[kbuild-all] Re: arch/arm/mach-ep93xx/clock.c:154:2: warning: Use of memory after it is freed [clang-analyzer-unix.Malloc]

On Wed, Jan 19, 2022 at 5:46 PM kernel test robot <yujie.liu(a)intel.com&gt; wrote: > > tree: > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > master head: 1d1df41c5a33359a00e919d54eaebfb789711fdc commit: > 9645ccc7bd7a16cd73c3be9dee70cd702b03be37 ep93xx: clock: convert > in-place to COMMON_CLK date: 3 months ago config: > arm-randconfig-c002-20220118 > (https://download.01.org/0day-ci/archive/20220120/202201200359.lTk9zHg4-lk...) > compiler: clang version 14.0.0 > (https://github.com/llvm/llvm-project > 5f782d25a742302d25ef3c8b84b54f7483c2deb9) reproduce (this is a W=1 > build): wget > https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross > -O ~/bin/make.cross chmod +x ~/bin/make.cross # install arm cross > compiling tool for clang build # apt-get install > binutils-arm-linux-gnueabi # > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... > git remote add linus > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > git fetch --no-tags linus master git checkout > 9645ccc7bd7a16cd73c3be9dee70cd702b03be37 # save the config file to > linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang > make.cross ARCH=arm clang-analyzer Hey! This check finally caught something that looks legit! Cool to see 0day bot running clang-analyzer, too! Nikita, can you PTAL?

> > If you fix the issue, kindly add following tag as appropriate > Reported-by: kernel test robot <lkp(a)intel.com&gt; > > > clang-analyzer warnings: (new ones prefixed by >>) > > >> arch/arm/mach-ep93xx/clock.c:154:2: warning: Use of memory > >> after it is freed [clang-analyzer-unix.Malloc] > return &psc->hw; > ^ > arch/arm/mach-ep93xx/clock.c:151:2: note: Taking true branch > if (IS_ERR(clk)) > ^ > arch/arm/mach-ep93xx/clock.c:152:3: note: Memory is released > kfree(psc); > ^~~~~~~~~~ > arch/arm/mach-ep93xx/clock.c:154:2: note: Use of memory after > it is freed return &psc->hw; > ^ ~~~~~~~~ > >> arch/arm/mach-ep93xx/clock.c:484:2: warning: Value stored to > >> 'hw' is never read [clang-analyzer-deadcode.DeadStores] > hw = clk_hw_register_fixed_factor(NULL, "uart", > "xtali", 0, 1, clk_uart_div); ^ > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > >> arch/arm/mach-ep93xx/clock.c:612:2: warning: Value stored to > >> 'hw' is never read [clang-analyzer-deadcode.DeadStores] > hw = clk_hw_register_fixed_factor(NULL, "usb_clk", > "pll2", 0, 1, clk_usb_div); ^ > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > vim +154 arch/arm/mach-ep93xx/clock.c > > ff05c0330b9880 Hartley Sweeten 2009-05-07 125 > 9645ccc7bd7a16 Nikita Shubin 2021-10-18 126 static struct > clk_hw *ep93xx_clk_register_gate(const char *name, 9645ccc7bd7a16 > Nikita Shubin 2021-10-18 127 > const char *parent_name, 9645ccc7bd7a16 Nikita Shubin 2021-10-18 > 128 void __iomem *reg, > 9645ccc7bd7a16 Nikita Shubin 2021-10-18 129 > u8 bit_idx) 9645ccc7bd7a16 Nikita Shubin > 2021-10-18 130 { 9645ccc7bd7a16 Nikita Shubin 2021-10-18 131 > struct clk_init_data init; 9645ccc7bd7a16 Nikita Shubin > 2021-10-18 132 struct clk_psc *psc; 9645ccc7bd7a16 Nikita > Shubin 2021-10-18 133 struct clk *clk; 9645ccc7bd7a16 > Nikita Shubin 2021-10-18 134 9645ccc7bd7a16 Nikita Shubin > 2021-10-18 135 psc = kzalloc(sizeof(*psc), GFP_KERNEL); > 9645ccc7bd7a16 Nikita Shubin 2021-10-18 136 if (!psc) > 9645ccc7bd7a16 Nikita Shubin 2021-10-18 137 > return ERR_PTR(-ENOMEM); 9645ccc7bd7a16 Nikita Shubin 2021-10-18 > 138 9645ccc7bd7a16 Nikita Shubin 2021-10-18 139 > init.name = name; 9645ccc7bd7a16 Nikita Shubin 2021-10-18 140 > init.ops = &clk_ep93xx_gate_ops; 9645ccc7bd7a16 Nikita Shubin > 2021-10-18 141 init.flags = CLK_SET_RATE_PARENT; > 9645ccc7bd7a16 Nikita Shubin 2021-10-18 142 > init.parent_names = (parent_name ? &parent_name : NULL); > 9645ccc7bd7a16 Nikita Shubin 2021-10-18 143 > init.num_parents = (parent_name ? 1 : 0); 9645ccc7bd7a16 Nikita > Shubin 2021-10-18 144 9645ccc7bd7a16 Nikita Shubin 2021-10-18 > 145 psc->reg = reg; 9645ccc7bd7a16 Nikita Shubin > 2021-10-18 146 psc->bit_idx = bit_idx; 9645ccc7bd7a16 > Nikita Shubin 2021-10-18 147 psc->hw.init = &init; > 9645ccc7bd7a16 Nikita Shubin 2021-10-18 148 psc->lock = > &clk_lock; 9645ccc7bd7a16 Nikita Shubin 2021-10-18 149 > 9645ccc7bd7a16 Nikita Shubin 2021-10-18 150 clk = > clk_register(NULL, &psc->hw); 9645ccc7bd7a16 Nikita Shubin > 2021-10-18 151 if (IS_ERR(clk)) 9645ccc7bd7a16 Nikita > Shubin 2021-10-18 152 kfree(psc); probably should `return ERR_CAST(clk);` ? > 9645ccc7bd7a16 Nikita Shubin 2021-10-18 153 > 9645ccc7bd7a16 Nikita Shubin 2021-10-18 @154 return > &psc->hw; ff05c0330b9880 Hartley Sweeten 2009-05-07 155 } > ff05c0330b9880 Hartley Sweeten 2009-05-07 156 > > --- > 0-DAY CI Kernel Test Service, Intel Corporation > https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org >