+ selftests-mm-read-memory-information-without-popen.patch added to mm-unstable branch

The patch titled
     Subject: selftests/mm: read memory information without popen
has been added to the -mm mm-unstable branch.  Its filename is
     selftests-mm-read-memory-information-without-popen.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-mm-read-memory-information-without-popen.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via various
branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there most days

------------------------------------------------------
From: Warren Xiong <[email protected]>
Subject: selftests/mm: read memory information without popen
Date: Tue, 4 Aug 2026 20:16:58 +0800

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/[email protected]
Signed-off-by: Warren Xiong <[email protected]>
Acked-by: David Hildenbrand (Arm) <[email protected]>
Acked-by: Mike Rapoport (Microsoft) <[email protected]>
Cc: Liam R. Howlett <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Suren Baghdasaryan <[email protected]>
Cc: Vlastimil Babka <[email protected]>

Signed-off-by: Andrew Morton <[email protected]>
---

 tools/testing/selftests/mm/compaction_test.c |   40 +++++++++--------
 1 file changed, 22 insertions(+), 18 deletions(-)

--- a/tools/testing/selftests/mm/compaction_test.c~selftests-mm-read-memory-information-without-popen
+++ a/tools/testing/selftests/mm/compaction_test.c
@@ -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");
-
-	if (!(fgets(buffer, sizeof(buffer), cmdfile))) {
-		ksft_print_msg("Failed to read meminfo: %s\n", strerror(errno));
+	char buffer[256];
+	int found = 0;
+	FILE *file;
+	int ret = -1;
+
+	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)
_

Patches currently in -mm which might be from [email protected] are

selftests-mm-read-memory-information-without-popen.patch
tools-mm-prevent-page_owner_sort-from-truncating-input.patch