Re: [PATCH 4/8] spapr_pci: Fix memory leak of vmstate_spapr_pci

From: David Gibson <david@gibson.dropbear.id.au>
To: g00517791 <gaojinhao@huawei.com>
Cc: "Michael S . Tsirkin" <mst@redhat.com>,
	"Jason Wang" <jasowang@redhat.com>,
	"Stefan Berger" <stefanb@linux.vnet.ibm.com>,
	qemu-devel@nongnu.org, "Greg Kurz" <groug@kaod.org>,
	"Juan Quintela" <quintela@redhat.com>,
	qemu-ppc@nongnu.org, wanghaibin.wang@huawei.com,
	"Marc-André Lureau" <marcandre.lureau@redhat.com>,
	zhukeqian1@huawei.com,
	"Dr . David Alan Gilbert" <dgilbert@redhat.com>
Subject: Re: [PATCH 4/8] spapr_pci: Fix memory leak of vmstate_spapr_pci
Date: Mon, 28 Dec 2020 17:58:24 +1100	[thread overview]
Message-ID: <20201228065824.GB6952@yekko.fritz.box> (raw)
In-Reply-To: <20201226103347.868-5-gaojinhao@huawei.com>

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On Sat, Dec 26, 2020 at 06:33:43PM +0800, g00517791 wrote:
> From: Jinhao Gao <gaojinhao@huawei.com>
> 
> When VM migrate VMState of spapr_pci, the field(msi_devs) of spapr_pci
> having a flag of VMS_ALLOC need to allocate memory. If the src doesn't free
> memory of msi_devs in SaveStateEntry of spapr_pci after QEMUFile save
> VMState of spapr_pci, it may result in memory leak of msi_devs. We add the
> post_save func to free memory, which prevents memory leak.
> 
> Signed-off-by: Jinhao Gao <gaojinhao@huawei.com>

Not really a memory leak, since it will get freed on the next
pre_save.  But, we might as well free it earlier if we can ,so

Acked-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  hw/ppc/spapr_pci.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> index 76d7c91e9c..1b2b940606 100644
> --- a/hw/ppc/spapr_pci.c
> +++ b/hw/ppc/spapr_pci.c
> @@ -2173,6 +2173,16 @@ static int spapr_pci_pre_save(void *opaque)
>      return 0;
>  }
>  
> +static int spapr_pci_post_save(void *opaque)
> +{
> +    SpaprPhbState *sphb = opaque;
> +
> +    g_free(sphb->msi_devs);
> +    sphb->msi_devs = NULL;
> +    sphb->msi_devs_num = 0;
> +    return 0;
> +}
> +
>  static int spapr_pci_post_load(void *opaque, int version_id)
>  {
>      SpaprPhbState *sphb = opaque;
> @@ -2205,6 +2215,7 @@ static const VMStateDescription vmstate_spapr_pci = {
>      .version_id = 2,
>      .minimum_version_id = 2,
>      .pre_save = spapr_pci_pre_save,
> +    .post_save = spapr_pci_post_save,
>      .post_load = spapr_pci_post_load,
>      .fields = (VMStateField[]) {
>          VMSTATE_UINT64_EQUAL(buid, SpaprPhbState, NULL),

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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