu-exec.c
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@ -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 */