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From:   Arnd Bergmann <arnd@arndb.de>
Date:   Mon, 12 Apr 2021 20:41:38 +0200
Message-ID: <CAK8P3a2pSRu0OKDNrNJSdviRgcv8Lw1mwZr5opv=UbtHLps2oQ@mail.gmail.com>
Subject: Re: [PATCH][next] habanalabs/gaudi: Fix uninitialized return code rc
 when read size is zero
To:     Colin King <colin.king@canonical.com>
Cc:     Oded Gabbay <ogabbay@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Ofir Bitton <obitton@habana.ai>,
        kernel-janitors@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Mon, Apr 12, 2021 at 6:11 PM Colin King <colin.king@canonical.com> wrote:
>
> From: Colin Ian King <colin.king@canonical.com>
>
> In the case where size is zero the while loop never assigns rc and the
> return value is uninitialized. Fix this by initializing rc to zero.
>
> Addresses-Coverity: ("Uninitialized scalar variable")
> Fixes: 639781dcab82 ("habanalabs/gaudi: add debugfs to DMA from the device")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
>  drivers/misc/habanalabs/gaudi/gaudi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/misc/habanalabs/gaudi/gaudi.c b/drivers/misc/habanalabs/gaudi/gaudi.c
> index 8730b691ec61..b751652f80a8 100644
> --- a/drivers/misc/habanalabs/gaudi/gaudi.c
> +++ b/drivers/misc/habanalabs/gaudi/gaudi.c
> @@ -6252,7 +6252,7 @@ static int gaudi_debugfs_read_dma(struct hl_device *hdev, u64 addr, u32 size,
>         dma_addr_t dma_addr;
>         void *kernel_addr;
>         bool is_eng_idle;
> -       int rc, dma_id;
> +       int rc = 0, dma_id;
>
>         kernel_addr = hdev->asic_funcs->asic_dma_alloc_coherent(
>                                                 hdev, SZ_2M,


In general, I don't like adding initializations during the declaration as that
tends to hide warnings for the cases where a later initialization is
missing. In this case it looks correct though.

Acked-by: Arnd Bergmann <arnd@arndb.de>