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 63F4527466A; Fri, 2 Jan 2026 12:23:03 +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=1767356587; cv=none; b=ktb1Z5rFBw/2sXAJIIKR36qzRiwq3OsaGwtJiGzEWJqeuk/NucmGeoP6W9wXVR0TOcwZnbMb90Kn8McviqHlQGI/zQuyXsEqvjQKfwhAqeGoFlT+8TW/iddmazq9zhbLVm73iAIorLElFxYpZIZvh3XP7XePnckOuHD3gERAMik= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767356587; c=relaxed/simple; bh=pmqqJuh5Y5fXLBjeFNN71/uuNBNHJNd2F8ECVpYK/pU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Pc+msuQlUv9qw4oYkquCB4nrkS0CceCU5bKy5liugEAz2A7yFB94i8DpXCh+kFzsHFOEcdmuVNWwE/cTnureiozUB72SJj7TpfTQ6CRsWXa8tbppn7ILGjx+eXPvfHSOV8+8lukUwQVATn20/U/L8AYt7m2TSwxv9G4J0zjRSgo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=pZMQqm9/; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="pZMQqm9/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 76E61C116B1; Fri, 2 Jan 2026 12:23:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1767356583; bh=pmqqJuh5Y5fXLBjeFNN71/uuNBNHJNd2F8ECVpYK/pU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pZMQqm9/6EZKu7919ODWJie7df9BcS1vDKtpu2tfmAfBzc351z35swqkErysN8+pt TpwGLs4Xxk86JHVHGPnBiAsrA1/EvoNhAX/TR/burBzUV9UrLW+eUTmresyUfkHFcT EFpGsGJ2PVbhLPhdMMCnwYfN1PK40N8UUZGqt6lc= Date: Fri, 2 Jan 2026 13:23:01 +0100 From: Greg KH To: Holger =?iso-8859-1?Q?Hoffst=E4tte?= Cc: "Dylan E." , stable@vger.kernel.org, linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, sashal@kernel.org, jjohnson@kernel.org Subject: Re: [BUG 6.18.2] Null Pointer Exception in Fair Scheduler Message-ID: <2026010252-pushchair-cornmeal-5c82@gregkh> References: <38b9cad8-1c17-4d89-9f17-44f89fb66ab8@candelatech.com> <39762dfb-d8bd-f1ab-b2f5-a44fa8139911@applied-asynchrony.com> Precedence: bulk X-Mailing-List: linux-wireless@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <39762dfb-d8bd-f1ab-b2f5-a44fa8139911@applied-asynchrony.com> On Wed, Dec 31, 2025 at 09:59:51PM +0100, Holger Hoffstätte wrote: > 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. Will be in the next 6.18.y release, thanks. greg k-h