On 11 March 2014 23:58, Andreas Färber <afaer...@suse.de> wrote: > Am 20.02.2014 16:58, schrieb Peter Maydell: >> On 16 February 2014 02:07, Edgar E. Iglesias <edgar.igles...@gmail.com> >> wrote: >>> On Sat, Feb 15, 2014 at 03:42:56PM +0000, Peter Maydell wrote: >>>> On 13 February 2014 05:07, <edgar.igles...@gmail.com> wrote: >>>>> From: "Edgar E. Iglesias" <edgar.igles...@xilinx.com> >>>>> >>>>> cpu->exit_request is part of the execution environment and should >>>>> not be cleared when a CPU resets. >>>>> >>>>> Otherwise, we might deadlock QEMU if a CPU resets while there is >>>>> I/O going on. >>>>> >>>>> Signed-off-by: Edgar E. Iglesias <edgar.igles...@xilinx.com> >>>>> --- >>>>> qom/cpu.c | 1 - >>>>> 1 file changed, 1 deletion(-) >>>>> >>>>> diff --git a/qom/cpu.c b/qom/cpu.c >>>>> index 9d62479..40d82dd 100644 >>>>> --- a/qom/cpu.c >>>>> +++ b/qom/cpu.c >>>>> @@ -195,7 +195,6 @@ static void cpu_common_reset(CPUState *cpu) >>>>> log_cpu_state(cpu, cc->reset_dump_flags); >>>>> } >>>>> >>>>> - cpu->exit_request = 0; >>>>> cpu->interrupt_request = 0; >>>>> cpu->current_tb = NULL; >>>>> cpu->halted = 0; >>>> >>>> This looks kind of odd to me. What's the situation you see where >>>> this matters -- is the CPU resetting itself, or is some other device >>>> in another thread triggering the CPU reset? TCG or KVM? >>> >>> Seeing this in TCG. The CPU gets signaled by the IO thread while the >>> CPU is resetting itself. If the CPU looses the race, it clears its >>> exit_request leaving the IO thread waiting for the global lock >>> potentially forever. >>> >>> The CPU actually exits generated code but goes right back in because >>> there is no exit_request pending. >> >> Yes, having looked at the code I agree with you, so: >> >> Reviewed-by: Peter Maydell <peter.mayd...@linaro.org> > > Thanks, applied to qom-cpu (with clarified commit message): > https://github.com/afaerber/qemu-cpu/commits/qom-cpu
I'd forgotten about this, but it's a bugfix for a hang, right? Seems to me like we ought to put it into 2.0 -- were you planning to submit it via qom-cpu for 2.0? thanks -- PMM
