From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 58E973B6C13 for ; Thu, 20 Aug 2026 07:13:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787210025; cv=none; b=Wx37YhmJm0yWmWQJBLzI8lweuH0eM+tk/ZvVqQm9Go89re0DAE7U4ESr9aKybeUmDe0Pam4dUDtBussvMuzKJ0tg//2HMp2m3dWakra/gZ8NlhsfgklUld9rTb4NvYq9U5KjeKmpIGMO3EX86luU7G90EYyvOzyiJCw9UBski8Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787210025; c=relaxed/simple; bh=w89Af4HQM4Wnz2TreiMh5/X3094uvJ9vRZXavIQ5kFM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=W/qsgAEOtWAvGORZwf77n86sTH7oEnuF2LCfApeVoSnESprR/+93EaQ2rNYV+OjiyumW4EgNHuV9dJThw+X0rsgNTcgkVC8EY2fP9iIkoNQmaYP/GfTCpkkIelNtiD7xjthgeeyJIPadP7EVCaXe1xhcQHyYSeu8UdjNg7nSdIU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=C0upUdjV; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="C0upUdjV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4CE441F000E9; Thu, 20 Aug 2026 07:13:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1787210023; bh=VqDtmHKK3lP0uwMYmy3PRQ46Lf0GQ6kisB+dwYXRD3k=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=C0upUdjVPYf7lFETP+YpTavNOPJrj/rF7NS3XV4+494MhW4qj52oFOhsexE7Vzobo 0emrUVBXlA+yN/KKo/q9pcG5mAunURurCRdf2GWNf4vlOzBLu0MU2hcqHZbMdiuIwL RZ0LBPnboiilDkQJ/VOL7vRUqTktyaz/1V9qvhLU= Date: Thu, 20 Aug 2026 09:12:05 +0200 From: Greg KH To: Jaeyoung Chung Cc: abbotti@mev.co.uk, hsweeten@visionengravers.com, linux-kernel@vger.kernel.org, n.zhandarovich@fintech.ru, eulgyukim@snu.ac.kr Subject: Re: [BUG] KASAN: slab-use-after-free Read in comedi_poll Message-ID: <2026082035-devourer-sadly-778e@gregkh> References: <20260819174614.3857878-1-jjy600901@snu.ac.kr> 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=us-ascii Content-Disposition: inline In-Reply-To: <20260819174614.3857878-1-jjy600901@snu.ac.kr> On Thu, Aug 20, 2026 at 02:46:00AM +0900, Jaeyoung Chung wrote: > Hello, > > We found a "KASAN: slab-use-after-free Read in comedi_poll" on Linux v7.2. > The issue was found by our own race fuzzer. We have not analyzed the root cause, > so we do not have a proposed fix to offer. > > To reproduce the race reliably, we applied the delay patch below to the > kernel and ran the C reproducer as root inside an x86_64 QEMU guest. The > crash log we observed, the delay patch and the reproducer are all included > below. > > The reproducer opens /dev/comedi3, which exists if the kernel is booted > with comedi.comedi_num_legacy_minors=4. > > The following kernel config options are required to reproduce the issue: > CONFIG_ISA_BUS=y > CONFIG_COMEDI=y > CONFIG_COMEDI_MISC_DRIVERS=y > CONFIG_COMEDI_ISA_DRIVERS=y > CONFIG_COMEDI_PCL818=y > > We hope this report is useful. Please let us know if any further > information would help. Please just provide a normal patch that can be applied. thanks, greg k-h