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[77.7.4.134]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-499542858b2sm257587555e9.14.2026.08.08.05.35.52 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Sat, 08 Aug 2026 05:35:52 -0700 (PDT) From: Karl Mehltretter To: David Howells Cc: Karl Mehltretter , Paulo Alcantara , netfs@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH] netfs: Fix uninitialized return value in netfs_unbuffered_write() Date: Sat, 8 Aug 2026 14:34:31 +0200 Message-Id: <20260808123431.73554-1-kmehltretter@gmail.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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 subrequ= ests in strict sequence") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-fable-5 Signed-off-by: Karl Mehltretter --- 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 c16fbad286a17..b04019097ab8d 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 =3D NULL; struct netfs_io_stream *stream =3D &wreq->io_streams[0]; - int ret; + int ret =3D 0; =20 _enter("%llx", wreq->len); =20 --=20 2.53.0