Received-SPF: pass (google.com: domain of linux-kernel+bounces-149721-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:40f1:3f00::1 as permitted sender) client-ip=2604:1380:40f1:3f00::1;
Date: Thu, 18 Apr 2024 10:29:20 +0200
From: Niklas Cassel <cassel@kernel.org>
To: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= <kw@linux.com>,
	Kishon Vijay Abraham I <kishon@kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Lorenzo Pieralisi <lpieralisi@kernel.org>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	Dan Carpenter <dan.carpenter@linaro.org>
Subject: Re: [PATCH v2 1/2] PCI: endpoint: pci-epf-test: Make use of cached
 'epc_features' in pci_epf_test_core_init()
Message-ID: <ZiDZ4Hgem9dP7iXz@ryzen>
References: <20240418-pci-epf-test-fix-v2-0-eacd54831444@linaro.org>
 <20240418-pci-epf-test-fix-v2-1-eacd54831444@linaro.org>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20240418-pci-epf-test-fix-v2-1-eacd54831444@linaro.org>

On Thu, Apr 18, 2024 at 01:29:58PM +0530, Manivannan Sadhasivam wrote:
> Instead of getting the epc_features from pci_epc_get_features() API, use
> the cached pci_epf_test::epc_features value to avoid the NULL check. Since
> the NULL check is already performed in pci_epf_test_bind(), having one more
> check in pci_epf_test_core_init() is redundant and it is not possible to
> hit the NULL pointer dereference.
> 
> Also with commit a01e7214bef9 ("PCI: endpoint: Remove "core_init_notifier"
> flag"), 'epc_features' got dereferenced without the NULL check, leading to
> the following false positive smatch warning:
> 
> drivers/pci/endpoint/functions/pci-epf-test.c:784 pci_epf_test_core_init()
> error: we previously assumed 'epc_features' could be null (see line 747)
> 
> So let's remove the redundant NULL check and also use the epc_features::
> {msix_capable/msi_capable} flags directly to avoid local variables.
> 
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Closes: https://lore.kernel.org/linux-pci/024b5826-7180-4076-ae08-57d2584cca3f@moroto.mountain/
> Fixes: 5e50ee27d4a5 ("PCI: pci-epf-test: Add support to defer core initialization")
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> ---

Reviewed-by: Niklas Cassel <cassel@kernel.org>