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

The patch titled
     Subject: selftests/mm: read memory information without popen
has been added to the -mm mm-new 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-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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

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and is updated there most days

------------------------------------------------------
From: Warren Xiong <[email protected]>
Subject: selftests/mm: read memory information without popen
Date: Mon, 3 Aug 2026 09:30:15 +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]>
Reviewed-by: Andrew Morton <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Liam R. Howlett <[email protected]>
Cc: Lorenzo Stoakes <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Mike Rapoport <[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 |   47 ++++++++++-------
 1 file changed, 29 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
@@ -7,6 +7,7 @@
  * allocated.
  */
 
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/mman.h>
@@ -29,30 +30,40 @@ 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];
+	bool memfree_found = false;
+	bool hugepagesize_found = false;
+	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)) {
+		if (sscanf(buffer, "MemFree: %lu kB", memfree) == 1)
+			memfree_found = true;
+		else if (sscanf(buffer, "Hugepagesize: %lu kB",
+				hugepagesize) == 1)
+			hugepagesize_found = true;
+
+		if (memfree_found && hugepagesize_found) {
+			ret = 0;
+			break;
+		}
 	}
 
-	pclose(cmdfile);
-	*hugepagesize = atoll(buffer);
+	if (ferror(file))
+		ksft_print_msg("Failed to read /proc/meminfo: %s\n",
+			       strerror(errno));
+	else if (ret)
+		ksft_print_msg("Failed to parse /proc/meminfo\n");
 
-	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