Re: [PATCH v3 1/6] s390x: fix memleaks in cpu_finalize

From: Pan Nengyuan <pannengyuan@huawei.com>
To: Cornelia Huck <cohuck@redhat.com>
Cc: peter.maydell@linaro.org, zhang.zhanghailiang@huawei.com,
	David Hildenbrand <david@redhat.com>,
	qemu-devel@nongnu.org, qemu-s390x@nongnu.org,
	qemu-arm@nongnu.org, euler.robot@huawei.com,
	Richard Henderson <rth@twiddle.net>
Subject: Re: [PATCH v3 1/6] s390x: fix memleaks in cpu_finalize
Date: Thu, 27 Feb 2020 19:25:55 +0800	[thread overview]
Message-ID: <50512b17-856b-f509-adb6-46015e86e000@huawei.com> (raw)
In-Reply-To: <20200227120649.50e6ea68.cohuck@redhat.com>

On 2/27/2020 7:06 PM, Cornelia Huck wrote:
> On Thu, 27 Feb 2020 10:50:50 +0800
> Pan Nengyuan <pannengyuan@huawei.com> wrote:
> 
>> This patch fix memleaks when we call tests/qtest/cpu-plug-test on s390x. The leak stack is as follow:
>>
>> Direct leak of 48 byte(s) in 1 object(s) allocated from:
>>     #0 0x7fb43c7cd970 in __interceptor_calloc (/lib64/libasan.so.5+0xef970)
>>     #1 0x7fb43be2149d in g_malloc0 (/lib64/libglib-2.0.so.0+0x5249d)
>>     #2 0x558ba96da716 in timer_new_full /mnt/sdb/qemu-new/qemu/include/qemu/timer.h:530
>>     #3 0x558ba96da716 in timer_new /mnt/sdb/qemu-new/qemu/include/qemu/timer.h:551
>>     #4 0x558ba96da716 in timer_new_ns /mnt/sdb/qemu-new/qemu/include/qemu/timer.h:569
>>     #5 0x558ba96da716 in s390_cpu_initfn /mnt/sdb/qemu-new/qemu/target/s390x/cpu.c:285
>>     #6 0x558ba9c969ab in object_init_with_type /mnt/sdb/qemu-new/qemu/qom/object.c:372
>>     #7 0x558ba9c9eb5f in object_initialize_with_type /mnt/sdb/qemu-new/qemu/qom/object.c:516
>>     #8 0x558ba9c9f053 in object_new_with_type /mnt/sdb/qemu-new/qemu/qom/object.c:684
>>     #9 0x558ba967ede6 in s390x_new_cpu /mnt/sdb/qemu-new/qemu/hw/s390x/s390-virtio-ccw.c:64
>>     #10 0x558ba99764b3 in hmp_cpu_add /mnt/sdb/qemu-new/qemu/hw/core/machine-hmp-cmds.c:57
>>     #11 0x558ba9b1c27f in handle_hmp_command /mnt/sdb/qemu-new/qemu/monitor/hmp.c:1082
>>     #12 0x558ba96c1b02 in qmp_human_monitor_command /mnt/sdb/qemu-new/qemu/monitor/misc.c:142
>>
>> Reported-by: Euler Robot <euler.robot@huawei.com>
>> Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
>> ---
>> Cc: Richard Henderson <rth@twiddle.net>
>> Cc: David Hildenbrand <david@redhat.com>
>> Cc: Cornelia Huck <cohuck@redhat.com>
>> Cc: qemu-s390x@nongnu.org
>> ---
>> v2->v1:
>> - Similarly to other cleanups, move timer_new into realize(Suggested by Philippe Mathieu-DaudÃ©)
>> v3->v2:
>> - Also do the timer_free in unrealize, it seems more balance.
>> ---
>>  target/s390x/cpu.c | 22 ++++++++++++++++++----
>>  1 file changed, 18 insertions(+), 4 deletions(-)
>>
>> diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
>> index cf84d307c6..cc63c9db22 100644
>> --- a/target/s390x/cpu.c
>> +++ b/target/s390x/cpu.c
>> @@ -170,7 +170,12 @@ static void s390_cpu_realizefn(DeviceState *dev, Error **errp)
>>      S390CPUClass *scc = S390_CPU_GET_CLASS(dev);
>>  #if !defined(CONFIG_USER_ONLY)
>>      S390CPU *cpu = S390_CPU(dev);
>> +    cpu->env.tod_timer =
>> +        timer_new_ns(QEMU_CLOCK_VIRTUAL, s390x_tod_timer, cpu);
>> +    cpu->env.cpu_timer =
>> +        timer_new_ns(QEMU_CLOCK_VIRTUAL, s390x_cpu_timer, cpu);
>>  #endif
> 
> It does not seem you addressed the comments I had last time, namely
> - memory leak on error (we do not go through unrealize if the device
>   was never completely realized)
> - coding style (initialization in middle of declaration section)

I am sorry, I misread the peter's reply and miss the codeing style too.

Apologies for you. I will change it.

Thanks.

> 
>> +
>>      Error *err = NULL;
>>  
>>      /* the model has to be realized before qemu_init_vcpu() due to kvm */
> 
> .
> 