Subject: Re: Coverity: cdns_torrent_derived_refclk_is_enabled(): Error handling issues

From: Kees Cook <[email-masked]>
Date: Thu, 1 Apr 2021 13:54:43 -0700

On Wed, Mar 31, 2021 at 02:58:33PM -0700, coverity-bot wrote:
> Hello!
> 
> This is an experimental semi-automated report about issues detected by
> Coverity from a scan of next-20210331 as part of the linux-next scan project:
> https://scan.coverity.com/projects/linux-next-weekly-scan
> 
> You're getting this email because you were associated with the identified
> lines of code (noted below) that were touched by commits:
> 
>   None
>     2cca0228f364 ("phy: cadence-torrent: Add support to drive refclk out")
> 
> Coverity reported the following:
> 
> *** CID 1503589:  Error handling issues  (CHECKED_RETURN)
> /drivers/phy/cadence/phy-cadence-torrent.c: 1678 in cdns_torrent_derived_refclk_is_enabled()
> 1672
> 1673     static int cdns_torrent_derived_refclk_is_enabled(struct clk_hw *hw)
> 1674     {
> 1675     	struct cdns_torrent_derived_refclk *derived_refclk = to_cdns_torrent_derived_refclk(hw);
> 1676     	int val;
> 1677
> vvv     CID 1503589:  Error handling issues  (CHECKED_RETURN)
> vvv     Calling "regmap_field_read" without checking return value (as is done elsewhere 101 out of 117 times).
> 1678     	regmap_field_read(derived_refclk->phy_pipe_cmn_ctrl1_0, &val);
> 1679
> 1680     	return !!val;
> 1681     }
> 1682
> 1683     static const struct clk_ops cdns_torrent_derived_refclk_ops = {

This happens in /drivers/phy/cadence/phy-cadence-sierra.c: 442 in cdns_sierra_pll_mux_get_parent()
too.

-Kees

> 
> If this is a false positive, please let us know so we can mark it as
> such, or teach the Coverity rules to be smarter. If not, please make
> sure fixes get into linux-next. :) For patches fixing this, please
> include these lines (but double-check the "Fixes" first):
> 
> Reported-by: coverity-bot <[email-masked]>
> Addresses-Coverity-ID: 1503589 ("Error handling issues")
> Fixes: 2cca0228f364 ("phy: cadence-torrent: Add support to drive refclk out")
> 
> Thanks for your attention!
> 
> -- 
> Coverity-bot

-- 
Kees Cook