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 9A3CE46D543 for ; Thu, 27 Aug 2026 13:43:26 +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=1787838209; cv=none; b=SBKMNd1SfbHxfI58KrBQzuOqoEmSNjBsbj+0I7yZ0EZAQZPRu0N15V/6qxgzHIDahqs2hhL0TwRvL47utZAOF6kC5IUT2CiOW/Cvdi6i83R3SGhllUW9JH0Z49HCNV0wFN4Ea2Pof0AFwIrEvi/EKsyb1RDQdVZHK8pRpp/mFwE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787838209; c=relaxed/simple; bh=gZJj56dXZ3m5mpuWg5Y32mLuivOuA0n2jQSSKK4Lf/g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UwuH/MtWF89239I9FP71vAN/kdJVRgkgt8Aq/jmykaKMmIYBSJNeC8Ogc0aPv5vidfwHt/+CXhyEO6/nTURTNEZIMBKwYQ6nolnjXNw+MRMbptsF2Vh8Xy2hPzesaEG5PqVtFoVJ9QzcqwcjnxqNxSlA6UOc20FNfGFWBSHqKfc= 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=Y1fZVGuM; 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="Y1fZVGuM" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1787838204; 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=Y1fZVGuMSGmAT5yjdDdT2K/Agxv8B6cMDUApssRiIjXMY5OMntkOm3cSti0nSKSfgkfD4H CtW2B93Czc1V9vOOEHhGidZ2m2FgXxeMo06flkoX7+HoeeGuw2aG/Jzy0paEdY6R87fLdt DZXGq6TUs8u2AXUlXgcaAPQVJpOHB3I= Received: from mx-prod-mc-06.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-180-6h6MssDMNJ6Amlr5BcUnew-1; Thu, 27 Aug 2026 09:43:18 -0400 X-MC-Unique: 6h6MssDMNJ6Amlr5BcUnew-1 X-Mimecast-MFC-AGG-ID: 6h6MssDMNJ6Amlr5BcUnew_1787838197 Received: from mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.95]) (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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 52F0D1802166; Thu, 27 Aug 2026 13:43:16 +0000 (UTC) Received: from warthog.com (unknown [10.22.88.47]) by mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 36A8E423; Thu, 27 Aug 2026 13:43:13 +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 v4 01/10] netfs: Fix uninitialized return value in netfs_unbuffered_write() Date: Thu, 27 Aug 2026 14:42:54 +0100 Message-ID: <20260827134304.2075713-2-dhowells@redhat.com> In-Reply-To: <20260827134304.2075713-1-dhowells@redhat.com> References: <20260827134304.2075713-1-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 3.6 on 10.30.177.95 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);