From: Dave Jiang <dave.jiang@intel.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Naresh Kamboju <naresh.kamboju@linaro.org>,
linux-serial@vger.kernel.org,
open list <linux-kernel@vger.kernel.org>,
Vinod Koul <vkoul@kernel.org>, Jiri Slaby <jslaby@suse.com>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
linux-tegra <linux-tegra@vger.kernel.org>,
jirislaby@kernel.org,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andy Gross <agross@kernel.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
ldewangan@nvidia.com, Thierry Reding <thierry.reding@gmail.com>,
Jon Hunter <jonathanh@nvidia.com>, Qian Cai <cai@lca.pw>,
lkft-triage@lists.linaro.org
Subject: Re: [qemu] boot failed: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
Date: Mon, 6 Jul 2020 08:26:56 -0700 [thread overview]
Message-ID: <ea69a0f8-af48-45a3-7969-c38e0f785599@intel.com> (raw)
In-Reply-To: <CAK8P3a2LmUVj-yhwxXeCpqdxqJpp0m-q9q9SKQpfh3tFgMXPQA@mail.gmail.com>
On 7/6/2020 8:24 AM, Arnd Bergmann wrote:
> On Mon, Jul 6, 2020 at 5:01 PM Dave Jiang <dave.jiang@intel.com> wrote:
>> On 7/6/2020 5:53 AM, Arnd Bergmann wrote:
>>> On Mon, Jul 6, 2020 at 1:03 PM Naresh Kamboju <naresh.kamboju@linaro.org> wrote:
>>
>> Arnd,
>> I'm looking at the pl001_dma_probe(), I think we could make it more robust if it
>> uses IS_ERR_OR_NULL(chan) instead of IS_ERR(). Should I send a patch for it? I
>> suppose looking at the comment header for dma_request_chan() it does say return
>> chan ptr or error ptr. Sorry I missed that.
>
> No. IS_ERR_OR_NULL() is almost always a mistake. A function should either
> return NULL on error, or it should return an error code, but should not be
> able to return either.
Fair enough.
>
> Have you checked all the other 'return NULL' statements in your patch to
> ensure that they never return error pointers?
Yeah I looked over the rest of them. The ones that are returning NULL as far as
I can tell are expected to return NULL.
>
> Arnd
>
next prev parent reply other threads:[~2020-07-06 15:27 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-06 11:03 [qemu] boot failed: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 Naresh Kamboju
2020-07-06 12:53 ` Arnd Bergmann
2020-07-06 14:33 ` Dave Jiang
2020-07-06 15:10 ` Vinod Koul
2020-07-06 15:01 ` Dave Jiang
2020-07-06 15:24 ` Arnd Bergmann
2020-07-06 15:26 ` Dave Jiang [this message]
2020-07-06 17:36 ` Naresh Kamboju
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