linux-kernel - Re: [PATCH v2] drm/amdgpu: fix multiple memory leaks

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Date:   Mon, 30 Sep 2019 16:31:51 -0500
From:   Navid Emamdoost <navid.emamdoost@...il.com>
To:     "Koenig, Christian" <Christian.Koenig@....com>
Cc:     "emamd001@....edu" <emamd001@....edu>,
        "smccaman@....edu" <smccaman@....edu>,
        "kjlu@....edu" <kjlu@....edu>,
        "Deucher, Alexander" <Alexander.Deucher@....com>,
        "Zhou, David(ChunMing)" <David1.Zhou@....com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>, Rex Zhu <Rex.Zhu@....com>,
        Sam Ravnborg <sam@...nborg.org>,
        "amd-gfx@...ts.freedesktop.org" <amd-gfx@...ts.freedesktop.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] drm/amdgpu: fix multiple memory leaks

On Thu, Sep 19, 2019 at 3:03 AM Koenig, Christian
<Christian.Koenig@....com> wrote:
>
> Am 18.09.19 um 21:05 schrieb Navid Emamdoost:
> > In acp_hw_init there are some allocations that needs to be released in
> > case of failure:
> >
> > 1- adev->acp.acp_genpd should be released if any allocation attemp for
> > adev->acp.acp_cell, adev->acp.acp_res or i2s_pdata fails.
> > 2- all of those allocations should be released if pm_genpd_add_device
> > fails.
> >
> > v2: moved the released into goto error handlings
> >
> > Signed-off-by: Navid Emamdoost <navid.emamdoost@...il.com>
> > ---
> >   drivers/gpu/drm/amd/amdgpu/amdgpu_acp.c | 30 +++++++++++++++++--------
> >   1 file changed, 21 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_acp.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_acp.c
> > index eba42c752bca..c0db75b71859 100644
> > --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_acp.c
> > +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_acp.c
> > @@ -184,7 +184,7 @@ static struct device *get_mfd_cell_dev(const char *device_name, int r)
> >    */
> >   static int acp_hw_init(void *handle)
> >   {
> > -     int r, i;
> > +     int r, i, ret;
> >       uint64_t acp_base;
> >       u32 val = 0;
> >       u32 count = 0;
> > @@ -231,20 +231,21 @@ static int acp_hw_init(void *handle)
> >       adev->acp.acp_cell = kcalloc(ACP_DEVS, sizeof(struct mfd_cell),
> >                                                       GFP_KERNEL);
> >
> > -     if (adev->acp.acp_cell == NULL)
> > -             return -ENOMEM;
> > +     if (adev->acp.acp_cell == NULL) {
> > +             ret = -ENOMEM;
> > +             goto out1;
> > +     }
> >
> >       adev->acp.acp_res = kcalloc(5, sizeof(struct resource), GFP_KERNEL);
> >       if (adev->acp.acp_res == NULL) {
> > -             kfree(adev->acp.acp_cell);
> > -             return -ENOMEM;
> > +             ret = -ENOMEM;
> > +             goto out2;
> >       }
> >
> >       i2s_pdata = kcalloc(3, sizeof(struct i2s_platform_data), GFP_KERNEL);
> >       if (i2s_pdata == NULL) {
> > -             kfree(adev->acp.acp_res);
> > -             kfree(adev->acp.acp_cell);
> > -             return -ENOMEM;
> > +             ret = -ENOMEM;
> > +             goto out3;
> >       }
> >
> >       switch (adev->asic_type) {
> > @@ -348,7 +349,8 @@ static int acp_hw_init(void *handle)
> >               r = pm_genpd_add_device(&adev->acp.acp_genpd->gpd, dev);
> >               if (r) {
> >                       dev_err(dev, "Failed to add dev to genpd\n");
> > -                     return r;
> > +                     ret = r;
> > +                     goto out4;
> >               }
> >       }
> >
> > @@ -393,6 +395,16 @@ static int acp_hw_init(void *handle)
> >       val &= ~ACP_SOFT_RESET__SoftResetAud_MASK;
> >       cgs_write_register(adev->acp.cgs_device, mmACP_SOFT_RESET, val);
> >       return 0;
> > +
> > +out4:
> > +     kfree(i2s_pdata);
> > +out3:
> > +     kfree(adev->acp.acp_res);
> > +out2:
> > +     kfree(adev->acp.acp_cell);
> > +out1:
> > +     kfree(adev->acp.acp_genpd);
>
> kfree on a NULL pointer is harmless, so a single error label should be
> sufficient.
>
I fixed this by just using failure label.

> Christian.
>
> > +     return ret;
> >   }
> >
> >   /**
>

In addition to previous cases, I covered 3 more error handling cases
that seemed need to goto failure. One where mfd_add_hotplug_devices
fails and the other two cases where time out values expire.


-- 
Navid.