Jan Kiszka wrote: > And there is some race that cause a lock up in qemu_mutex_lock_iothread > after a while (the cpu_unlink_tb seems to race with the linking - just a > guess so far).
This seems to fix a long-standing race between cpu_exec and
signal-driven cpu_unlink_tb:
diff --git a/cpu-exec.c b/cpu-exec.c
index 026980a..bfc34e4 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -599,8 +598,9 @@ int cpu_exec(CPUState *env1)
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->exit_request)) {
- env->current_tb = tb;
+ env->current_tb = tb;
+ asm("");
+ if (likely(!env->exit_request)) {
tc_ptr = tb->tc_ptr;
/* execute the generated code */
#if defined(__sparc__) && !defined(CONFIG_SOLARIS)
@@ -609,7 +609,6 @@ int cpu_exec(CPUState *env1)
#define env cpu_single_env
#endif
next_tb = tcg_qemu_tb_exec(tc_ptr);
- env->current_tb = NULL;
if ((next_tb & 3) == 2) {
/* Instruction counter expired. */
int insns_left;
@@ -638,6 +637,7 @@ int cpu_exec(CPUState *env1)
}
}
}
+ env->current_tb = NULL;
/* reset soft MMU for next block (it can currently
only be set by a memory fault) */
} /* for(;;) */
Still testing, though.
Jan
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