From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.itouring.de (mail.itouring.de [85.10.202.141]) (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 E428A1C7012; Wed, 31 Dec 2025 20:59:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=85.10.202.141 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767214804; cv=none; b=m3kX6/KQSXSrY2klIeJYsp4Ur1C2NmhjvIXn1RmfnmWMmusqFMhfGpGRPoEWg/OUrzQ8NkqTnDQiAcKzOi3gYu/EMgWwoCMSw29R5aGDWjm3tqpTF99dy4VqfzFVnNW6MJdAWb3UWLYotX5EBIjYWGXTxSb3mE0968h1w6sO0w4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767214804; c=relaxed/simple; bh=05il5/H64ucfD4ZVvaPxo+1OEQH5VOUt/8ASoK+VH5c=; h=Subject:To:Cc:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=QT6SxLX4cr3pv8m27I1C9F7H8xFX756tgjS3QSLT9gjSdEXgRVGiSLQGnJnVACOSYv1lfL1YEndZlvK7Mdm8+DHn7LpCHFIKRze6DFOVj6PIlmds+7eM6r1BoaoSQKFrQlv9gecY0QR8/6HapGqmZKlAkj3t+x3xxpTC5C/oS+s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=applied-asynchrony.com; spf=pass smtp.mailfrom=applied-asynchrony.com; arc=none smtp.client-ip=85.10.202.141 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=applied-asynchrony.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=applied-asynchrony.com Received: from tux.applied-asynchrony.com (p5b07ecd7.dip0.t-ipconnect.de [91.7.236.215]) by mail.itouring.de (Postfix) with ESMTPSA id 2407FD20158; Wed, 31 Dec 2025 21:59:52 +0100 (CET) Received: from [192.168.100.221] (hho.applied-asynchrony.com [192.168.100.221]) by tux.applied-asynchrony.com (Postfix) with ESMTP id B7C366016E288; Wed, 31 Dec 2025 21:59:51 +0100 (CET) Subject: Re: [BUG 6.18.2] Null Pointer Exception in Fair Scheduler To: "Dylan E." , stable@vger.kernel.org, linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org Cc: gregkh@linuxfoundation.org, sashal@kernel.org, jjohnson@kernel.org References: <38b9cad8-1c17-4d89-9f17-44f89fb66ab8@candelatech.com> From: =?UTF-8?Q?Holger_Hoffst=c3=a4tte?= Organization: Applied Asynchrony, Inc. Message-ID: <39762dfb-d8bd-f1ab-b2f5-a44fa8139911@applied-asynchrony.com> Date: Wed, 31 Dec 2025 21:59:51 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <38b9cad8-1c17-4d89-9f17-44f89fb66ab8@candelatech.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit On 2025-12-31 21:00, Dylan E. wrote: > Hello, > > When booting into the v6.18.2 tagged kernel from linux-stable, I get the following > stack trace while booting into the system every 1 in 5 boots or so, usually during > fsck or early systemd service initialization: > > --- > BUG: kernel NULL pointer dereference, address: 0000000000000051 > #PF: supervisor read access in kernel mode > #PF: error_code(0x0000) - not-present page > PGD 0 P4D 0 > Oops: Oops: 0000 [#1] SMP > CPU: 0 UID: 0 PID: 15 Comm: rcu_preempt Not tainted 6.18.2 #2 PREEMPT(full) > Hardware name:  /SKYBAY, BIOS 5.12 06/27/2017 > RIP: 0010:pick_task_fair+0x57/0x160 > Code: 66 90 66 90 48 8b 5d 50 48 85 db 74 10 48 8b 73 70 48 89 ef e8 3a 74 ff ff 85 c0 75 71 be 01 00 00 00 48 89 ef e8 29 a5 ff ff <80> 78 51 00 48 89 c3 0f 85 80 00 00 00 48 85 c0 0f 84 87 00 00 00 > RSP: 0000:ffffc900000d3cf8 EFLAGS: 00010086 > RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000800 > RDX: fffffc02295d3c00 RSI: 0000000000000800 RDI: 0000000002edc4f2 > RBP: ffff888108f13000 R08: 0000000000000400 R09: 0000000000000002 > R10: 0000000000000260 R11: ffff888108b74200 R12: ffff888265c2cd00 > R13: 0000000000000000 R14: ffff888265c2cd80 R15: ffffffff827c6fa0 > FS:  0000000000000000(0000) GS:ffff8882e2724000(0000) knlGS:0000000000000000 > CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000051 CR3: 00000001110a5003 CR4: 00000000003706f0 > Call Trace: >   >  pick_next_task_fair+0x1d/0x3d0 >  __schedule+0x1ee/0x10c0 Welcome to the club :) I already reported it and requested a fix in: https://lore.kernel.org/stable/04b82346-c38a-08e2-49d5-d64981eb7dae@applied-asynchrony.com/ You can apply the patch from: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=127b90315ca07ccad2618db7ba950a63e3b32d22 which should fix it. cheers Holger