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[142.167.219.86]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-47ae9cf9f7dsm69980821cf.74.2025.04.23.09.58.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Apr 2025 09:58:06 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1u7dQD-00000007LGX-1t9j; Wed, 23 Apr 2025 13:58:05 -0300 Date: Wed, 23 Apr 2025 13:58:05 -0300 From: Jason Gunthorpe To: Bjorn Helgaas Cc: Will McVicker , Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , "Rob Herring (Arm)" , Lorenzo Pieralisi , Robin Murphy , Joerg Roedel , Bjorn Helgaas , iommu@lists.linux.dev, Saravana Kannan , kernel-team@android.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v1] platform: Fix race condition during DMA configure at IOMMU probe time Message-ID: <20250423165805.GH1213339@ziepe.ca> References: <20250422232650.2737369-1-willmcvicker@google.com> <20250423150823.GA422889@bhelgaas> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250423150823.GA422889@bhelgaas> On Wed, Apr 23, 2025 at 10:08:23AM -0500, Bjorn Helgaas wrote: > I think this would all be clearer if we tested for the NULL pointer > explicitly before applying to_platform_driver(). I don't like setting > a pointer to an invalid value. I think it's better if the pointer is > either valid or uninitialized because the compiler can help find uses > of uninitialized pointers. +1 Jason