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[142.167.219.86]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6f4c093452fsm9500826d6.44.2025.04.24.06.37.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 24 Apr 2025 06:38:00 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1u7wm7-00000007UU5-2Apr; Thu, 24 Apr 2025 10:37:59 -0300 Date: Thu, 24 Apr 2025 10:37:59 -0300 From: Jason Gunthorpe To: Baolu Lu Cc: "Tian, Kevin" , Joerg Roedel , Will Deacon , Robin Murphy , "iommu@lists.linux.dev" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 3/3] iommu/vt-d: Simplify domain_attach_iommu() Message-ID: <20250424133759.GA1213339@ziepe.ca> References: <20250423031020.2189546-1-baolu.lu@linux.intel.com> <20250423031020.2189546-4-baolu.lu@linux.intel.com> <42e8c668-e72d-490a-8a5e-8e94af90fda4@linux.intel.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: <42e8c668-e72d-490a-8a5e-8e94af90fda4@linux.intel.com> On Thu, Apr 24, 2025 at 05:22:48PM +0800, Baolu Lu wrote: > > > -err_clear: > > > - ida_free(&iommu->domain_ida, info->did); > > > -err_unlock: > > > - kfree(info); > > > - return ret; > > > + return xa_err(xa_store(&domain->iommu_array, iommu->seq_id, > > > + no_free_ptr(info), GFP_KERNEL)); > > > } > > > > no_free_ptr() should be used before successful return. Here xa_store() > > could return error but at that point no auto free as no_free_ptr() already > > changes 'info' to NULL. then memory leak. > > Hmm, I've considered this. My thought was that xa_store() failure only > occurs due to the system running out of memory, and the Linux kernel > can't recover from it. In that case, the system is already broken; > hence, handling the failure case here doesn't make things better. That's not the kernel pattern, you are supposed to unwind correctly in those failures I think you should not use cleanup.h for something complicated like this.. Jason