From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 1694B14F70; Mon, 2 Feb 2026 14:14:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770041651; cv=none; b=aUmXltmFAc6YhC4WdmbLg8Qv4MIqS/ECI96nL0du58B1T0Nzw1IZoGNfKeLXg9WT1nYBMGSprTXBkLoMLD1fx846L3Wq3Fltcjj/RnbLKEAFeHTsCNwiNk/QgkyVXc7ZYGEagKRLYep3tHdSzOtM+5fS72Nhgnb20KPp8EwCE2k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770041651; c=relaxed/simple; bh=JqKUl60vf2mk2q6WHXRfrQSgpfjh0GgY9vftFLodTqw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=W6rFg5ptkSJcFLRUt5qP4ty6rYWgK/ck5rVSva+JNVp/t3yUqK8xafvxSTkGGADJylwb7fPCg8Nn5EsUoaaO3zlRGwz4taXn9q9ByYUXH3PgbLJEevR1GSux08uDNpEjFiHIOHK2ZwUhXbFK2njsa2Qtu27EGxw0IdxYBh3SSw8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=Vuf9nYmW; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="Vuf9nYmW" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=wAc1k4+zJsRHlPOaEXkpUDHcRc6VbrRi9Rvm6Gsx3+s=; b=Vuf9nYmW73DOvW4W1bCFO/Hxhf uedDfAw5PpTFnap8ZcF5G1fMOqOe2VE3qvN/KvhNd6cK/1iX33t9qDefGu5dtybDwg6SHc/mTsaQ3 4pfJ7q7Q7UW/Fqy7tYwfS+di3ywvNLV6d4u27oBErXywciqNsEyG6fUzAxxvO/DPTJKAQQhnfbGdQ 4XAG22Ps8Iq9rSuz7NqYPvMUDTfjmzZ2ZNqT89ksZxR5D2Mda66892y7vk+/5MOUllpHQhIGQ/Zbb I3M46ENR0WVdvoH/48JMvhlIsSh2JE8qpY1GgUH9yrSJOD8h21d48T4MMyRVu5NO597BRMa2BcCMK Xt9iQZtQ==; Received: from willy by casper.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vmugo-0000000Gb0L-1joD; Mon, 02 Feb 2026 14:14:06 +0000 Date: Mon, 2 Feb 2026 14:14:06 +0000 From: Matthew Wilcox To: =?utf-8?B?5p2O6b6Z5YW0?= Cc: syzkaller@googlegroups.com, akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-ext4@vger.kernel.org Subject: Re: [Kernel Bug] KASAN: slab-use-after-free Read in filemap_free_folio Message-ID: References: Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Mon, Feb 02, 2026 at 02:20:50PM +0800, 李龙兴 wrote: > Dear Linux kernel developers and maintainers, > > We would like to report a new kernel bug found by our tool. KASAN: Don't be syzbot. Get your changes into syzkaller upstream and let syzbot do its thing. > Allocated by task 49607: > kasan_save_stack+0x33/0x60 mm/kasan/common.c:56 > kasan_save_track+0x14/0x30 mm/kasan/common.c:77 > unpoison_slab_object mm/kasan/common.c:342 [inline] > __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:368 > kasan_slab_alloc include/linux/kasan.h:252 [inline] > slab_post_alloc_hook mm/slub.c:4978 [inline] > slab_alloc_node mm/slub.c:5288 [inline] > kmem_cache_alloc_lru_noprof+0x254/0x6e0 mm/slub.c:5307 > ext4_alloc_inode+0x28/0x610 fs/ext4/super.c:1393 I'd suggest this is an ext4 problem, not a pagecache problem. syzbot has good heuristics for this kind of thing now. You don't.