From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E633CF327AA for ; Tue, 21 Apr 2026 06:03:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Cc:To:In-Reply-To:References :Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=M5voK61wljPEL9MIXMGk8CLB5JWEHYq4E0HHNP/m5yA=; b=Ke/tBS1FBjcO0G4KUH9YOUmmBA Nnq80AQJnl/XU4hXswJzFsIw7QxwrJhnHDD4s3jf2cB5OlRbmmogpR1PHnfoKNfle0tmVsJtHHCxG bd/AixKXHmg3kXUTQXrKzuC2cJKnqPgLP3YWFB15+O4pUJ7U+9LPxkmprASPm2J2eDeIYyRqg2x1d k9hGPeydV4xKUgEsgdtS68tsZ8XgfbYjcKe7OAZG0/4gdbNsURexhleRbHzHua+hmdcZYvm8Vin6h 9NQOCKIB7K0HH8MGs57bireSlWCehMV+TtAjC8P+ylv6G3/WNkHyFrSYIQ+nRzcn2/WzA4y6sXT1o kpeyVa3g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1wF4CW-000000084GN-3Y6x; Tue, 21 Apr 2026 06:03:12 +0000 Received: from jpms-ob02.noc.sony.co.jp ([2001:cf8:ace:41::5]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1wF4CS-000000084Dv-25In for linux-arm-kernel@lists.infradead.org; Tue, 21 Apr 2026 06:03:09 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sony.com; s=s1jp; t=1776751389; x=1808287389; h=from:date:subject:mime-version:content-transfer-encoding: message-id:references:in-reply-to:to:cc; bh=M5voK61wljPEL9MIXMGk8CLB5JWEHYq4E0HHNP/m5yA=; b=MIzS4K4FnHGhIKHSafcEu/PEEjo7OVVk+ceprYK/NJFg2nMU4HY9SOhF p3+m0lU/wqbGiOUDZcJvoIbjeyQdWyxvQQ15A4Mwqd9hlpY6LvUTDZTdX muhL+oZa98OExGOarCz6cXVA8A29H47A5I/gQA8jgTsPccSqa+U57zvSh nwqHbNbo5nlCeaK1pIABoopNfbbO7LaOVNJp8ENT/0Px+oZefKjyrzTdM 22R9fBAfDZbO+hKq2/Pvpgc39v9CObhVQ8Z1bG7WbYmpTlIVmSywI2E/b YZQBI2oTXz9g8RzXmxXlla251yMxv1GUBPpMR+Z1w29vSx2tsfPKTg8oh g==; X-CSE-ConnectionGUID: 2PrZgkTiRKeRYDjjMoU+RA== X-CSE-MsgGUID: snKkoDgmRJ+6IREPdXni1g== Received: from unknown (HELO jpmta-ob02.noc.sony.co.jp) ([IPv6:2001:cf8:0:6e7::7]) by jpms-ob02.noc.sony.co.jp with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Apr 2026 15:03:02 +0900 X-CSE-ConnectionGUID: LTCnBPipSWGuc+TNvzgr2A== X-CSE-MsgGUID: JCCWmIAIRXOq7fv7kUw5XA== X-IronPort-AV: E=Sophos;i="6.23,191,1770562800"; d="scan'208";a="603010295" Received: from unknown (HELO [127.0.1.1]) ([IPv6:2001:cf8:1:573:0:dddd:eb3e:119e]) by jpmta-ob02.noc.sony.co.jp with ESMTP; 21 Apr 2026 15:03:01 +0900 From: Shashank Balaji Date: Tue, 21 Apr 2026 15:02:34 +0900 Subject: [PATCH v2 1/2] kernel: param: handle NULL module_kset in lookup_or_create_module_kobject() MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260421-acpi_mod_name-v2-1-e73f9310dad3@sony.com> References: <20260421-acpi_mod_name-v2-0-e73f9310dad3@sony.com> In-Reply-To: <20260421-acpi_mod_name-v2-0-e73f9310dad3@sony.com> To: Kay Sievers , Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , Suzuki K Poulose , Mike Leach , James Clark , Alexander Shishkin , Maxime Coquelin , Alexandre Torgue , Miguel Ojeda , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Richard Cochran , Jonathan Corbet , Shuah Khan Cc: Shashank Balaji , Rahul Bukte , Daniel Palmer , Tim Bird , linux-kernel@vger.kernel.org, driver-core@lists.linux.dev, coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, rust-for-linux@vger.kernel.org, linux-doc@vger.kernel.org X-Mailer: b4 0.16-dev-3bfbc X-Developer-Signature: v=1; a=openpgp-sha256; l=2030; i=shashank.mahadasyam@sony.com; h=from:subject:message-id; bh=TAodI4xUlrEwxLtFIUjQdPLrsiw6kWJSMaRMWxe/2RQ=; b=owGbwMvMwCU2bX1+URVTXyjjabUkhsznwkKK3M8VPyyJ+fOob7rf792F97YK+ua1sro5tXz3q f29acOdjlIWBjEuBlkxRZZSpepfe1cELek581oRZg4rE8gQBi5OAZhI6wFGhhavhQvMf2ayxh3Z b3TgadmxWv7ixJPb9/4/9DNDa6ccgzrD/4y+FczS57NEdAJDtM/K+orHPZv5seyNw1tjpQufRea F8AEA X-Developer-Key: i=shashank.mahadasyam@sony.com; a=openpgp; fpr=75227BFABDA852A48CCCEB2196AF6F727A028E55 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260420_230308_768657_65BA5432 X-CRM114-Status: GOOD ( 10.21 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org module_kset is initialized in a subsys_initcall. If a built-in driver tries to register before subsys_initcall with its struct device_driver's mod_name set, then a null module_kset is dereferenced via this call trace: [ 0.095865] Call trace: [ 0.095999] _raw_spin_lock+0x4c/0x6c (P) [ 0.096150] kset_find_obj+0x24/0x104 [ 0.096209] lookup_or_create_module_kobject+0x2c/0xd8 [ 0.096274] module_add_driver+0xd4/0x138 [ 0.096328] bus_add_driver+0x16c/0x268 [ 0.096380] driver_register+0x68/0x100 [ 0.096428] __platform_driver_register+0x24/0x30 [ 0.096486] tegra194_cbb_init+0x24/0x30 [ 0.096540] do_one_initcall+0xdc/0x250 [ 0.096608] do_initcall_level+0x9c/0xd0 [ 0.096660] do_initcalls+0x54/0x94 [ 0.096706] do_basic_setup+0x20/0x2c [ 0.096753] kernel_init_freeable+0xc8/0x154 [ 0.096807] kernel_init+0x20/0x1a0 [ 0.096851] ret_from_fork+0x10/0x20 So, return null in lookup_or_create_module_kobject() if module_kset is null. Existing callers handle null already. Fixes: f30c53a873d0 ("MODULES: add the module name for built in kernel drivers") Co-developed-by: Rahul Bukte Signed-off-by: Rahul Bukte Signed-off-by: Shashank Balaji --- This bug is triggered by the next patch on arm64 defconfig: tegra194-cbb tries to register from a pure_initcall, and with the next patch adding mod_name, this null deref is hit. --- kernel/params.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/params.c b/kernel/params.c index 74d620bc2521..881c7328c059 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -752,6 +752,9 @@ lookup_or_create_module_kobject(const char *name) struct kobject *kobj; int err; + if (!module_kset) + return NULL; + kobj = kset_find_obj(module_kset, name); if (kobj) return to_module_kobject(kobj); -- 2.43.0