Re: [PATCH v2 2/3] phy: rockchip-pcie: Use devm_clk_get_enabled() helper

[Dan Carpenter]

Hi Anand,

kernel test robot noticed the following build warnings:

url:    https://github.com/intel-lab-lkp/linux/commits/Anand-Moon/phy-rockchip-pcie-Simplify-error-handling-with-dev_err_probe/20241007-115910
base:   8f602276d3902642fdc3429b548d73c745446601
patch link:    https://lore.kernel.org/r/20241007035616.2701-3-linux.amoon%40gmail.com
patch subject: [PATCH v2 2/3] phy: rockchip-pcie: Use devm_clk_get_enabled() helper
config: loongarch-randconfig-r071-20241009 (https://download.01.org/0day-ci/archive/20241009/202410092019.vGogfPIO-lkp@xxxxxxxxx/config)
compiler: loongarch64-linux-gcc (GCC) 14.1.0

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
| Closes: https://lore.kernel.org/r/202410092019.vGogfPIO-lkp@xxxxxxxxx/

smatch warnings:
drivers/phy/rockchip/phy-rockchip-pcie.c:278 rockchip_pcie_phy_init() warn: missing error code 'err'

vim +/err +278 drivers/phy/rockchip/phy-rockchip-pcie.c

fcffee3d54fcad drivers/phy/phy-rockchip-pcie.c          Shawn Lin  2016-09-01  269  static int rockchip_pcie_phy_init(struct phy *phy)
fcffee3d54fcad drivers/phy/phy-rockchip-pcie.c          Shawn Lin  2016-09-01  270  {
90a7612d070d5c drivers/phy/rockchip/phy-rockchip-pcie.c Shawn Lin  2017-07-19  271  	struct phy_pcie_instance *inst = phy_get_drvdata(phy);
90a7612d070d5c drivers/phy/rockchip/phy-rockchip-pcie.c Shawn Lin  2017-07-19  272  	struct rockchip_pcie_phy *rk_phy = to_pcie_phy(inst);
fcffee3d54fcad drivers/phy/phy-rockchip-pcie.c          Shawn Lin  2016-09-01  273  	int err = 0;
fcffee3d54fcad drivers/phy/phy-rockchip-pcie.c          Shawn Lin  2016-09-01  274  
90a7612d070d5c drivers/phy/rockchip/phy-rockchip-pcie.c Shawn Lin  2017-07-19  275  	mutex_lock(&rk_phy->pcie_mutex);
90a7612d070d5c drivers/phy/rockchip/phy-rockchip-pcie.c Shawn Lin  2017-07-19  276  
90a7612d070d5c drivers/phy/rockchip/phy-rockchip-pcie.c Shawn Lin  2017-07-19  277  	if (rk_phy->init_cnt++)
90a7612d070d5c drivers/phy/rockchip/phy-rockchip-pcie.c Shawn Lin  2017-07-19 @278  		goto err_out;

Originally, this path just unlocked at returned zero.

90a7612d070d5c drivers/phy/rockchip/phy-rockchip-pcie.c Shawn Lin  2017-07-19  279  
fcffee3d54fcad drivers/phy/phy-rockchip-pcie.c          Shawn Lin  2016-09-01  280  	err = reset_control_assert(rk_phy->phy_rst);
fcffee3d54fcad drivers/phy/phy-rockchip-pcie.c          Shawn Lin  2016-09-01  281  	if (err) {
fcffee3d54fcad drivers/phy/phy-rockchip-pcie.c          Shawn Lin  2016-09-01  282  		dev_err(&phy->dev, "assert phy_rst err %d\n", err);
3114329651e74f drivers/phy/rockchip/phy-rockchip-pcie.c Anand Moon 2024-10-07  283  		goto err_out;
fcffee3d54fcad drivers/phy/phy-rockchip-pcie.c          Shawn Lin  2016-09-01  284  	}
fcffee3d54fcad drivers/phy/phy-rockchip-pcie.c          Shawn Lin  2016-09-01  285  
90a7612d070d5c drivers/phy/rockchip/phy-rockchip-pcie.c Shawn Lin  2017-07-19  286  	mutex_unlock(&rk_phy->pcie_mutex);
90a7612d070d5c drivers/phy/rockchip/phy-rockchip-pcie.c Shawn Lin  2017-07-19  287  	return 0;
fcffee3d54fcad drivers/phy/phy-rockchip-pcie.c          Shawn Lin  2016-09-01  288  
3114329651e74f drivers/phy/rockchip/phy-rockchip-pcie.c Anand Moon 2024-10-07  289  err_out:
90a7612d070d5c drivers/phy/rockchip/phy-rockchip-pcie.c Shawn Lin  2017-07-19  290  	rk_phy->init_cnt--;

Now it decrements the counter so presumably it leads to an underflow/use after
free.

90a7612d070d5c drivers/phy/rockchip/phy-rockchip-pcie.c Shawn Lin  2017-07-19  291  	mutex_unlock(&rk_phy->pcie_mutex);
fcffee3d54fcad drivers/phy/phy-rockchip-pcie.c          Shawn Lin  2016-09-01  292  	return err;
fcffee3d54fcad drivers/phy/phy-rockchip-pcie.c          Shawn Lin  2016-09-01  293  }

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