[PATCH v2 09/16] perf: stm32: introduce DDRPERFM driver

[Dan Carpenter]

Hi Clément,

kernel test robot noticed the following build warnings:

url:    https://github.com/intel-lab-lkp/linux/commits/Cl-ment-Le-Goffic/bus-firewall-move-stm32_firewall-header-file-in-include-folder/20250712-030518
base:   d7b8f8e20813f0179d8ef519541a3527e7661d3a
patch link:    https://lore.kernel.org/r/20250711-ddrperfm-upstream-v2-9-cdece720348f%40foss.st.com
patch subject: [PATCH v2 09/16] perf: stm32: introduce DDRPERFM driver
config: sh-randconfig-r071-20250712 (https://download.01.org/0day-ci/archive/20250712/202507122125.eve8lg60-lkp@intel.com/config)
compiler: sh4-linux-gcc (GCC) 13.4.0

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 at intel.com>
| Reported-by: Dan Carpenter <dan.carpenter at linaro.org>
| Closes: https://lore.kernel.org/r/202507122125.eve8lg60-lkp@intel.com/

smatch warnings:
drivers/perf/stm32_ddr_pmu.c:380 stm32_ddr_pmu_get_counter() warn: variable dereferenced before check 'pmu' (see line 376)
drivers/perf/stm32_ddr_pmu.c:380 stm32_ddr_pmu_get_counter() warn: variable dereferenced before check 'event' (see line 377)

vim +/pmu +380 drivers/perf/stm32_ddr_pmu.c

73af3c4ba702d7 Clément Le Goffic 2025-07-11  374  static int stm32_ddr_pmu_get_counter(struct stm32_ddr_pmu *pmu, struct perf_event *event)
73af3c4ba702d7 Clément Le Goffic 2025-07-11  375  {
73af3c4ba702d7 Clément Le Goffic 2025-07-11 @376  	u32 time_cnt_idx = pmu->cfg->time_cnt_idx;
                                                                           ^^^^^^^^

73af3c4ba702d7 Clément Le Goffic 2025-07-11 @377  	u32 config = event->attr.config;
                                                                     ^^^^^^^

73af3c4ba702d7 Clément Le Goffic 2025-07-11  378  	struct stm32_ddr_cnt *cnt;
73af3c4ba702d7 Clément Le Goffic 2025-07-11  379  
73af3c4ba702d7 Clément Le Goffic 2025-07-11 @380  	if (!pmu || !event)
                                                            ^^^^^^^^^^^^^^
Checks are too late.  The variables have already been dereferenced.

73af3c4ba702d7 Clément Le Goffic 2025-07-11  381  		return -EINVAL;
73af3c4ba702d7 Clément Le Goffic 2025-07-11  382  
73af3c4ba702d7 Clément Le Goffic 2025-07-11  383  	pmu->selected_set = GROUP_VALUE(config);
73af3c4ba702d7 Clément Le Goffic 2025-07-11  384  
73af3c4ba702d7 Clément Le Goffic 2025-07-11  385  	if (config == TIME_CNT) {

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