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[75.142.250.213]) by smtp.gmail.com with ESMTPSA id m15sm692170ilh.6.2021.01.11.14.09.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Jan 2021 14:09:10 -0800 (PST) From: trix@redhat.com To: johan@kernel.org, gregkh@linuxfoundation.org, natechancellor@gmail.com, ndesaulniers@google.com Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com, Tom Rix Subject: [PATCH] USB: serial: mos7720: improve handling of a kmalloc failure in read_mos_reg() Date: Mon, 11 Jan 2021 14:09:04 -0800 Message-Id: <20210111220904.1035957-1-trix@redhat.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tom Rix clang static analysis reports this problem mos7720.c:352:2: warning: Undefined or garbage value returned to caller return d; ^~~~~~~~ In the parport_mos7715_read_data()'s call to read_mos_reg(), 'd' is only set after the alloc block. buf = kmalloc(1, GFP_KERNEL); if (!buf) return -ENOMEM; Although the problem is reported in parport_most7715_read_data(), none of the callee's of read_mos_reg() check the return status. So move the clearing of data to before the malloc. Fixes: 0d130367abf5 ("USB: serial: mos7720: fix control-message error handling") Signed-off-by: Tom Rix --- drivers/usb/serial/mos7720.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c index 41ee2984a0df..23e8162c768b 100644 --- a/drivers/usb/serial/mos7720.c +++ b/drivers/usb/serial/mos7720.c @@ -214,6 +214,7 @@ static int read_mos_reg(struct usb_serial *serial, unsigned int serial_portnum, u8 *buf; int status; + *data = 0; buf = kmalloc(1, GFP_KERNEL); if (!buf) return -ENOMEM; @@ -227,7 +228,6 @@ static int read_mos_reg(struct usb_serial *serial, unsigned int serial_portnum, "mos7720: usb_control_msg() failed: %d\n", status); if (status >= 0) status = -EIO; - *data = 0; } kfree(buf); -- 2.27.0