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Wed, 15 Jul 2026 12:37:33 -0700 (PDT) Received: from ziepe.ca ([159.2.72.92]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-51caab6e9f4sm144211471cf.2.2026.07.15.12.37.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Jul 2026 12:37:32 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1wk5QC-00000000tnI-0nFm; Wed, 15 Jul 2026 16:37:32 -0300 Date: Wed, 15 Jul 2026 16:37:32 -0300 From: Jason Gunthorpe To: weimin xiong Cc: Will Deacon , Robin Murphy , Joerg Roedel , Benjamin Gaignard , Rob Clark , linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org Subject: Re: [PATCH v1 2/4] iommu/arm-smmu-v3: Fix fwnode lookup lifetime handling Message-ID: <20260715193732.GA210048@ziepe.ca> References: <20260714060930.220277-1-xiongwm2026@163.com> <20260714060930.220277-3-xiongwm2026@163.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260714060930.220277-3-xiongwm2026@163.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260715_123735_472771_E9ACE23D X-CRM114-Status: GOOD ( 12.29 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jul 14, 2026 at 02:09:28PM +0800, weimin xiong wrote: > bus_find_device_by_fwnode() returns a device with its reference count > incremented. arm_smmu_get_by_fwnode() drops that reference before > reading the driver data, which leaves the returned pointer derived from > a device after its reference has been released. > > Read the driver data before put_device() and return NULL directly when > the lookup fails. > > Signed-off-by: weimin xiong > --- > drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) Reviewed-by: Jason Gunthorpe Jason