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 0D83647F3D2 for ; Mon, 5 Oct 2026 14:32:24 +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=1791210752; cv=none; b=Lg9NcykT0BslXIjaLdo2FB13QqN3/IOYLHX2f/LUSWe1nnt0ICZKm/f2P3QoGC9TdN6Q3Jk+eKzycLD0QrtVN6sLOwumsNKYicnhZtWxCmIUQ8OAe+AJxTWyXqG20Mh3yskgw46Ng3LWAmpOK3TI/OtmPC5x3+o4tZOmy5nStgo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791210752; c=relaxed/simple; bh=ZB/E5VH6/lNYsweuS5PqgWCuAFGEg+AlARs8Qe3LMk0=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=pIHWy/bKqaIbN+V3O6t0rxeH4M61o17/yJnLzE3/laW0Ujv/KHYvC59G++5HSRgY7e0xTb9lFxOEzdr9AD3OcApKg6pA7m5+4EnT7q/ukY7nZOsDYkxnpWJeS/aFBq1eukA2Qu1wsR0iwOQmLxLXi0eJNcfJylkL+5TVwGGVjOA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=NogOhaKg; 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="NogOhaKg" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 53AA01F000FF; Mon, 5 Oct 2026 14:32:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1791210742; bh=0+GqJeoCVF22AN3X0lHBxVlRM6ma0jYY5o8ZGBEMQNU=; h=Subject:To:Cc:From:Date; b=NogOhaKg84GJfWLpNbB2bg2Kz6mW3KV6OYWZmn+IgO9ZXZcFC7OzOZrTDFYhA2MsS Bl0kLw1Hs2n1jjLfhn9+RXXobBk/XeVRlc1QwWFr1f/Jo3+xehReIXPu3dQzMOEBeD 6XFGvZAek4sc07plo0DvDy1EdfTVuvIcHdmceRpA= Subject: FAILED: patch "[PATCH] mtd: block2mtd: Fix divide error when erase_size is zero" failed to apply to 6.6-stable tree To: xiaopei01@kylinos.cn,joern@barelysecure.org,miquel.raynal@bootlin.com Cc: From: Date: Mon, 05 Oct 2026 16:32:20 +0200 Message-ID: <2026100520-kilogram-result-00fb@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x b5965c4221165045e19736794ca5f48ae3d67142 # git commit -s git send-email --to '' --in-reply-to '2026100520-kilogram-result-00fb@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From b5965c4221165045e19736794ca5f48ae3d67142 Mon Sep 17 00:00:00 2001 From: Pei Xiao Date: Thu, 13 Aug 2026 10:48:12 +0800 Subject: [PATCH] mtd: block2mtd: Fix divide error when erase_size is zero MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The erase size is parsed from the "block2mtd" module parameter and can be set to zero. add_device() then evaluates if (size % erase_size) with a zero divisor, which triggers a divide error: divide error: 0000 [#1] PREEMPT SMP PTI RIP: 0010:add_device drivers/mtd/devices/block2mtd.c:296 [inline] RIP: 0010:block2mtd_setup2+0x592/0xda0 drivers/mtd/devices/block2mtd.c:459 Call Trace: block2mtd_setup+0x27/0xe0 drivers/mtd/devices/block2mtd.c:476 param_attr_store+0x214/0x310 kernel/params.c:589 module_attr_store+0x65/0x90 kernel/params.c:904 kernfs_fop_write_iter+0x3a4/0x540 fs/kernfs/file.c:345 ... Reject a zero erase size before performing the modulo operation so the existing "erasesize must be a divisor of device size" error path reports the invalid argument and frees the device. Fixes: ea6d833a3fdd ("mtd: block2mtd: check device size") Reported-by: syzbot+b320a4d5f65a61dbbf89@syzkaller.appspotmail.com Closes: https://lore.kernel.org/lkml/6a7b58ba.ac361c09.22ff0a.0045.GAE@google.com/ Suggested-by: Jörn Engel Cc: stable@vger.kernel.org Signed-off-by: Pei Xiao Signed-off-by: Miquel Raynal diff --git a/drivers/mtd/devices/block2mtd.c b/drivers/mtd/devices/block2mtd.c index 03e80b2c4f5a..349fa07be314 100644 --- a/drivers/mtd/devices/block2mtd.c +++ b/drivers/mtd/devices/block2mtd.c @@ -293,7 +293,7 @@ static struct block2mtd_dev *add_device(char *devname, int erase_size, } size = bdev_nr_bytes(bdev); - if ((long)size % erase_size) { + if (!erase_size || (long)size % erase_size) { pr_err("erasesize must be a divisor of device size\n"); goto err_free_block2mtd; }