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selftests/mm: read memory information without popen

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read_memory_info() invokes two shell pipelines to obtain MemFree and
Hugepagesize from /proc/meminfo.  It does not check whether popen()
returns NULL before passing the result to fgets(), and it does not call
pclose() when fgets() fails.

Open /proc/meminfo directly and obtain both values in a single pass.  This
removes the unchecked NULL path, closes the file on all paths, and avoids
dependencies on external commands.

The compaction test continues to pass after this change.

Link: https://lore.kernel.org/1785845818-3131-1-git-send-email-warren.xiong@ugreen.com
Signed-off-by: Warren Xiong <warren.xiong@ugreen.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Warren Xiong 2026-08-04 20:16:58 +08:00 committed by Andrew Morton
parent 4e7e499b75
commit 8bc69b8d20
1 changed files with 21 additions and 17 deletions
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38
tools/testing/selftests/mm/compaction_test.c
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@ -29,30 +29,34 @@ struct map_list {
int read_memory_info(unsigned long *memfree, unsigned long *hugepagesize)
{
char buffer[256] = {0};
char *cmd = "cat /proc/meminfo | grep -i memfree | grep -o '[0-9]*'";
FILE *cmdfile = popen(cmd, "r");
char buffer[256];
int found = 0;
FILE *file;
int ret = -1;
if (!(fgets(buffer, sizeof(buffer), cmdfile))) {
ksft_print_msg("Failed to read meminfo: %s\n", strerror(errno));
file = fopen("/proc/meminfo", "r");
if (!file) {
ksft_print_msg("Failed to open /proc/meminfo: %s\n",
strerror(errno));
return -1;
}
pclose(cmdfile);
*memfree = atoll(buffer);
cmd = "cat /proc/meminfo | grep -i hugepagesize | grep -o '[0-9]*'";
cmdfile = popen(cmd, "r");
if (!(fgets(buffer, sizeof(buffer), cmdfile))) {
ksft_print_msg("Failed to read meminfo: %s\n", strerror(errno));
return -1;
while (fgets(buffer, sizeof(buffer), file) && found != 2) {
if (sscanf(buffer, "MemFree: %lu kB", memfree) == 1 ||
sscanf(buffer, "Hugepagesize: %lu kB", hugepagesize) == 1)
found++;
}
pclose(cmdfile);
*hugepagesize = atoll(buffer);
if (ferror(file))
ksft_print_msg("Failed to read /proc/meminfo: %s\n",
strerror(errno));
else if (found != 2)
ksft_print_msg("Failed to parse /proc/meminfo\n");
else
ret = 0;
return 0;
fclose(file);
return ret;
}
int prereq(void)