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[109.81.1.107]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4922fa891acsm161753865e9.9.2026.06.17.05.39.54 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 17 Jun 2026 05:39:54 -0700 (PDT) Message-ID: <79ace94f-31d3-4a5e-9a47-3fad69304fe5@suse.com> Date: Wed, 17 Jun 2026 14:39:53 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] init/main: Expose built-in initcalls and blacklist status via debugfs To: Aaron Tomlin Cc: arnd@arndb.de, mcgrof@kernel.org, da.gomez@kernel.org, samitolvanen@google.com, neelx@suse.com, sean@ashe.io, chjohnst@mail.com, steve@abita.co, mproche@mail.com, nick.lane@mail.com, linux-arch@vger.kernel.org, linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260510061301.41341-1-atomlin@atomlin.com> Content-Language: en-US From: Petr Pavlu In-Reply-To: <20260510061301.41341-1-atomlin@atomlin.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 5/10/26 8:13 AM, Aaron Tomlin wrote: > At present, identifying the correct function name to supply to the > "initcall_blacklist=" kernel command-line parameter requires manual > inspection of the source code or kernel symbol tables. Furthermore, > administrators lack a reliable runtime mechanism to verify whether a > specified built-in module has been successfully blacklisted. My understanding is that initcall_blacklist is primarily a debugging facility. This is documented in Documentation/admin-guide/kernel-parameters.txt [1] and also outlined in the initial commit 7b0b73d76651 ("init/main.c: add initcall_blacklist kernel parameter") [2]. It is expected that to use it, one must inspect the kernel source code. If the goal is to allow specific built-in modules to be blacklisted, I wonder whether extending module_blacklist to also cover built-in modules might be a better option. Module names are more appropriate for administrators to use, while initcall names should remain internal to the kernel. Additionally, initcalls are typically "static" and therefore are not guaranteed to have unique names + using module names avoids a dependency on CONFIG_KALLSYMS=y. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/admin-guide/kernel-parameters.txt?h=v7.1#n2408 [2] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7b0b73d76651e5f88c88b76efa18d719f832bf6f -- Thanks, Petr