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[2003:e5:8729:4000:29eb:6d9d:3214:39d2]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-579d7276d95sm3726512a12.78.2024.05.29.06.28.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 29 May 2024 06:28:45 -0700 (PDT) Message-ID: <2095a4a2-7db5-4de6-9609-d8e6a5adf27f@suse.com> Date: Wed, 29 May 2024 15:28:44 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] xen/xenbus: handle pointer to NULL in alloc/free_pdev To: yskelg@gmail.com, Stefano Stabellini , Oleksandr Tyshchenko Cc: skhan@linuxfoundation.org, sj@kernel.org, Austin Kim , shjy180909@gmail.com, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, linux-kernel-mentees@lists.linuxfoundation.org References: <20240529131926.29590-1-yskelg@gmail.com> Content-Language: en-US From: =?UTF-8?B?SsO8cmdlbiBHcm/Dnw==?= In-Reply-To: <20240529131926.29590-1-yskelg@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 29.05.24 15:19, yskelg@gmail.com wrote: > From: Yunseong Kim > > Modify 'alloc_pdev()' to set 'pdev->xdev' to NULL > if 'xen_pcibk_init_devices()' fails. This ensures that 'pdev->xdev' does > not point to 'xdev' when 'pdev' is freed. > And modify 'free_pdev()' to set 'pdev' to NULL. > > Signed-off-by: Yunseong Kim > --- > drivers/xen/xen-pciback/xenbus.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/xen/xen-pciback/xenbus.c b/drivers/xen/xen-pciback/xenbus.c > index b11e401f1b1e..f1709b8e284a 100644 > --- a/drivers/xen/xen-pciback/xenbus.c > +++ b/drivers/xen/xen-pciback/xenbus.c > @@ -54,6 +54,7 @@ static struct xen_pcibk_device *alloc_pdev(struct xenbus_device *xdev) > INIT_WORK(&pdev->op_work, xen_pcibk_do_op); > > if (xen_pcibk_init_devices(pdev)) { > + pdev->xdev = NULL; > kfree(pdev); > pdev = NULL; > } > @@ -102,6 +103,7 @@ static void free_pdev(struct xen_pcibk_device *pdev) > pdev->xdev = NULL; > > kfree(pdev); > + pdev = NULL; > } > > static int xen_pcibk_do_attach(struct xen_pcibk_device *pdev, int gnt_ref, NAK! Please stop that nonsense. NULL-ing pointers which have no chance to be used any more is just adding code for no purpose at all. Please don't send other iterations of this patch. You are wasting review bandwidth. Juergen