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AJvYcCUuR94uidKJnOAkEKwnxGUOKKzEKg1J1vZVA2MvCw6huzasJ9/4HNXhRRNmkWJ7qFieIQ0pUBOmYaSpKbvxOTg0N8yWqGzcaoKI2HEq3PslhOFabw8vkcIkc3GaVPQjls3mjr6KzWbOZ2bAWp/i4UUZ1JjrOucQFKj05HJs4kd9pg6sDTV3dHj4B7nFdx1zcg== X-Gm-Message-State: AOJu0YwPTZIriMOXJvJko+H53df7hpo+KpJOLmZuNem7cHBYf5+V4W35 m+KUEIWbPpFchawx8g6O6H7v6MMfZXt9ImNEnEYI0mDA/IISoo5k X-Google-Smtp-Source: AGHT+IEccN/3In/A/yvzAAHYBgExNt8p0GrOittDB7WrlvTOeGG15AWAaMHJHYacbPLd1/KvRB/yCQ== X-Received: by 2002:a17:902:d2cc:b0:1fd:6a00:582e with SMTP id d9443c01a7336-200952641bemr6352305ad.30.1723083070709; Wed, 07 Aug 2024 19:11:10 -0700 (PDT) Received: from smtpclient.apple ([47.89.225.180]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-1ff59295294sm113086435ad.253.2024.08.07.19.11.04 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 07 Aug 2024 19:11:10 -0700 (PDT) Content-Type: text/plain; charset=us-ascii Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3774.500.171.1.1\)) Subject: Re: [PATCH v2 3/3] tracing/kprobes: Use APIs that matches symbols without .XXX suffix From: zhang warden In-Reply-To: <22D3CE6E-945B-43C4-A3A2-C57588B12BD0@fb.com> Date: Thu, 8 Aug 2024 10:10:52 +0800 Cc: Steven Rostedt , Song Liu , "live-patching@vger.kernel.org" , LKML , "linux-trace-kernel@vger.kernel.org" , Josh Poimboeuf , Jiri Kosina , Miroslav Benes , Petr Mladek , Joe Lawrence , Nathan Chancellor , "morbo@google.com" , Justin Stitt , Luis Chamberlain , Leizhen , "kees@kernel.org" , Kernel Team , Matthew Maurer , Sami Tolvanen , Masami Hiramatsu Content-Transfer-Encoding: quoted-printable Message-Id: <5271E070-362B-403D-A7EE-FB0855F31DB2@gmail.com> References: <20240802210836.2210140-1-song@kernel.org> <20240802210836.2210140-4-song@kernel.org> <20240806144426.00ed349f@gandalf.local.home> <20240806160049.617500de@gandalf.local.home> <20240806160149.48606a0b@gandalf.local.home> <6F6AC75C-89F9-45C3-98FF-07AD73C38078@fb.com> <87F7024C-9049-4573-829B-79261FC87984@gmail.com> <22D3CE6E-945B-43C4-A3A2-C57588B12BD0@fb.com> To: Song Liu X-Mailer: Apple Mail (2.3774.500.171.1.1) > IIUC, constprop means const propagation. For example, function=20 > "foo(int a, int b)" that is called as "foo(a, 10)" will be come=20 > "foo(int a)" with a hard-coded b =3D 10 inside.=20 >=20 > .part.0 is part of the function, as the other part is inlined in=20 > the caller.=20 >=20 > With binary-diff based toolchain (kpatch-build), I think these will be=20= > handled automatically. >=20 > Thanks, > Song Yep, Thanks for your explanation! I discuss here just for an interest. IMO, more people may use tools like 'kpatch-build' to build a livepatch = for it will be more easy. But I think such tools should also be = attention to such changes because when it trying to do section-level or = symbol-level operations. Otherwise it may cause problems :) > However, if we write the livepatch manually, we=20 > need to understand these behavior with .constprop and .part.=20 Do you think it is wise to write a livepatch module manually? If we are = trying to write a module manually, we should also take care of the klp_* = function calling, while using a livepatch building tools will help = handle it :) Thanks. Wardenjohn=20