From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 C939030CDBC for ; Tue, 23 Jun 2026 16:11:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782231067; cv=none; b=MxRC3zsJuj7C/hwLHKe0stJNeQiS4ODvtoo9KwcPvNarUDBW8SXdQ8ifdXMCJQwb29MWAgycnEhfWUygmoWOV8gqAiFd+954EmT82WubQ9BHupp2jsdoi8AKTe00pWGEQp9yQQCeW4NX6b2WvpPb5LGjApRmmN+x199b8Xl9b7U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782231067; c=relaxed/simple; bh=pritGVRZRMb+ElmOrsmum2PIMY4gU+4D/h7Hti1MNK4=; h=From:In-Reply-To:References:To:Cc:Subject:MIME-Version: Content-Type:Date:Message-ID; b=uxQWWJEbElH9JZcv/W03eizuF/NLj7+uY3a4bG+qdjCm/XhOb6jm1+KKHDriVZzZt4bbJJFx8h9l3OeVzdjIr2AuUumWLnafYi4nsCwgyqxLa/sSeb80LH/QGoqoaWlBWs1B4X4OzUirKG23urPr5mVSdVjTuP0Wg9pVHUHVf2U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=BT9K3lIQ; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="BT9K3lIQ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1782231064; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=wgFx7V3JoLxPvYoJJ8JtntgngDc9RlW7Led92hwOrMM=; b=BT9K3lIQuGRKbHTCpcdRyqzifBCQSyiHK0rR4AcMjnG4Yxzzy2pYQHqs9iPnCa4xxuwhW9 aq67F9oTRF5zOFeEDhad8hilGTPZiFA79fvJCfB5AIeeS//1Pd4r7eg0RhOCr5o1dE2ZLo CCpd3f/jg0NADxESLGHxFGzlrDWG+Z0= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-444-N0dzrl9TOX2ubrDNJNNAEw-1; Tue, 23 Jun 2026 12:11:00 -0400 X-MC-Unique: N0dzrl9TOX2ubrDNJNNAEw-1 X-Mimecast-MFC-AGG-ID: N0dzrl9TOX2ubrDNJNNAEw_1782231058 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id CC6B41802665; Tue, 23 Jun 2026 16:10:57 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.44.48.242]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id D4E80180074B; Tue, 23 Jun 2026 16:10:54 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells In-Reply-To: <33cc8eb4-8831-49b0-80d6-b06544a37920@chenxiaosong.com> References: <33cc8eb4-8831-49b0-80d6-b06544a37920@chenxiaosong.com> To: ChenXiaoSong Cc: dhowells@redhat.com, hongao , Paulo Alcantara , netfs@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot+3c74b1f0c372e98efc32@syzkaller.appspotmail.com Subject: Re: [PATCH] netfs: Fix UAF in netfs_unbuffered_write() on failed preparation 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-ID: <2912806.1782231053.1@warthog.procyon.org.uk> Date: Tue, 23 Jun 2026 17:10:53 +0100 Message-ID: <2912807.1782231053@warthog.procyon.org.uk> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 ChenXiaoSong wrote: > After applying this patch, I can still reproduce the use-after-free issue. Can you get some tracing? I have a suspicion it's a refcount bug. The following tracepoints would be useful: echo 1 > /sys/kernel/tracing/events/netfs/netfs_read/enable echo 1 > /sys/kernel/tracing/events/netfs/netfs_write/enable echo 1 > /sys/kernel/tracing/events/netfs/netfs_rreq/enable echo 1 > /sys/kernel/tracing/events/netfs/netfs_sreq/enable echo 1 > /sys/kernel/tracing/events/netfs/netfs_failure/enable echo 1 > /sys/kernel/tracing/events/error_report/enable And if you can capture this, can you compress the resulting trace and send it to me? Thanks, David