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Subject: Re: [PATCH] drm/amd/amdkfd: fix possible memory leak in
 svm_range_restore_pages
To:     Xiyu Yang <xiyuyang19@fudan.edu.cn>,
        Alex Deucher <alexander.deucher@amd.com>,
        =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>,
        "Pan, Xinhui" <Xinhui.Pan@amd.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>, amd-gfx@lists.freedesktop.org,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Cc:     yuanxzhang@fudan.edu.cn, Xin Xiong <xiongx18@fudan.edu.cn>,
        Xin Tan <tanxin.ctf@gmail.com>
References: <1631161659-76719-1-git-send-email-xiyuyang19@fudan.edu.cn>
From:   Felix Kuehling <felix.kuehling@amd.com>
Message-ID: <af3a4d90-b988-d764-2b8e-6f8b19601eaf@amd.com>
Date:   Thu, 9 Sep 2021 01:01:00 -0400
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Hi Xiyu Yang,

This bug was already fixed by this commit:
https://gitlab.freedesktop.org/agd5f/linux/-/commit/598a118db0d85a432f8cd541a6a5d31e31c56b6b

Regards,
 Felix


Am 2021-09-09 um 12:27 a.m. schrieb Xiyu Yang:
> The memory leak issue may take place in an error handling path. When
> p->xnack_enabled is NULL, the function simply returns with -EFAULT and
> forgets to decrement the reference count of a kfd_process object bumped
> by kfd_lookup_process_by_pasid, which may incur memory leaks.
>
> Fix it by jumping to label "out", in which kfd_unref_process() decreases
> the refcount.
>
> Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
> Signed-off-by: Xin Xiong <xiongx18@fudan.edu.cn>
> Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
> ---
>  drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> index e883731c3f8f..0f7f1e5621ea 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
> @@ -2426,7 +2426,8 @@ svm_range_restore_pages(struct amdgpu_device *adev, unsigned int pasid,
>  	}
>  	if (!p->xnack_enabled) {
>  		pr_debug("XNACK not enabled for pasid 0x%x\n", pasid);
> -		return -EFAULT;
> +		r = -EFAULT;
> +		goto out;
>  	}
>  	svms = &p->svms;
>