From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 23089288C2D for ; Mon, 24 Aug 2026 12:02:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787572964; cv=none; b=nVcEgxoB2pQNhd1nDuMk+QIxUAN9/MbtY5rinCAoZdxaTANr2TDv0K+3bZL5yVJoMXMYhJ3bNSZYNw1fjAr3hGue/FLvvfG9n+CIHtivX5z20b0PwE53z4gIJgvc9JEC0JOeuWyo9SEKvvsbxEheaiV07RMmPVhq15pAZdY82bA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787572964; c=relaxed/simple; bh=gZJj56dXZ3m5mpuWg5Y32mLuivOuA0n2jQSSKK4Lf/g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=fEKaplGLj9HHPQy5+MLrFlggiqs1ZGuv2fr/Hw1wIjFTHYmCBciONvSkp2RgrARbvn5n+5zdQ2u8lu3+Vut5x7xBBOXWI0SNfEz405Je0LVRCOg8vN4+WPQvywIx0Np5xv0cCcZwGSudkSW7WAMSOjjPSnND47zY6uJbZuB07zQ= 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=YaUUyk/z; arc=none smtp.client-ip=170.10.129.124 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="YaUUyk/z" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1787572962; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=b4i/vAlF7TVRLwxgQcCoqCNsYOQic8KZ0Txwd6Khtt8=; b=YaUUyk/ztEtGfVKnYUNV27WnzbjEr7J+byS0bZhfS3QqG1Tpg6TMG4lGsVq14dJbTLugRu KXfp1+N7K+0PzDgzyMJgpJHaGsI8zt1+jcOjVMp2sDMeJcArToz7hudSkJAxrhCb+ykns1 J5ESQH96NXlrokuKqZbqYBWXfEGMVBk= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-679-QKIZ5IQHPW2M0-MoD0otjw-1; Mon, 24 Aug 2026 08:02:37 -0400 X-MC-Unique: QKIZ5IQHPW2M0-MoD0otjw-1 X-Mimecast-MFC-AGG-ID: QKIZ5IQHPW2M0-MoD0otjw_1787572956 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-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 2192A19540C5; Mon, 24 Aug 2026 12:02:36 +0000 (UTC) Received: from warthog.com (unknown [10.44.32.15]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 7F8A11800257; Mon, 24 Aug 2026 12:02:32 +0000 (UTC) From: David Howells To: Christian Brauner Cc: David Howells , Paulo Alcantara , netfs@lists.linux.dev, linux-afs@lists.infradead.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Karl Mehltretter , stable@vger.kernel.org Subject: [PATCH 1/3] netfs: Fix uninitialized return value in netfs_unbuffered_write() Date: Mon, 24 Aug 2026 13:02:20 +0100 Message-ID: <20260824120224.504575-2-dhowells@redhat.com> In-Reply-To: <20260824120224.504575-1-dhowells@redhat.com> References: <20260824120224.504575-1-dhowells@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 From: Karl Mehltretter If preparation of the first subrequest fails, netfs_unbuffered_write() exits its loop before ret is initialized. The empty-iterator check can do the same. For synchronous writes, netfs_unbuffered_write_iter_locked() may then return an unrelated error instead of wreq->error. This is reachable through CIFS if cifs_prepare_write() fails to reopen the file or obtain credits. Initialize ret to 0 so the caller returns wreq->error if no data was written, or the number of bytes already written otherwise. Found with Clang's -Wconditional-uninitialized. Fixes: a0b4c7a49137e ("netfs: Fix unbuffered/DIO writes to dispatch subrequests in strict sequence") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter Signed-off-by: David Howells --- fs/netfs/direct_write.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/netfs/direct_write.c b/fs/netfs/direct_write.c index c16fbad286a1..b04019097ab8 100644 --- a/fs/netfs/direct_write.c +++ b/fs/netfs/direct_write.c @@ -95,7 +95,7 @@ static int netfs_unbuffered_write(struct netfs_io_request *wreq) { struct netfs_io_subrequest *subreq = NULL; struct netfs_io_stream *stream = &wreq->io_streams[0]; - int ret; + int ret = 0; _enter("%llx", wreq->len);