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[69.172.146.21]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-231d4ed2ac7sm82687045ad.225.2025.05.20.17.58.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 20 May 2025 17:58:30 -0700 (PDT) From: Tony Ambardar X-Google-Original-From: Tony Ambardar Date: Tue, 20 May 2025 17:58:27 -0700 To: Alan Maguire Cc: Andrii Nakryiko , martin.lau@linux.dev, ast@kernel.org, andrii@kernel.org, alexis.lothore@bootlin.com, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, mykolal@fb.com, bpf@vger.kernel.org, dwarves@vger.kernel.org Subject: Re: [RFC bpf-next 0/3] bpf: handle 0-sized structs properly Message-ID: References: <20250508132237.1817317-1-alan.maguire@oracle.com> <8faae89d-3515-480c-9abe-4d0e7514e41b@oracle.com> <9a41b21f-c0ae-4298-bf95-09d0cdc3f3ab@oracle.com> Precedence: bulk X-Mailing-List: dwarves@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: <9a41b21f-c0ae-4298-bf95-09d0cdc3f3ab@oracle.com> On Tue, May 20, 2025 at 09:59:27AM +0100, Alan Maguire wrote: [...] > > I discussed this with Jose, and the gcc behaviour with zero-sized > structs varies a bit between architectures. Given that complexity, my > inclination would be to class functions with 0-sized struct parameters > as having inconsistent representations. They can then be tackled by > adding location info on a per-site basis later as part of the > inline-related work. For now we would just not emit BTF for them, since > without that site-specific analysis we can't be sure from function > signature alone where parameters are stored. In practice this means > leaving one function out of kernel BTF. > > So long story short, I think it might make sense to withdraw this series > for now and see if we can tweak Tony's patch to class functions with > 0-sized parameters as inconsistent as the v1 version did, meaning they > don't get a BTF representation. Thanks! > > Alan > [...] Agreed that sounds reasonable, and I'd like to resolve the original problem on 32-bit, so will update my patch and resend. Thanks, Tony