This is a note to let you know that I've just added the patch titled selftests/resctrl: Fix checking for < 0 for unsigned values to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: selftests-resctrl-fix-checking-for-0-for-unsigned-va.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 8210240c339931139b79e0d130cd18d57b0a4898 Author: Fenghua Yu <fenghua.yu@xxxxxxxxx> Date: Wed Mar 17 02:22:54 2021 +0000 selftests/resctrl: Fix checking for < 0 for unsigned values [ Upstream commit 1205b688c92558a04d8dd4cbc2b213e0fceba5db ] Dan reported following static checker warnings tools/testing/selftests/resctrl/resctrl_val.c:545 measure_vals() warn: 'bw_imc' unsigned <= 0 tools/testing/selftests/resctrl/resctrl_val.c:549 measure_vals() warn: 'bw_resc_end' unsigned <= 0 These warnings are reported because 1. measure_vals() declares 'bw_imc' and 'bw_resc_end' as unsigned long variables 2. Return value of get_mem_bw_imc() and get_mem_bw_resctrl() are assigned to 'bw_imc' and 'bw_resc_end' respectively 3. The returned values are checked for <= 0 to see if the calls failed Checking for < 0 for an unsigned value doesn't make any sense. Fix this issue by changing the implementation of get_mem_bw_imc() and get_mem_bw_resctrl() such that they now accept reference to a variable and set the variable appropriately upon success and return 0, else return < 0 on error. Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Tested-by: Babu Moger <babu.moger@xxxxxxx> Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx> Signed-off-by: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/tools/testing/selftests/resctrl/resctrl_val.c b/tools/testing/selftests/resctrl/resctrl_val.c index 5478c23c62ba..8df557894059 100644 --- a/tools/testing/selftests/resctrl/resctrl_val.c +++ b/tools/testing/selftests/resctrl/resctrl_val.c @@ -300,9 +300,9 @@ static int initialize_mem_bw_imc(void) * Memory B/W utilized by a process on a socket can be calculated using * iMC counters. Perf events are used to read these counters. * - * Return: >= 0 on success. < 0 on failure. + * Return: = 0 on success. < 0 on failure. */ -static float get_mem_bw_imc(int cpu_no, char *bw_report) +static int get_mem_bw_imc(int cpu_no, char *bw_report, float *bw_imc) { float reads, writes, of_mul_read, of_mul_write; int imc, j, ret; @@ -373,13 +373,18 @@ static float get_mem_bw_imc(int cpu_no, char *bw_report) close(imc_counters_config[imc][WRITE].fd); } - if (strcmp(bw_report, "reads") == 0) - return reads; + if (strcmp(bw_report, "reads") == 0) { + *bw_imc = reads; + return 0; + } - if (strcmp(bw_report, "writes") == 0) - return writes; + if (strcmp(bw_report, "writes") == 0) { + *bw_imc = writes; + return 0; + } - return (reads + writes); + *bw_imc = reads + writes; + return 0; } void set_mbm_path(const char *ctrlgrp, const char *mongrp, int resource_id) @@ -438,9 +443,8 @@ static void initialize_mem_bw_resctrl(const char *ctrlgrp, const char *mongrp, * 1. If con_mon grp is given, then read from it * 2. If con_mon grp is not given, then read from root con_mon grp */ -static unsigned long get_mem_bw_resctrl(void) +static int get_mem_bw_resctrl(unsigned long *mbm_total) { - unsigned long mbm_total = 0; FILE *fp; fp = fopen(mbm_total_path, "r"); @@ -449,7 +453,7 @@ static unsigned long get_mem_bw_resctrl(void) return -1; } - if (fscanf(fp, "%lu", &mbm_total) <= 0) { + if (fscanf(fp, "%lu", mbm_total) <= 0) { perror("Could not get mbm local bytes"); fclose(fp); @@ -457,7 +461,7 @@ static unsigned long get_mem_bw_resctrl(void) } fclose(fp); - return mbm_total; + return 0; } pid_t bm_pid, ppid; @@ -549,7 +553,8 @@ static void initialize_llc_occu_resctrl(const char *ctrlgrp, const char *mongrp, static int measure_vals(struct resctrl_val_param *param, unsigned long *bw_resc_start) { - unsigned long bw_imc, bw_resc, bw_resc_end; + unsigned long bw_resc, bw_resc_end; + float bw_imc; int ret; /* @@ -559,13 +564,13 @@ measure_vals(struct resctrl_val_param *param, unsigned long *bw_resc_start) * Compare the two values to validate resctrl value. * It takes 1sec to measure the data. */ - bw_imc = get_mem_bw_imc(param->cpu_no, param->bw_report); - if (bw_imc <= 0) - return bw_imc; + ret = get_mem_bw_imc(param->cpu_no, param->bw_report, &bw_imc); + if (ret < 0) + return ret; - bw_resc_end = get_mem_bw_resctrl(); - if (bw_resc_end <= 0) - return bw_resc_end; + ret = get_mem_bw_resctrl(&bw_resc_end); + if (ret < 0) + return ret; bw_resc = (bw_resc_end - *bw_resc_start) / MB; ret = print_results_bw(param->filename, bm_pid, bw_imc, bw_resc);