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selftests/resctrl: Fix schemata write error check

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Writing bitmasks to the schemata can fail when the bitmask doesn't
adhere to constraints defined by what a particular CPU supports.
Some example of constraints are max length or having contiguous bits.
The driver should properly return errors when any rule concerning
bitmask format is broken.

Resctrl FS returns error codes from fprintf() only when fclose() is
called. Current error checking scheme allows invalid bitmasks to be
written into schemata file and the selftest doesn't notice because the
fclose() error code isn't checked.

Substitute fopen(), flose() and fprintf() with open(), close() and
write() to avoid error code buffering between fprintf() and fclose().

Remove newline character from the schema string after writing it to
the schemata file so it prints correctly before function return.

Pass the string generated with strerror() to the "reason" buffer so
the error message is more verbose. Extend "reason" buffer so it can hold
longer messages.

Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
This commit is contained in:
Maciej Wieczor-Retman 2023-10-10 09:56:11 +02:00 committed by Shuah Khan
parent ef43c30858
commit 20d96b25cc
1 changed files with 26 additions and 15 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

41
tools/testing/selftests/resctrl/resctrlfs.c
View file

@ -8,6 +8,7 @@
* Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>,
* Fenghua Yu <fenghua.yu@intel.com>
*/
#include <fcntl.h>
#include <limits.h>
#include "resctrl.h"
@ -490,9 +491,8 @@ int write_bm_pid_to_resctrl(pid_t bm_pid, char *ctrlgrp, char *mongrp,
*/
int write_schemata(char *ctrlgrp, char *schemata, int cpu_no, char *resctrl_val)
{
char controlgroup[1024], schema[1024], reason[64];
int resource_id, ret = 0;
FILE *fp;
char controlgroup[1024], reason[128], schema[1024] = {};
int resource_id, fd, schema_len = -1, ret = 0;
if (strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR)) &&
strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR)) &&
@ -520,28 +520,39 @@ int write_schemata(char *ctrlgrp, char *schemata, int cpu_no, char *resctrl_val)
if (!strncmp(resctrl_val, CAT_STR, sizeof(CAT_STR)) ||
!strncmp(resctrl_val, CMT_STR, sizeof(CMT_STR)))
sprintf(schema, "%s%d%c%s", "L3:", resource_id, '=', schemata);
schema_len = snprintf(schema, sizeof(schema), "%s%d%c%s\n",
"L3:", resource_id, '=', schemata);
if (!strncmp(resctrl_val, MBA_STR, sizeof(MBA_STR)) ||
!strncmp(resctrl_val, MBM_STR, sizeof(MBM_STR)))
sprintf(schema, "%s%d%c%s", "MB:", resource_id, '=', schemata);
fp = fopen(controlgroup, "w");
if (!fp) {
sprintf(reason, "Failed to open control group");
schema_len = snprintf(schema, sizeof(schema), "%s%d%c%s\n",
"MB:", resource_id, '=', schemata);
if (schema_len < 0 || schema_len >= sizeof(schema)) {
snprintf(reason, sizeof(reason),
"snprintf() failed with return value : %d", schema_len);
ret = -1;
goto out;
}
if (fprintf(fp, "%s\n", schema) < 0) {
sprintf(reason, "Failed to write schemata in control group");
fclose(fp);
fd = open(controlgroup, O_WRONLY);
if (fd < 0) {
snprintf(reason, sizeof(reason),
"open() failed : %s", strerror(errno));
ret = -1;
goto out;
goto err_schema_not_empty;
}
fclose(fp);
if (write(fd, schema, schema_len) < 0) {
snprintf(reason, sizeof(reason),
"write() failed : %s", strerror(errno));
close(fd);
ret = -1;
goto err_schema_not_empty;
}
close(fd);
err_schema_not_empty:
schema[schema_len - 1] = 0;
out:
ksft_print_msg("Write schema \"%s\" to resctrl FS%s%s\n",
schema, ret ? " # " : "",