+ lib-string-fix-memchr_inv-for-large-ranges.patch added to mm-nonmm-unstable branch

+ lib-string-fix-memchr_inv-for-large-ranges.patch added to mm-nonmm-unstable branch

[Andrew Morton]

The patch titled
     Subject: lib/string: fix memchr_inv() for large ranges
has been added to the -mm mm-nonmm-unstable branch.  Its filename is
     lib-string-fix-memchr_inv-for-large-ranges.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/lib-string-fix-memchr_inv-for-large-ranges.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: Bradley Morgan <include@grrlz.net>
Subject: lib/string: fix memchr_inv() for large ranges
Date: Sun, 21 Jun 2026 12:11:33 +0000

memchr_inv() takes a size_t length but counts 8 byte words in an unsigned
int.  At 32GiB that count wraps, so the scan can quietly miss most of the
range.

Use size_t for the word count.

Link: https://lore.kernel.org/20260621121133.16460-1-include@grrlz.net
Fixes: 798248206b59 ("lib/string.c: introduce memchr_inv()")
Signed-off-by: Bradley Morgan <include@grrlz.net>
Cc: Akinbou Mita <akinobu.mita@gmail.com>
Cc: Andy Shevchenko <andy@kernel.org>
Cc: Christoph Lameer <cl@linux-foundation.org>
Cc: Joern Engel <joern@logfs.org>
Cc: Kees Cook <kees@kernel.org>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/string.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/lib/string.c~lib-string-fix-memchr_inv-for-large-ranges
+++ a/lib/string.c
@@ -821,7 +821,8 @@ void *memchr_inv(const void *start, int
 {
 	u8 value = c;
 	u64 value64;
-	unsigned int words, prefix;
+	size_t words;
+	unsigned int prefix;
 
 	if (bytes <= 16)
 		return check_bytes8(start, value, bytes);
_

Patches currently in -mm which might be from include@grrlz.net are

lib-string-fix-memchr_inv-for-large-ranges.patch