From: Tom Rix trix@redhat.com
stable inclusion from linux-4.19.207 commit f4b606f708379d10ea822bde217bdf338a94d096
--------------------------------
commit 161a582bd1d8681095f158d11bc679a58f1d026b upstream.
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.
Make sure to clear the return-value buffer also on allocation failures.
Fixes: 0d130367abf5 ("USB: serial: mos7720: fix control-message error handling") Signed-off-by: Tom Rix trix@redhat.com Link: https://lore.kernel.org/r/20210111220904.1035957-1-trix@redhat.com [ johan: only clear the buffer on errors, amend commit message ] Signed-off-by: Johan Hovold johan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/usb/serial/mos7720.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c index 1e3ee2bfbcd03..d0c8d3800254d 100644 --- a/drivers/usb/serial/mos7720.c +++ b/drivers/usb/serial/mos7720.c @@ -226,8 +226,10 @@ static int read_mos_reg(struct usb_serial *serial, unsigned int serial_portnum, int status;
buf = kmalloc(1, GFP_KERNEL); - if (!buf) + if (!buf) { + *data = 0; return -ENOMEM; + }
status = usb_control_msg(usbdev, pipe, request, requesttype, value, index, buf, 1, MOS_WDR_TIMEOUT);