On Tue, Aug 11, 2020 at 10:29:29AM -0700, Tom Rix wrote:
>
> On 8/11/20 9:03 AM, Alan Stern wrote:
> > On Tue, Aug 11, 2020 at 08:15:05AM -0700, trix@xxxxxxxxxx wrote:
> >> From: Tom Rix <trix@xxxxxxxxxx>
> >>
> >> clang static analysis reports this representative problem
> >>
> >> realtek_cr.c:639:3: warning: The left expression of the compound
> >> assignment is an uninitialized value. The computed value will
> >> also be garbage
> >> SET_BIT(value, 2);
> >> ^~~~~~~~~~~~~~~~~
> >>
> >> value is set by a successful call to rts51x_read_mem()
> >>
> >> retval = rts51x_read_mem(us, 0xFE77, &value, 1);
> >> if (retval < 0)
> >> return -EIO;
> >>
> >> A successful call to rts51x_read_mem returns 0, failure can
> >> return positive and negative values. This check is wrong
> >> for a number of functions. Fix the retval check.
> >>
> >> Fixes: 065e60964e29 ("ums_realtek: do not use stack memory for DMA")
> >> Signed-off-by: Tom Rix <trix@xxxxxxxxxx>
> >> ---
> >> drivers/usb/storage/realtek_cr.c | 36 ++++++++++++++++----------------
> >> 1 file changed, 18 insertions(+), 18 deletions(-)
> >>
> >> diff --git a/drivers/usb/storage/realtek_cr.c b/drivers/usb/storage/realtek_cr.c
> >> index 3789698d9d3c..b983753e2368 100644
> >> --- a/drivers/usb/storage/realtek_cr.c
> >> +++ b/drivers/usb/storage/realtek_cr.c
> >> @@ -481,16 +481,16 @@ static int enable_oscillator(struct us_data *us)
> >> u8 value;
> >>
> >> retval = rts51x_read_mem(us, 0xFE77, &value, 1);
> >> - if (retval < 0)
> >> + if (retval != STATUS_SUCCESS)
> >> return -EIO;
> > Instead of changing all these call sites, wouldn't it be a lot easier
> > just to change rts51x_read_mem() to make it always return a negative
> > value (such as -EIO) when there's an error?
> >
> > Alan Stern
>
> I thought about that but there was already existing (retval !=
> STATUS_SUCCESS) checks for these calls.
The only values that routine currently returns are
USB_STOR_TRANSPORT_ERROR, -EIO, and 0. None of the callers distinguish
between the first two values, so you can just change the first to the
second.
Note that STATUS_SUCCESS is simply 0.
Alan Stern
