From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4FC542D73A7; Thu, 18 Dec 2025 21:00:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766091610; cv=none; b=bXib4gsjM1Rda78bbN+zjtJ0Y/l+kOV4jlEOu+/dqH9xuQvD5oWPS+37BQyMmphdgY4KzqEfWnvNAZd8TAbuhLh5aN6SoVpJ1tIltZ0Zi8m1BsH/WHlIOyP4xWF9CcdaDlmww8LEDMFlO90a6ZIdZmuGFkmh4qYt4U0RdxMZChk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766091610; c=relaxed/simple; bh=ocVyW7CGSJZnuRqGhBS2hiaA0KAEoYpXnxRGkIt+GEs=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=UFYvfNc/G4RjWjpCH5gMGVac2rMXVtGm4xJU8KTi2JfvagK/onk+LVCoL6uiiiUh2rVYJ3uLs/yUk6LqI1mrsF1I1bRY9OI8sXL77vzaWc8Hbc8OBd9qLNmzpCwi5mkUrjQQMtlfg23TBZHf1xw13fOglEYPniWhGyskgNmFQcM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EtcP7kCe; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="EtcP7kCe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B6493C4CEFB; Thu, 18 Dec 2025 21:00:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1766091608; bh=ocVyW7CGSJZnuRqGhBS2hiaA0KAEoYpXnxRGkIt+GEs=; h=From:Subject:Date:To:Cc:From; b=EtcP7kCegT4Px2JQrRa2PLTqCF3BmKjDxvBVGNp7QVyhw4EFSWG1FT2ixpun9NOP0 KOmurcJzjwj/aH5DllRyraorW+oF8Y0wSPJOzwS6Zcf50NDXlmgv+IE3AnZYO2n8P0 qNYAJrxZL0I+lNOaHX0klfR23sUSS84UHFKHgpg9RAhZTf5nnLPE5Dwr0X8rjsad1u 5pamQUgU4wkpKma3B2QkXUukQc1unRQnzLfnerEwt9RuEw1SGbXL9iA19wqG+bCiuc TKjvH5P27zQ/QWL7MQ3u85O2EBdqqULWYoQ1ggtWkRFBFTJb9Kc53Os5zATOqyWUng 4RiaU6wc7oetQ== From: Daniel Gomez Subject: [PATCH 0/2] module: add -EEXIST module_init() reservation docs Date: Thu, 18 Dec 2025 21:59:43 +0100 Message-Id: <20251218-dev-module-init-eexists-modules-docs-v1-0-361569aa782a@samsung.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-B4-Tracking: v=1; b=H4sIAD9rRGkC/02O22rDMBBEf8XscxdWkmXL/pWSB11WraC2W0lxD CH/HpEL9PHMwMy5QuGcuMDcXSHznkra1gbiowP/bdcvxhQagySphRQGA++4bOH805o1VWQ+Uqn llRUMmy8ogh+9G+00OAdt6jdzTMfj5vP05Mx/5/ZWnyE4Wxj9tiypzh3rSHaYjFM9h3EgksFrH 6My1NtBeENSKTta+G85dw9HEurtd7F5xcwV9RTJaDkZ0nreBZxutzt7oOyN+QAAAA== X-Change-ID: 20251218-dev-module-init-eexists-modules-docs-1dc7cb7a96bb To: Luis Chamberlain , Petr Pavlu , Daniel Gomez , Sami Tolvanen , Aaron Tomlin , Jonathan Corbet , Lucas De Marchi Cc: linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, Daniel Gomez X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; a=openpgp-sha256; l=1337; i=da.gomez@samsung.com; h=from:subject:message-id; bh=ocVyW7CGSJZnuRqGhBS2hiaA0KAEoYpXnxRGkIt+GEs=; b=owEBbQKS/ZANAwAIAUCeo8QfGVH7AcsmYgBpRGtSi2cujVCcKzKljcgpoR5IeiU7HBbjRjtMq XGKA5ybsjOJAjMEAAEIAB0WIQTvdRrhHw9z4bnGPFNAnqPEHxlR+wUCaURrUgAKCRBAnqPEHxlR +2dhD/9sE/lhlbTTBuaXXDG9+Smy+AGq0fGM/gavw/WzTBxymsy4LpOjj840bglSa8DuZ83R+Nr Sw2AK5lExPCrEVUYBdIvGKyGMQvZM2wBAa+A06PjQ1x/zTNb+gizXZ/ARs8LVH7FzhRkq2DaUno RSVCiy6mWUkVi2clK7MnbDnCFr7HPByKz4qpFKGylMMXLFnNotgNmimMw2OAxXQfwa0rv68eHt1 TtReXJ0ILDFpRMZjLDG83PmLn7fy2mySKH/ipKNqz7skzk2YPz16NMENQPyeH7uleAua5jfpTUo h0i70bKzt6gR13o6nI/ItT4EaaUBtVwxOrnlMYBcdfcX5fFM+3kwjMlspYVKENQkLCv/klkcV7d ZjlZADz2Vrn5CVHiR+R6VHxkK3WiMhwEqnQM0hvo6XypjvlposQrB3N2QImT+kUS4daTDBcO4nl 6Lba7Ah1lggUTciqX9sgdwJNzQGnlLt6LC78cwiOq+t2aNXNCvy9yqg9FTPewWMieHY8R+/BnE4 dItCBkDteBOo5oWms0WgJR0D2tIl0/OSK110IgDW9WweRL93IzP84A9XGCU8MfM6ATY4zDnM29U 2grvIiD1+m9y8NTR0+odcQaESsR5gYYAIOUXNWCbzXYTbDY97Ac2LcnSVIFhtDCwkW8KJZBYk8k B9bdr90eZvtxdWA== X-Developer-Key: i=da.gomez@samsung.com; a=openpgp; fpr=B2A7A9CFDD03B540FF58B27185F56EA4E9E8138F This series documents the -EEXIST error code reservation in the module loader, building on Lucas's patches [1] that add the runtime safety net. When module_init() returns -EEXIST, kmod interprets this as "module already loaded" and reports success, hiding real init failures. Lucas's patches warn and override this to -EBUSY. These patches document this convention to prevent future cases. This was originally reported in this thread [2]. Link: https://lore.kernel.org/all/20251013-module-warn-ret-v1-0-ab65b41af01f@intel.com/ [1] Link: https://lore.kernel.org/all/aKEVQhJpRdiZSliu@orbyte.nwl.cc/#t [2] Signed-off-by: Daniel Gomez --- Daniel Gomez (2): module: add -EEXIST documentation docs: hacking: clarify reserved -EEXIST in module_init() Documentation/kernel-hacking/hacking.rst | 7 +++++++ kernel/module/main.c | 8 ++++++++ 2 files changed, 15 insertions(+) --- base-commit: e5f0a698b34ed76002dc5cff3804a61c80233a7a change-id: 20251218-dev-module-init-eexists-modules-docs-1dc7cb7a96bb prerequisite-change-id: 20251013-module-warn-ret-59f085298055:v1 prerequisite-patch-id: c3e4f5b5d01c2b48b4c94e51a60469cb74691853 prerequisite-patch-id: 2d5a726a75f3b9d9c256b8478fb6115a92f04354 Best regards, -- Daniel Gomez