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[142.68.128.5]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6cb3b62d520sm60526996d6.67.2024.10.02.06.57.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 02 Oct 2024 06:57:29 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.95) (envelope-from ) id 1svzr6-009XEc-HO; Wed, 02 Oct 2024 10:57:28 -0300 Date: Wed, 2 Oct 2024 10:57:28 -0300 From: Jason Gunthorpe To: Nicolin Chen Cc: Pranjal Shrivastava , Joerg Roedel , Will Deacon , Robin Murphy , Mostafa Saleh , iommu@lists.linux.dev, Daniel Mentz Subject: Re: [PATCH v3 1/2] iommu/arm-smmu-v3: Print better events records Message-ID: <20241002135728.GD1369530@ziepe.ca> References: <20240928005143.2378938-1-praan@google.com> <20240928005143.2378938-2-praan@google.com> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Sep 30, 2024 at 12:15:10PM -0700, Nicolin Chen wrote: > > +static void arm_smmu_get_evt_info(struct arm_smmu_device *smmu, u64 *evt, > > + struct arm_smmu_event *event) > > +{ > > + mutex_lock(&smmu->streams_mutex); > > + event->master = arm_smmu_find_master(smmu, event->sid); > > + mutex_unlock(&smmu->streams_mutex); > > + > > + if (event->master) > > + event->master_name = dev_name(event->master->dev); > > + else > > + event->master_name = "(unassigned sid)"; > > Likely safer for dev_name to be in the mutex too. The result of arm_smmu_find_master() should not leave the lock, and dev_name()'s result can't leave the lock either, at least not with out some refcounting on the struct device. Jason