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| author | aurel32 <aurel32@c046a42c-6fe2-441c-8c8c-71466251a162> | 2009-03-06 21:48:00 +0000 |
|---|---|---|
| committer | aurel32 <aurel32@c046a42c-6fe2-441c-8c8c-71466251a162> | 2009-03-06 21:48:00 +0000 |
| commit | 07279da1686009c42bb4d03f74cc84c96764683e (patch) | |
| tree | 0c85067ab440ccba46d3282cbe15cf75c8d6640f /cpu-exec.c | |
| parent | cd1d6caac86fc82df5c8de4c6086397efe40efb3 (diff) | |
| download | qemu-07279da1686009c42bb4d03f74cc84c96764683e.tar.gz qemu-07279da1686009c42bb4d03f74cc84c96764683e.tar.bz2 qemu-07279da1686009c42bb4d03f74cc84c96764683e.zip | |
Fix race condition on access to env->interrupt_request
env->interrupt_request is accessed as the bit level from both main code
and signal handler, making a race condition possible even on CISC CPU.
This causes freeze of QEMU under high load when running the dyntick
clock.
The patch below move the bit corresponding to CPU_INTERRUPT_EXIT in a
separate variable, declared as volatile sig_atomic_t, so it should be
work even on RISC CPU.
We may want to move the cpu_interrupt(env, CPU_INTERRUPT_EXIT) case in
its own function and get rid of CPU_INTERRUPT_EXIT. That can be done
later, I wanted to keep the patch short for easier review.
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6728 c046a42c-6fe2-441c-8c8c-71466251a162
Diffstat (limited to 'cpu-exec.c')
| -rw-r--r-- | cpu-exec.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/cpu-exec.c b/cpu-exec.c index f7be38df50..7607e240b5 100644 --- a/cpu-exec.c +++ b/cpu-exec.c @@ -311,7 +311,7 @@ int cpu_exec(CPUState *env1) env->exception_index = -1; } #ifdef USE_KQEMU - if (kqemu_is_ok(env) && env->interrupt_request == 0) { + if (kqemu_is_ok(env) && env->interrupt_request == 0 && env->exit_request == 0) { int ret; env->eflags = env->eflags | helper_cc_compute_all(CC_OP) | (DF & DF_MASK); ret = kqemu_cpu_exec(env); @@ -326,7 +326,7 @@ int cpu_exec(CPUState *env1) } else if (ret == 2) { /* softmmu execution needed */ } else { - if (env->interrupt_request != 0) { + if (env->interrupt_request != 0 || env->exit_request != 0) { /* hardware interrupt will be executed just after */ } else { /* otherwise, we restart */ @@ -525,11 +525,11 @@ int cpu_exec(CPUState *env1) the program flow was changed */ next_tb = 0; } - if (interrupt_request & CPU_INTERRUPT_EXIT) { - env->interrupt_request &= ~CPU_INTERRUPT_EXIT; - env->exception_index = EXCP_INTERRUPT; - cpu_loop_exit(); - } + } + if (unlikely(env->exit_request)) { + env->exit_request = 0; + env->exception_index = EXCP_INTERRUPT; + cpu_loop_exit(); } #ifdef DEBUG_EXEC if (qemu_loglevel_mask(CPU_LOG_TB_CPU)) { @@ -599,7 +599,7 @@ 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->interrupt_request & CPU_INTERRUPT_EXIT)) + if (unlikely (env->exit_request)) env->current_tb = NULL; while (env->current_tb) { |