Re: [PATCH v1] drm/amdkfd: Check for potential null return of kmalloc_array()

From: Alex Deucher <alexdeucher@gmail.com>
To: QintaoShen <unSimple1993@163.com>
Cc: "Kuehling, Felix" <Felix.Kuehling@amd.com>,
	LKML <linux-kernel@vger.kernel.org>,
	amd-gfx list <amd-gfx@lists.freedesktop.org>
Subject: Re: [PATCH v1] drm/amdkfd: Check for potential null return of kmalloc_array()
Date: Thu, 24 Mar 2022 15:51:09 -0400	[thread overview]
Message-ID: <CADnq5_PkpohP3zYxMMoS7i_nRxTZfg0d3tiwPQA2hK3RFHVjMw@mail.gmail.com> (raw)
In-Reply-To: <1648110383-3533-1-git-send-email-unSimple1993@163.com>

Applied.  Thanks!

Alex

On Thu, Mar 24, 2022 at 9:46 AM QintaoShen <unSimple1993@163.com> wrote:
>
> As the kmalloc_array() may return null, the 'event_waiters[i].wait' would lead to null-pointer dereference.
> Therefore, it is better to check the return value of kmalloc_array() to avoid this confusion.
>
> Signed-off-by: QintaoShen <unSimple1993@163.com>
> ---
>  drivers/gpu/drm/amd/amdkfd/kfd_events.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_events.c b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
> index deeccce..64f4a51 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_events.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
> @@ -749,6 +749,8 @@ static struct kfd_event_waiter *alloc_event_waiters(uint32_t num_events)
>         event_waiters = kmalloc_array(num_events,
>                                         sizeof(struct kfd_event_waiter),
>                                         GFP_KERNEL);
> +       if (!event_waiters)
> +               return NULL;
>
>         for (i = 0; (event_waiters) && (i < num_events) ; i++) {
>                 init_wait(&event_waiters[i].wait);
> --
> 2.7.4
>