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Fri, 12 Jun 2026 07:53:52 -0700 (PDT) MIME-Version: 1.0 References: <0f97352506d8d813f70f441de4d63fcd5b7d1c3e.1779123847.git.shuvampandey1@gmail.com> <20260611221000.GA524832@bhelgaas> In-Reply-To: <20260611221000.GA524832@bhelgaas> From: Shuvam Pandey Date: Fri, 12 Jun 2026 20:38:41 +0545 X-Gm-Features: AVVi8CeSnuFKBXw07pnZfggT3zcPEONqkcJp-rRWL-FHYqitFjSsHZlw-QFmmE4 Message-ID: Subject: Re: [PATCH 1/2] PCI: dwc: Guard RAS DES debugfs deinit To: Bjorn Helgaas Cc: Jingoo Han , Manivannan Sadhasivam , Lorenzo Pieralisi , =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= , Bjorn Helgaas , Yue Wang , Neil Armstrong , Rob Herring , Kevin Hilman , Jerome Brunet , Martin Blumenstingl , Fan Ni , Shradha Todi , Hanjie Lin , linux-pci@vger.kernel.org, linux-amlogic@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260612_075354_103728_DF8215EE X-CRM114-Status: UNSURE ( 7.15 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-amlogic@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-amlogic" Errors-To: linux-amlogic-bounces+linux-amlogic=archiver.kernel.org@lists.infradead.org Hi Bjorn, > I guess this prevents a NULL pointer dereference, right? Yes. This is in the CONFIG_PCIE_DW_DEBUGFS teardown path when the controller does not advertise the RAS DES capability. In that case dwc_pcie_rasdes_debugfs_init() returns 0 before allocating pci->debugfs->rasdes_info or initializing reg_event_lock. Later, dwc_pcie_debugfs_deinit() still calls dwc_pcie_rasdes_debugfs_deinit() unconditionally. With CONFIG_DEBUG_MUTEXES, mutex_destroy() dereferences the mutex, so calling it via &rinfo->reg_event_lock when rinfo is NULL would dereference NULL. Without CONFIG_DEBUG_MUTEXES, mutex_destroy() is a no-op, but there is still no RAS DES state to tear down. So the patch makes the deinit path match the init path: if no rasdes_info was allocated, skip the RAS DES mutex teardown. Thanks, Shuvam _______________________________________________ linux-amlogic mailing list linux-amlogic@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-amlogic