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[Qemu-devel] [5620] Add safety net against potential infinite loop
From: |
malc |
Subject: |
[Qemu-devel] [5620] Add safety net against potential infinite loop |
Date: |
Tue, 04 Nov 2008 14:18:15 +0000 |
Revision: 5620
http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=5620
Author: malc
Date: 2008-11-04 14:18:13 +0000 (Tue, 04 Nov 2008)
Log Message:
-----------
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.
Modified Paths:
--------------
trunk/cpu-exec.c
Modified: trunk/cpu-exec.c
===================================================================
--- trunk/cpu-exec.c 2008-11-04 13:17:17 UTC (rev 5619)
+++ trunk/cpu-exec.c 2008-11-04 14:18:13 UTC (rev 5620)
@@ -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 */
- [Qemu-devel] [5620] Add safety net against potential infinite loop,
malc <=