From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vincent Bernat , Al Viro Subject: [PATCH 4.1 63/78] 9p: ensure err is initialized to 0 in p9_client_read/write Date: Fri, 11 Sep 2015 15:50:04 -0700 Message-Id: <20150911224615.496411570@linuxfoundation.org> In-Reply-To: <20150911224606.758437370@linuxfoundation.org> References: <20150911224606.758437370@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vincent Bernat commit 999b8b88c6060adf7a9b7907740ae86ace65291e upstream. Some use of those functions were providing unitialized values to those functions. Notably, when reading 0 bytes from an empty file on a 9P filesystem, the return code of read() was not 0. Tested with this simple program: #include #include #include #include #include int main(int argc, const char **argv) { assert(argc == 2); char buffer[256]; int fd = open(argv[1], O_RDONLY|O_NOCTTY); assert(fd >= 0); assert(read(fd, buffer, 0) == 0); return 0; } Signed-off-by: Vincent Bernat Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman --- net/9p/client.c | 2 ++ 1 file changed, 2 insertions(+) --- a/net/9p/client.c +++ b/net/9p/client.c @@ -1541,6 +1541,7 @@ p9_client_read(struct p9_fid *fid, u64 o struct p9_client *clnt = fid->clnt; struct p9_req_t *req; int total = 0; + *err = 0; p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %d\n", fid->fid, (unsigned long long) offset, (int)iov_iter_count(to)); @@ -1616,6 +1617,7 @@ p9_client_write(struct p9_fid *fid, u64 struct p9_client *clnt = fid->clnt; struct p9_req_t *req; int total = 0; + *err = 0; p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n", fid->fid, (unsigned long long) offset,