+ tools-mm-prevent-page_owner_sort-from-truncating-input.patch added to mm-nonmm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: tools/mm: prevent page_owner_sort from truncating input
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     tools-mm-prevent-page_owner_sort-from-truncating-input.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/tools-mm-prevent-page_owner_sort-from-truncating-input.patch

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

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------------------------------------------------------
From: Warren Xiong <warren.xiong@ugreen.com>
Subject: tools/mm: prevent page_owner_sort from truncating input
Date: Thu, 30 Jul 2026 09:58:09 +0800

page_owner_sort opens the output file with "w" before reading the input. 
If both paths refer to the same file, this truncates the input and the
tool silently processes zero records before returning success.

Delay opening the output file until all input records have been loaded
into memory.  This allows the tool to sort a file in place without
truncating data before it has been consumed.

Link: https://lore.kernel.org/20260730015809.3819606-1-warren.xiong@ugreen.com
Signed-off-by: Warren Xiong <warren.xiong@ugreen.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Vishal Moola <vishal.moola@gmail.com>
Cc: Ye Liu <ye.liu@linux.dev>
Cc: Zhen Ni <zhen.ni@easystack.cn>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/mm/page_owner_sort.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

--- a/tools/mm/page_owner_sort.c~tools-mm-prevent-page_owner_sort-from-truncating-input
+++ a/tools/mm/page_owner_sort.c
@@ -836,8 +836,7 @@ int main(int argc, char **argv)
 	}
 
 	fin = fopen(argv[optind], "r");
-	fout = fopen(argv[optind + 1], "w");
-	if (!fin || !fout) {
+	if (!fin) {
 		usage();
 		perror("open: ");
 		exit(1);
@@ -874,6 +873,13 @@ int main(int argc, char **argv)
 			goto out_free;
 	}
 
+	fout = fopen(argv[optind + 1], "w");
+	if (!fout) {
+		usage();
+		perror("open: ");
+		exit(1);
+	}
+
 	printf("loaded %d\n", list_size);
 
 	printf("sorting ....\n");
_

Patches currently in -mm which might be from warren.xiong@ugreen.com are

tools-mm-prevent-page_owner_sort-from-truncating-input.patch